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Sarfraz M, Aziz M, Afzal S, Channar PA, Alsfouk BA, Kandhro GA, Hassan S, Sultan A, Hamad A, Arafat M, Qaiser MN, Ahmed A, Siddique F, Ejaz SA. Repurposing of Strychnine as the Potential Inhibitors of Aldo-keto Reductase Family 1 Members B1 and B10: Computational Modeling and Pharmacokinetic Analysis. Protein J 2024; 43:207-224. [PMID: 37940790 DOI: 10.1007/s10930-023-10163-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/03/2023] [Indexed: 11/10/2023]
Abstract
AKR1B1 and AKR1B10 are important members of aldo-keto reductase family which plays a significant role in cancer progression by modulating cellular metabolism. These enzymes are involved in various metabolic processes, including the synthesis and metabolism of hormones, detoxification of reactive aldehydes, and the reduction of various endogenous and exogenous compounds. This study aimed to explore the potential of strychnine as an anticancer agent by targeting AKR1B1 and AKR1B10 via drug repurposing approach. To assess the drug-like properties of strychnine, a physiologically based pharmacokinetic (PKPB) model and High Throughput Pharmacokinetics (HTPK) approach were employed. The obtained results fell within the expected range for drug molecules, confirming its suitability for further investigation. Additionally, density functional theory (DFT) studies were conducted to gain insight into the electronic properties contributing to the drug molecule's reactivity. Building upon the promising DFT results, molecular docking analysis using the AutoDock tool was performed to examine the binding interactions between strychnine and the proposed targets, AKR1B1 and AKR1B10. Findings from the molecular docking studies suggested a higher probability of strychnine acting as an inhibitor of AKR1B1 and AKR1B10 with docking scores of - 30.84 and - 29.36 kJ/mol respectively. To validate the stability of the protein-ligand complex, Molecular Dynamic Simulation (MDS) studies were conducted, revealing the formation of a stable complex between the enzymes and strychnine. This comprehensive approach sheds light on the potential effectiveness of strychnine as a treatment for breast, lung, liver, and pancreatic cancers, as well as related malignancies. The novel insights gained from the physiologically based pharmacokinetic modeling, density functional theory, molecular docking, and molecular dynamics simulations collectively support the prospect of strychnine as a promising molecule for anticancer therapy. Further investigations are warranted to validate these findings and explore the therapeutic potential of strychnine in preclinical and clinical settings.
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Affiliation(s)
- Muhammad Sarfraz
- College of Pharmacy, Al Ain University, Al Ain Campus, 64141, Al Ain, United Arab Emirates
| | - Mubashir Aziz
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, The Islamia University of Bahawalpur, Bahawalpur, 63100, Pakistan
| | - Saira Afzal
- Faculty of Pharmacy, The University of Lahore, Lahore, Pakistan
| | - Pervaiz Ali Channar
- Department of Basic Sciences, Mathematics and Humanities, Dawood University of Engineering and Technology, Karachi, 74800, Pakistan
| | - Bshra A Alsfouk
- Department of Pharmaceutical Sciences, College of Pharmacy, Princess Nourah bint Abdulrahman University, P.O Box 84428, 11671, Riyadh, Saudi Arabia
| | - Ghulam Abbas Kandhro
- Department of Basic Sciences, Mathematics and Humanities, Dawood University of Engineering and Technology, Karachi, 74800, Pakistan
| | - Sidra Hassan
- Bahawalpur College of Pharmacy, Bahawalpur Medical and Dental College, Bahawalpur, Pakistan
| | - Ahlam Sultan
- Department of Pharmaceutical Sciences, College of Pharmacy, Princess Nourah bint Abdulrahman University, P.O Box 84428, 11671, Riyadh, Saudi Arabia
| | - Asad Hamad
- Faculty of Pharmacy, Grand Asian University, Sialkot, 51310, Punjab, Pakistan
| | - Mosab Arafat
- College of Pharmacy, Al Ain University, Al Ain Campus, 64141, Al Ain, United Arab Emirates
| | | | - Aftab Ahmed
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, The Islamia University of Bahawalpur, Bahawalpur, 63100, Pakistan
| | - Farhan Siddique
- Department of Chemistry and Biochemistry, Texas Tech Universit, Lubboc, TX, 79409-1061, USA
- Department of Pharmaceutical Chemistry, Faculty of Pharmac, Bahauddian Zakariya University, Multan, 60800, Pakistan
| | - Syeda Abida Ejaz
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, The Islamia University of Bahawalpur, Bahawalpur, 63100, Pakistan.
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Hong B, Grzech D, Caputi L, Sonawane P, López CER, Kamileen MO, Hernández Lozada NJ, Grabe V, O'Connor SE. Biosynthesis of strychnine. Nature 2022; 607:617-622. [PMID: 35794473 PMCID: PMC9300463 DOI: 10.1038/s41586-022-04950-4] [Citation(s) in RCA: 33] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Accepted: 06/08/2022] [Indexed: 11/08/2022]
Abstract
Strychnine is a natural product that, through isolation, structural elucidation and synthetic efforts, shaped the field of organic chemistry. Currently, strychnine is used as a pesticide to control rodents1 because of its potent neurotoxicity2,3. The polycyclic architecture of strychnine has inspired chemists to develop new synthetic transformations and strategies to access this molecular scaffold4, yet it is still unknown how plants create this complex structure. Here we report the biosynthetic pathway of strychnine, along with the related molecules brucine and diaboline. Moreover, we successfully recapitulate strychnine, brucine and diaboline biosynthesis in Nicotiana benthamiana from an upstream intermediate, thus demonstrating that this complex, pharmacologically active class of compounds can now be harnessed through metabolic engineering approaches.
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Affiliation(s)
- Benke Hong
- Department of Natural Product Biosynthesis, Max-Planck Institute for Chemical Ecology, Jena, Germany
| | - Dagny Grzech
- Department of Natural Product Biosynthesis, Max-Planck Institute for Chemical Ecology, Jena, Germany
| | - Lorenzo Caputi
- Department of Natural Product Biosynthesis, Max-Planck Institute for Chemical Ecology, Jena, Germany
| | - Prashant Sonawane
- Department of Natural Product Biosynthesis, Max-Planck Institute for Chemical Ecology, Jena, Germany
| | - Carlos E Rodríguez López
- Department of Natural Product Biosynthesis, Max-Planck Institute for Chemical Ecology, Jena, Germany
| | - Mohamed Omar Kamileen
- Department of Natural Product Biosynthesis, Max-Planck Institute for Chemical Ecology, Jena, Germany
| | - Néstor J Hernández Lozada
- Department of Natural Product Biosynthesis, Max-Planck Institute for Chemical Ecology, Jena, Germany
| | - Veit Grabe
- Microscopic Imaging Service Group, Max-Planck Institute for Chemical Ecology, Jena, Germany
| | - Sarah E O'Connor
- Department of Natural Product Biosynthesis, Max-Planck Institute for Chemical Ecology, Jena, Germany.
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Ismail TA, Shehata TM, Mohamed DI, Elsewedy HS, Soliman WE. Quality by Design for Development, Optimization and Characterization of Brucine Ethosomal Gel for Skin Cancer Delivery. Molecules 2021; 26:molecules26113454. [PMID: 34200144 PMCID: PMC8201187 DOI: 10.3390/molecules26113454] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2021] [Revised: 05/24/2021] [Accepted: 06/05/2021] [Indexed: 11/16/2022] Open
Abstract
Natural products have been extensively used for treating a wide variety of disorders. In recent times, Brucine (BRU) as one of the natural medications extracted from seeds of nux vomica, was investigated for its anticancer activity. As far as we know, this is the first study on BRU anticancer activity against skin cancer. Thus, the rational of this work was implemented to develop, optimize and characterize the anticancer activity of BRU loaded ethosomal gel. Basically, thin film hydration method was used to formulate BRU ethosomal preparations, by means of Central composite design (CCD), which were operated to construct (32) factorial design. Two independent variables were designated (phospholipid percentage and ethanol percentage) with three responses (vesicular size, encapsulation efficiency and flux). Based on the desirability function, one formula was selected and incorporated into HPMC gel base to develop BRU loaded ethosomal gel. The fabricated gel was assessed for all physical characterization. In-vitro release investigation, ex-vivo permeation and MTT calorimetric assay were performed. BRU loaded ethosomal gel exhibited acceptable values for the characterization parameters which stand proper for topical application. In-vitro release investigation was efficiently prolonged for 6 h. The flux from BRU loaded ethosome was enhanced screening optimum SSTF value. Finally, in-vitro cytotoxicity study proved that BRU loaded ethosomal gel significantly improved the anticancer activity of the drug against A375 human melanoma cell lines. Substantially, the investigation proposed a strong motivation for further study of the lately developed BRU loaded ethosomal gel as a prospective therapeutic strategy for melanoma treatment.
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Affiliation(s)
- Tamer A. Ismail
- Department of Clinical Laboratory Sciences, Turabah University College, Taif University, P.O. Box 11099, Taif 21944, Saudi Arabia;
| | - Tamer M. Shehata
- Department of Pharmaceutical Sciences, College of Clinical Pharmacy, King Faisal University, Al-Hofuf 36362, Saudi Arabia;
- Correspondence: ; Tel.: +966-56-478-7190
| | - Dalia I. Mohamed
- Department of Biochemistry, Zagazig Branch, Agriculture Research Center, Animal Health Research Institute, Zagazig 44519, Egypt;
| | - Heba S. Elsewedy
- Department of Pharmaceutical Sciences, College of Clinical Pharmacy, King Faisal University, Al-Hofuf 36362, Saudi Arabia;
| | - Wafaa E. Soliman
- Department of Biomedical Sciences, College of Clinical Pharmacy, King Faisal University, Al-Hofuf 36362, Saudi Arabia;
- Department of Microbiology and Immunology, Faculty of Pharmacy, Delta University for Science and Technology, Gamasa, Mansoura 11152, Egypt
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Lesot P, Gil RR, Berdagué P, Navarro-Vázquez A. Deuterium Residual Quadrupolar Couplings: Crossing the Current Frontiers in the Relative Configuration Analysis of Natural Products. J Nat Prod 2020; 83:3141-3148. [PMID: 32970418 DOI: 10.1021/acs.jnatprod.0c00745] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The determination of the 3D structure (configuration and preferred conformation) of complex natural and synthetic organic molecules is a long-standing but still challenging task for chemists, with various implications in pharmaceutical sciences whether or not these substances have specific bioactivities. Nuclear magnetic resonance (NMR) in aligning media, either lyotropic liquid crystals (LLCs) or polymer gels, in combination with molecular modeling is a unique framework for solving complex structural problems whose analytical wealth lies in the establishment of nonlocal structural correlations. As an alternative to the already well-established anisotropic NMR parameters, such as RDCs (residual dipolar couplings) and RCSAs (residual chemical shift anisotropies), it is shown here that deuterium residual quadrupolar couplings (2H-RQCs) can be extracted from 2H 2D-NMR spectra recorded at the natural abundance level in samples oriented in a homopolypeptide LLCs (poly-γ-benzyl-l-glutamate (PBLG)). These 2H-RQCs were successfully used to address nontrivial structural problems in organic molecules. The performance and scope of this new tool is examined for two natural chiral compounds of pharmaceutical interest (strychnine and artemisinin). This is the first report in which the 3D structure/relative configuration of complex bioactive molecules is unambiguously determined using only 2H-RQCs, which, in this case, are at 2H natural abundance.
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Affiliation(s)
- Philippe Lesot
- Université Paris-Saclay, UFR d'Orsay, RMN en Milieu Orienté, ICMMO, UMR CNRS 8182, Bât. 410, 15 rue du Doyen, Georges Poitou, F-91405 Orsay, France
- Centre National de la Recherche Scientifique (CNRS), 3 rue Michel Ange, F-75016 Paris, France
| | - Roberto R Gil
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Philippe Berdagué
- Université Paris-Saclay, UFR d'Orsay, RMN en Milieu Orienté, ICMMO, UMR CNRS 8182, Bât. 410, 15 rue du Doyen, Georges Poitou, F-91405 Orsay, France
| | - Armando Navarro-Vázquez
- Departamento de Química Fundamental, Universidade Federal de Pernambuco, Cidade Universitária, CEP 50.740-540 Recife, Pernambuco, Brazil
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Nouleho Ilemo S, Barth D, David O, Quessette F, Weisser MA, Watel D. Improving graphs of cycles approach to structural similarity of molecules. PLoS One 2019; 14:e0226680. [PMID: 31881046 PMCID: PMC6934298 DOI: 10.1371/journal.pone.0226680] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Accepted: 12/03/2019] [Indexed: 12/02/2022] Open
Abstract
This paper focuses on determining the structural similarity of two molecules, i.e., the similarity of the interconnection of all the elementary cycles in the corresponding molecular graphs. In this paper, we propose and analyze an algorithmic approach based on the resolution of the Maximum Common Edge Subgraph (MCES) problem with graphs representing the interaction of cycles molecules. Using the ChEBI database, we compare the effectiveness of this approach in terms of structural similarity and computation time with two calculations of similarity of molecular graphs, one based on the MCES, the other on the use of different fingerprints (Daylight, ECFP4, ECFP6, FCFP4, FCFP6) to measure Tanimoto coefficient. We also analyze the obtained structural similarity results for a selected subset of molecules.
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Affiliation(s)
- Stefi Nouleho Ilemo
- DAVID, Department of Computer Science, University of Versailles Saint Quentin, Versailles, France
| | - Dominique Barth
- DAVID, Department of Computer Science, University of Versailles Saint Quentin, Versailles, France
| | - Olivier David
- ILV, Department of Chemistry, University of Versailles, Versailles, France
| | - Franck Quessette
- DAVID, Department of Computer Science, University of Versailles Saint Quentin, Versailles, France
| | | | - Dimitri Watel
- ENSIIE, Evry, France
- SAMOVAR, Telecom SudParis, Evry, France
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Saeed M, Imran M, Baig MH, Kausar MA, Shahid S, Ahmad I. Virtual screening of natural anti-filarial compounds against glutathione-S-transferase of Brugia malayi and Wuchereria bancrofti. Cell Mol Biol (Noisy-le-grand) 2018; 64:69-73. [PMID: 30403598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Revised: 09/25/2018] [Accepted: 10/03/2018] [Indexed: 06/08/2023]
Abstract
Glutathione-S-transferase also referred as GST is one of the major detoxification enzymes in parasitic helminths. The crucial role played by GST in various chronic infections has been well reported. The dependence of nematodes on detoxification enzymes to maintain their survival within the host established the crucial role of GST in filariasis and other related diseases. Hence, this well-established role of GST in filariasis along with its greater nonhomology with its human counterpart makes it an important therapeutic drug target. Here in this study, we have tried to explore the inhibitory potential of some of the well-reported natural ant-filarial compounds against the GST from Wuchereria bancrofti (W.bancrofti) and Brugia malayi (B.malayi). In silico virtual screening, approach was used to screen the selected natural compounds against GST from W.bancrofti and B.malayi. On the basis of our results, here we are reporting some of the natural compounds which were found to be very effective against GSTs. Along with we have also revealed the characteristic of the active site of BmGST and WbGST and the role of important active site residues involve in the binding of natural compounds within the active site of GSTs. This information will oped doors for using natural compounds as anti-filarial therapy and will also be helpful for future drug discovery.
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Affiliation(s)
- Mohd Saeed
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, University of Hail, KSA
| | - Mohd Imran
- Department of Biophysics, All India Institute of Medical Sciences, Ansari nagar, New Delhi, 110029, India
| | - Mohd Hassan Baig
- Department of Medical Biotechnology, Yeungnam University, The Republic of Korea
| | - Mohd Adnan Kausar
- Department of Biochemistry, college of Medicine, University of Hail, KSA
| | - Sma Shahid
- Department of Biochemistry, college of Medicine, University of Hail, KSA
| | - Irfan Ahmad
- Department of Clinical Laboratory Science, College of Applied Medical Sciences, King Khalid University. Abha, KSA
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7
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Beaufay C, Ledoux A, Jansen O, Bordignon A, Zhao S, Teijaro CN, Andrade RB, Quetin-Leclercq J, Frédérich M. In vivo Antimalarial and Antitrypanosomal Activity of Strychnogucine B, a Bisindole Alkaloid from Strychnos icaja. Planta Med 2018; 84:881-885. [PMID: 29929205 DOI: 10.1055/a-0644-2723] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Strychnogucine B is a bisindole alkaloid previously isolated from Strychnos icaja that possesses promising in vitro antiplasmodial properties. This compound was synthesized in four steps from (-)-strychnine. As no acute toxicity was observed at the highest tested cumulative dose of 60 mg/kg, its in vivo antimalarial activity was determined intraperitoneally at 30 mg/kg/d in a Plasmodium berghei murine model. In the Peters's 4-d suppressive test, this alkaloid suppressed the parasitaemia by almost 36% on day 5 and 60% on day 7 compared to vehicle-treated mice. In addition to this interesting antimalarial activity, it showed moderate in vitro antitrypanosomal activity but no in vivo activity in an acute Trypanosoma brucei model. It was also inactive in vitro on Leishmania mexicana promastigotes. This highlights its selective antimalarial efficacy and leads to further investigation to assess its potential as new antimalarial lead compound.
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Affiliation(s)
- Claire Beaufay
- Pharmacognosy Research Group, Louvain Drug Research Institute, Université Catholique de Louvain, Brussels, Belgium
| | - Allison Ledoux
- Laboratory of Pharmacognosy, CIRM, Université de Liège, Liège, Belgium
| | - Olivia Jansen
- Laboratory of Pharmacognosy, CIRM, Université de Liège, Liège, Belgium
| | | | - Senzhi Zhao
- Department of Chemistry, Temple University, Philadelphia, PA, United States of America
| | - Christiana N Teijaro
- Department of Chemistry, Temple University, Philadelphia, PA, United States of America
| | - Rodrigo B Andrade
- Department of Chemistry, Temple University, Philadelphia, PA, United States of America
| | - Joëlle Quetin-Leclercq
- Pharmacognosy Research Group, Louvain Drug Research Institute, Université Catholique de Louvain, Brussels, Belgium
| | - Michel Frédérich
- Laboratory of Pharmacognosy, CIRM, Université de Liège, Liège, Belgium
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8
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Tarenzi T, Calandrini V, Potestio R, Giorgetti A, Carloni P. Open Boundary Simulations of Proteins and Their Hydration Shells by Hamiltonian Adaptive Resolution Scheme. J Chem Theory Comput 2017; 13:5647-5657. [PMID: 28992702 DOI: 10.1021/acs.jctc.7b00508] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The recently proposed Hamiltonian adaptive resolution scheme (H-AdResS) allows the performance of molecular simulations in an open boundary framework. It allows changing, on the fly, the resolution of specific subsets of molecules (usually the solvent), which are free to diffuse between the atomistic region and the coarse-grained reservoir. So far, the method has been successfully applied to pure liquids. Coupling the H-AdResS methodology to hybrid models of proteins, such as the molecular mechanics/coarse-grained (MM/CG) scheme, is a promising approach for rigorous calculations of ligand binding free energies in low-resolution protein models. Toward this goal, here we apply for the first time H-AdResS to two atomistic proteins in dual-resolution solvent, proving its ability to reproduce structural and dynamic properties of both the proteins and the solvent, as obtained from atomistic simulations.
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Affiliation(s)
- Thomas Tarenzi
- Computation-Based Science and Technology Research Center CaSToRC, The Cyprus Institute , 20 Konstantinou Kavafi Street, 2121, Aglantzia, Nicosia, Cyprus
- Department of Physics, Faculty of Mathematics, Computer Science and Natural Sciences, Aachen University , Otto-Blumenthal-Straße, 52074 Aachen, Germany
| | - Vania Calandrini
- Computational Biomedicine, Institute for Advanced Simulation IAS-5, and Institute of Neuroscience and Medicine INM-9, Forschungszentrum Jülich , 52425 Jülich, Germany
| | - Raffaello Potestio
- Max Planck Institute for Polymer Research , Ackermannweg 10, 55128 Mainz, Germany
| | - Alejandro Giorgetti
- Computational Biomedicine, Institute for Advanced Simulation IAS-5, and Institute of Neuroscience and Medicine INM-9, Forschungszentrum Jülich , 52425 Jülich, Germany
- Department of Biotechnology, University of Verona , Ca' Vignal 1, Strada Le Grazie 15, 37134 Verona, Italy
| | - Paolo Carloni
- Department of Physics, Faculty of Mathematics, Computer Science and Natural Sciences, Aachen University , Otto-Blumenthal-Straße, 52074 Aachen, Germany
- Computational Biomedicine, Institute for Advanced Simulation IAS-5, and Institute of Neuroscience and Medicine INM-9, Forschungszentrum Jülich , 52425 Jülich, Germany
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9
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Verma K, Kannan K, V S, R S, V K, K R. Exploring β-Tubulin Inhibitors from Plant Origin using Computational Approach. Phytochem Anal 2017; 28:230-241. [PMID: 28008675 DOI: 10.1002/pca.2665] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Revised: 10/24/2016] [Accepted: 10/24/2016] [Indexed: 05/28/2023]
Abstract
INTRODUCTION β-Tubulin is an important target for the binding of anti-cancer drugs, in particular, paclitaxel (taxol), vinblastine and epothilone. However, mutations in β-tubulin structure give resistance to chemotherapeutic agents. Notably, mutations at R306C, F270 V, L217R, L228F, A185T and A248V positions in β-tubulin give high resistance for paclitaxel binding. OBJECTIVE To discover novel inhibitors of β-tubulin from natural sources, particularly alkaloids, using a virtual screening approach. METHODOLOGY A virtual screening approach was employed to find potent lead molecules from the Naturally-occurring Plant-based Anti-cancer Compound-activity Target (NPACT) database. Alkaloids have great potential to be anti-cancer agents. Therefore, we have screened all alkaloids from a total of 1574 molecules from the NPACT database for our study. Initially, Molinspiration and DataWarrior programs were utilised to calculate pharmacokinetics and toxicity risks of the alkaloids, respectively. Subsequently, AutoDock algorithm was employed to understand the binding efficiency of alkaloids against β-tubulin. The binding affinity of the docked complex was confirmed by means of an intermolecular interaction study. Moreover, oral toxicity was predicted by using ProTox program. Further, metabolising capacity of drugs was studied by using SmartCYP software. Additionally, scaffold analysis was done with the help of scaffold trees and dendrograms, providing knowledge about the building blocks for parent-compound synthesis. RESULTS Overall, the results of our computational analysis indicate that isostrychnine, obtained from Strychnosnux-vomica, satisfies pharmacokinetic and bioavailability properties, binds efficiently with β-tubulin. Thus, it could be a promising lead for the treatment of paclitaxel resistant cancer types. CONCLUSION This is the first observation of inhibitory activity of isostrychnine against β-tubulin and warrants further experimental investigation. Copyright © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
- Kanika Verma
- Department of Biotechnology, School of Bio Sciences and Technology, VIT University, Vellore, 632014, Tamil Nadu, India
| | - Kaavya Kannan
- Department of Biotechnology, School of Bio Sciences and Technology, VIT University, Vellore, 632014, Tamil Nadu, India
| | - Shanthi V
- Department of Biotechnology, School of Bio Sciences and Technology, VIT University, Vellore, 632014, Tamil Nadu, India
| | - Sethumadhavan R
- Department of Biotechnology, School of Bio Sciences and Technology, VIT University, Vellore, 632014, Tamil Nadu, India
| | - Karthick V
- School of Chinese Medicine, Hong Kong Baptist University, Hong Kong
| | - Ramanathan K
- Department of Biotechnology, School of Bio Sciences and Technology, VIT University, Vellore, 632014, Tamil Nadu, India
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Mohsen AMY, Mandour YM, Sarukhanyan E, Breitinger U, Villmann C, Banoub MM, Breitinger HG, Dandekar T, Holzgrabe U, Sotriffer C, Jensen AA, Zlotos DP. Oxime Ethers of (E)-11-Isonitrosostrychnine as Highly Potent Glycine Receptor Antagonists. J Nat Prod 2016; 79:2997-3005. [PMID: 27966945 DOI: 10.1021/acs.jnatprod.6b00479] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
A series of (E)-11-isonitrosostrychnine oxime ethers, 2-aminostrychnine, (strychnine-2-yl)propionamide, 18-oxostrychnine, and N-propylstrychnine bromide were synthesized and evaluated pharmacologically at human α1 and α1β glycine receptors in a functional fluorescence-based and a whole-cell patch-clamp assay and in [3H]strychnine binding studies. 2-Aminostrychnine and the methyl, allyl, and propargyl oxime ethers were the most potent α1 and α1β antagonists in the series, displaying IC50 values similar to those of strychnine at the two receptors. Docking experiments to the strychnine binding site of the crystal structure of the α3 glycine receptor indicated the same orientation of the strychnine core for all analogues. For the most potent oxime ethers, the ether substituent was accommodated in a lipophilic receptor binding pocket. The findings identify the oxime hydroxy group as a suitable attachment point for linking two strychnine pharmacophores by a polymethylene spacer and are, therefore, important for the design of bivalent ligands targeting glycine receptors.
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Affiliation(s)
- Amal M Y Mohsen
- Faculty of Pharmacy and Biotechnology, The German University in Cairo , New Cairo City, 11835 Cairo, Egypt
| | - Yasmine M Mandour
- Faculty of Pharmacy and Biotechnology, The German University in Cairo , New Cairo City, 11835 Cairo, Egypt
| | | | - Ulrike Breitinger
- Faculty of Pharmacy and Biotechnology, The German University in Cairo , New Cairo City, 11835 Cairo, Egypt
| | - Carmen Villmann
- Institute of Clinical Neurobiology, University of Würzburg , 97078 Würzburg, Germany
| | - Maha M Banoub
- Faculty of Pharmacy and Biotechnology, The German University in Cairo , New Cairo City, 11835 Cairo, Egypt
| | - Hans-Georg Breitinger
- Faculty of Pharmacy and Biotechnology, The German University in Cairo , New Cairo City, 11835 Cairo, Egypt
| | | | | | | | - Anders A Jensen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen , DK-2100 Copenhagen, Denmark
| | - Darius P Zlotos
- Faculty of Pharmacy and Biotechnology, The German University in Cairo , New Cairo City, 11835 Cairo, Egypt
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11
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Boros S, Batta G. Offset-compensated and zero-quantum suppressed ROESY provides accurate 1 H- 1 H distances in small to medium-sized molecules. Magn Reson Chem 2016; 54:947-952. [PMID: 27432252 DOI: 10.1002/mrc.4474] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Revised: 05/27/2016] [Accepted: 06/21/2016] [Indexed: 06/06/2023]
Abstract
A robust version of the off-resonance ROESY pulse scheme is suggested for the measurement of proton-proton distances or slow chemical exchange in small to medium-sized molecules. The method implements adiabatic ramps to establish a pair of opposite frequency off-resonance spin lock fields - with optionally randomized duration - and adiabatic inversion pulses with simultaneous gradients for efficient zero-quantum suppression. The amended pulse sequence yields pure absorption cross-peaks and works safely for small to medium-sized molecules. The applicability of the method has been demonstrated using small, rigid molecules (strychnine and codeine) and was also applied for a cyclic peptide and a small protein. We found that the pure phase cross-peaks of the new ROESY version are beneficial for distance measurements. The one-dimensional (selective) version of the new method is also powerful for measuring selected pair-wise interactions and distance determination. Copyright © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
| | - Gyula Batta
- Department of Organic Chemistry, Faculty of Science and Technology, University of Debrecen, Debrecen, Hungary
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Liu L, Song CW, Khan A, Li XN, Yang XW, Cheng GG, Liu YP, Luo XD. A potent antibacterial indole alkaloid from Psychotria pilifera. J Asian Nat Prod Res 2016; 18:798-803. [PMID: 26963582 DOI: 10.1080/10286020.2016.1158710] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Accepted: 02/23/2016] [Indexed: 06/05/2023]
Abstract
A new strychnine alkaloid, 16,17,19,20-tetrahydro-2,16-dehydro-18-deoxyisostrychnine (1), and fourteen known alkaloids were isolated from the leaves of Psychotria pilifera. Their structures were identified on the basis of extensive spectroscopic analysis, as well as by comparison with the reported spectroscopic data. The new alkaloid (1) exhibited potent antibacterial activity against Escherichia coli, equivalent to cefotaxime with MIC value of 0.781 μg/ml.
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Affiliation(s)
- Lu Liu
- a State Key Laboratory of Phytochemistry and Plant Resources in West China , Kunming Institute of Botany, Chinese Academy of Sciences , Kunming 650201 , China
- c University of Chinese Academy of Sciences , Beijing 100049 , China
| | - Chang-Wei Song
- a State Key Laboratory of Phytochemistry and Plant Resources in West China , Kunming Institute of Botany, Chinese Academy of Sciences , Kunming 650201 , China
| | - Afsar Khan
- a State Key Laboratory of Phytochemistry and Plant Resources in West China , Kunming Institute of Botany, Chinese Academy of Sciences , Kunming 650201 , China
- b Department of Chemistry , COMSATS Institute of Information Technology , Abbottabad 22060 , Pakistan
| | - Xiao-Ning Li
- a State Key Laboratory of Phytochemistry and Plant Resources in West China , Kunming Institute of Botany, Chinese Academy of Sciences , Kunming 650201 , China
| | - Xing-Wei Yang
- a State Key Laboratory of Phytochemistry and Plant Resources in West China , Kunming Institute of Botany, Chinese Academy of Sciences , Kunming 650201 , China
| | - Gui-Guang Cheng
- a State Key Laboratory of Phytochemistry and Plant Resources in West China , Kunming Institute of Botany, Chinese Academy of Sciences , Kunming 650201 , China
| | - Ya-Ping Liu
- a State Key Laboratory of Phytochemistry and Plant Resources in West China , Kunming Institute of Botany, Chinese Academy of Sciences , Kunming 650201 , China
| | - Xiao-Dong Luo
- a State Key Laboratory of Phytochemistry and Plant Resources in West China , Kunming Institute of Botany, Chinese Academy of Sciences , Kunming 650201 , China
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Mulders WHAM, Spencer TC, Robertson D. Effects of pulsatile electrical stimulation of the round window on central hyperactivity after cochlear trauma in guinea pig. Hear Res 2016; 335:128-137. [PMID: 26970475 DOI: 10.1016/j.heares.2016.03.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Revised: 02/09/2016] [Accepted: 03/03/2016] [Indexed: 11/17/2022]
Abstract
Partial hearing loss induced by acoustic trauma has been shown in animal models to result in an increased spontaneous firing rate in central auditory structures. This so-called hyperactivity has been suggested to be involved in the generation of tinnitus, a phantom auditory sensation. Although there is no universal cure for tinnitus, electrical stimulation of the cochlea, as achieved by a cochlear implant, can result in significant reduction of the tinnitus percept. However, the mechanism by which this tinnitus suppression occurs is as yet unknown and furthermore cochlear implantation may not be an optimal treatment option for tinnitus sufferers who are not profoundly deaf. A better understanding of the mechanism of tinnitus suppression by electrical stimulation of the cochlea, may lead to the development of more specialised devices for those for whom a cochlear implant is not appropriate. This study aimed to investigate the effects of electrical stimulation in the form of brief biphasic shocks delivered to the round window of the cochlea on the spontaneous firing rates of hyperactive inferior colliculus neurons following acoustic trauma in guinea pigs. Effects during the stimulation itself included both inhibition and excitation but spontaneous firing was suppressed for up to hundreds of ms after the cessation of the shock train in all sampled hyperactive neurons. Pharmacological block of olivocochlear efferent action on outer hair cells did not eliminate the prolonged suppression observed in inferior colliculus neurons, and it is therefore likely that activation of the afferent pathways is responsible for the central effects observed.
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Affiliation(s)
- W H A M Mulders
- The Auditory Laboratory, School of Anatomy, Physiology and Human Biology, The University of Western Australia, 35 Stirling Highway, Crawley WA 6009, Australia.
| | - T C Spencer
- The Auditory Laboratory, School of Anatomy, Physiology and Human Biology, The University of Western Australia, 35 Stirling Highway, Crawley WA 6009, Australia
| | - D Robertson
- The Auditory Laboratory, School of Anatomy, Physiology and Human Biology, The University of Western Australia, 35 Stirling Highway, Crawley WA 6009, Australia
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Li H, Hai J, Zhou J, Yuan G. Exploration of binding affinity and selectivity of brucine with G-quadruplex in the c-myb proto-oncogene by electrospray ionization mass spectrometry. Rapid Commun Mass Spectrom 2016; 30:407-414. [PMID: 26754134 DOI: 10.1002/rcm.7454] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2015] [Revised: 11/07/2015] [Accepted: 11/09/2015] [Indexed: 06/05/2023]
Abstract
RATIONALE The c-myb gene is a potential therapeutic target for human tumors and leukemias. Active ingredients from natural products may be used as drugs in chemotherapy for human cancers. Here, electrospray ionization mass spectrometry (ESI-MS) was used to probe the formation and recognition of the G-quadruplex structure from the G-rich sequence that is found in the c-myb gene promoter, 5'-GGGCTGGGCTGGGCGGGG-3'. The aim of our study is to evaluate a potential binder for the c-myb gene from natural products, and thereby to modulate c-myb gene expression. METHODS ESI-MS, as an effective method, was utilized not only to characterize the formation of the G-quadruplex in the c-myb oncogene, but also as a tool to probe the binding characteristics of alkaloid molecules with the target G-quadruplex DNA. RESULTS ESI-MS results with the support of circular dichroism (CD) spectra demonstrated the formation of an intramolecular parallel-stranded G-quadruplex in the c-myb oncogene promoter. A screening of six alkaloid molecules showed that brucine (P1) had a strong binding affinity to the c-myb G-quadruplex DNA. It is notable that P1 can bind selectively to the c-myb G-quadruplex with respect to duplex DNAs, as well as to G-quadruplexes in other types of gene sequences. According to ESI-MS results, in which the stability was tested by capillary heating and collision-induced dissociation, the binding of P1 could thermally stabilize the c-myb G-quadruplex DNA. CONCLUSIONS In this work, brucine (P1), an alkaloid molecule, has been found to bind to the intramolecular parallel G-quadruplex in the c-myb oncogene promoter with high affinity and selectivity, and could thermally stabilize the c-myb G-quadruplex DNA, indicating that the binding of P1 has the potential to modulate c-myb gene expression. Copyright © 2015 John Wiley & Sons, Ltd.
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Affiliation(s)
- Huihui Li
- National and Local Joint Engineering Research Center of Biomedical Functional Materials, Jiangsu Collaborative Innovation Center of Biomedical Functional Materials, College of Chemistry and Materials Science, Nanjing Normal University, Nanjing, 210023, China
| | - Jinhui Hai
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, Department of Chemical Biology, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China
- National and Local Joint Engineering Research Center of Biomedical Functional Materials, Jiangsu Collaborative Innovation Center of Biomedical Functional Materials, College of Chemistry and Materials Science, Nanjing Normal University, Nanjing, 210023, China
| | - Jiang Zhou
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, Department of Chemical Biology, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China
| | - Gu Yuan
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, Department of Chemical Biology, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China
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Saurí J, Frédérich M, Tchinda AT, Parella T, Williamson RT, Martin GE. Carbon Multiplicity Editing in Long-Range Heteronuclear Correlation NMR Experiments: A Valuable Tool for the Structure Elucidation of Natural Products. J Nat Prod 2015; 78:2236-2241. [PMID: 26305494 DOI: 10.1021/acs.jnatprod.5b00447] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
A recently developed NMR method to simultaneously obtain both long-range heteronuclear correlations and carbon multiplicity information in a single experiment, ME-selHSQMBC, is demonstrated as a potentially useful technique for chemical shift assignment and structure elucidation of natural products presenting complicated NMR spectra. Carbon multiplicities, even for C/CH2 and odd for CH/CH3 resonances, can be distinguished directly from the relative positive/negative phase of cross-peaks. In addition, connectivity networks can be further extended by incorporating a TOCSY propagation step. Staurosporine (1) and sungucine (2) are utilized as model compounds to demonstrate these techniques.
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Affiliation(s)
- Josep Saurí
- NMR Structure Elucidation, Process and Analytical Chemistry, Merck & Co. Inc. , Rahway, New Jersey 07065, United States
| | - Michel Frédérich
- Laboratory of Pharmacognosy, Department of Pharmacy, CIRM, University of Liège , B36, 4000 Liège, Belgium
| | - Alembert T Tchinda
- Center for Studies on Medicinal Plants and Traditional Medicine, Institute of Medical Research and Medicinal Plants Studies (IMPM) , P.O. Box 6163, Yaoundé, Cameroon
| | - Teodor Parella
- Servei de Ressonància Magnètica Nuclear, Universitat Autònoma de Barcelona , E-08193 Bellaterra, Barcelona, Spain
| | - R Thomas Williamson
- NMR Structure Elucidation, Process and Analytical Chemistry, Merck & Co. Inc. , Rahway, New Jersey 07065, United States
| | - Gary E Martin
- NMR Structure Elucidation, Process and Analytical Chemistry, Merck & Co. Inc. , Rahway, New Jersey 07065, United States
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Islam N, Niaz S, Manzoor T, Pandith AH. Theoretical investigations into spectral and non-linear optical properties of brucine and strychnine using density functional theory. Spectrochim Acta A Mol Biomol Spectrosc 2014; 131:461-470. [PMID: 24840487 DOI: 10.1016/j.saa.2014.04.089] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Revised: 04/03/2014] [Accepted: 04/13/2014] [Indexed: 06/03/2023]
Abstract
The density functional theoretical (DFT) computations were performed at the B3LYP/6-311G++(d, p) level to calculate the equilibrium geometry, vibrational wave numbers, intensities, and various other molecular properties of brucine and strychnine, which were found in satisfactory agreement with the experimental data. The out-of-phase stretching modes of aromatic rings and carbonyl stretching modes in combination with CH stretching modes at stereogenic centers generate VCD signals, which are remarkably efficient configuration markers for these chiral molecular systems. NBOs analysis reveals that the large values of second order perturbation energy (47.24kcal/mol for brucine and 46.93kcal/mol for strychnine) confirms strong hyperconjugative interaction between the orbital containing the lone pair of electron of nitrogen and the neighboring CO antibonding orbital. The molecular electrostatic potential map of strychnine molecule, with no polar groups other than the lone keto group, shows less polarization, which accounts for its lower susceptibility towards electrophilic attack as compared to brucine.
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Affiliation(s)
- Nasarul Islam
- Department of Chemistry, University of Kashmir, Srinagar 190006, J&K, India
| | - Saba Niaz
- Department of Chemistry, University of Kashmir, Srinagar 190006, J&K, India
| | - Taniya Manzoor
- Department of Chemistry, University of Kashmir, Srinagar 190006, J&K, India
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Buevich AV, Williamson RT, Martin GE. NMR Structure Elucidation of Small Organic Molecules and Natural Products: Choosing ADEQUATE vs HMBC. J Nat Prod 2014; 77:1942-1947. [PMID: 25098228 DOI: 10.1021/np500445s] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Long-range heteronuclear shift correlation methods have served as the cornerstone of modern structure elucidation protocols for several decades. The (1)H-(13)C HMBC experiment provides a versatile and relatively sensitive means of establishing predominantly (3)J(CH) connectivity with the occasional (2)J(CH) or (4)J(CH) correlation being observed. The two-bond and four-bond outliers must be identified specifically to avoid spectral and/or structural misassignment. Despite the versatility and extensive applications of the HMBC experiment, it can still fail to elucidate structures of molecules that are highly proton-deficient, e.g., those that fall under the so-called "Crews rule". In such cases, recourse to the ADEQUATE experiments should be considered. Thus, a study was undertaken to facilitate better investigator understanding of situations where it might be beneficial to apply 1,1- or 1,n-ADEQUATE to proton-rich or proton-deficient molecules. Equipped with a better understanding of when a given experiment might be more likely to provide the necessary correlation data, investigators can make better decisions on when it might be advisible to employ one experiment over the other. Strychnine (1) and cervinomycin A2 (2) were employed as model compounds to represent proton-rich and proton-deficient classes of molecules, respectively. DFT methods were employed to calculate the relevant (n)J(CH) heteronuclear proton-carbon and (n)J(CC) homonuclear carbon-carbon coupling constants for this study.
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Affiliation(s)
- Alexei V Buevich
- Discovery and Preclinical Sciences, Process and Analytical Chemistry, NMR Structure Elucidation, Merck Research Laboratories , Kenilworth, New Jersey 07033, United States
| | - R Thomas Williamson
- Discovery and Preclinical Sciences, Process and Analytical Chemistry, NMR Structure Elucidation, Merck Research Laboratories , Rahway, New Jersey 07065, United States
| | - Gary E Martin
- Discovery and Preclinical Sciences, Process and Analytical Chemistry, NMR Structure Elucidation, Merck Research Laboratories , Rahway, New Jersey 07065, United States
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Tchinda AT, Jansen O, Nyemb JN, Tits M, Dive G, Angenot L, Frédérich M. Strychnobaillonine, an unsymmetrical bisindole alkaloid with an unprecedented skeleton from Strychnos icaja roots. J Nat Prod 2014; 77:1078-1082. [PMID: 24593048 DOI: 10.1021/np400908u] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
A reinvestigation of the roots of Strychnos icaja resulted in the isolation of a new bisindole alkaloid named strychnobaillonine (1) with original C-17-N-1' and C-23-C-17' junctions, in addition to sungucine, bisnordihydrotoxiferine, and strychnohexamine (2). Compound 1 showed potent activity against the chloroquine-sensitive 3D7 strain of Plasmodium falciparum in vitro with an IC50 value of 1.1 μM. The structures of the compounds were defined by detailed spectroscopic analyses, especially 1H and 13C NMR, DEPT, HSQC, COSY, NOESY, HMBC, and HRESIMS. The proposed absolute configuration was based on biosynthetic considerations and spectroscopic data (CD, NMR) supported by molecular modeling.
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Affiliation(s)
- Alembert T Tchinda
- Center for Studies on Medicinal Plants and Traditional Medicine, Institute of Medical Research and Medicinal Plants Studies (IMPM) , P.O. Box 6163, Yaoundé, Cameroon
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Chen J, He CQ, Lin AH, Xu F, Wang F, Zhao B, Liu X, Chen ZP, Cai BC. Brucine-loaded liposomes composed of HSPC and DPPC at different ratios: in vitro and in vivo evaluation. Drug Dev Ind Pharm 2014; 40:244-51. [PMID: 23600656 DOI: 10.3109/03639045.2012.756009] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
OBJECTIVE The objective of this study is to test the hypothesis that the phase transition temperature (T(m)), the main property of liposomes, can be easily controlled by changing the molar ratio of hydrogenated soy phosphatidylcholine (HSPC) and 1,2-dipalmitoyl-sn-glycero-3-phosphacholine (DPPC) after drug encapsulation. MATERIALS AND METHODS Brucine, an antitumor alkaloid, was encapsulated into the liposomes with different HSPC/DPPC compositions. The T(m)s of the brucine-loaded liposomes (BLs) were determined by differential scanning calorimetry (DSC). Then the physicochemical properties and pharmacokinetics of the BLs with different HSPC/DPPC compositions were investigated and compared. RESULTS The results of DSC revealed that HSPC and DPPC can combine into one phase. The findings of molecular modeling study suggested that HSPC interacts with DPPC via electrostatic interaction. The molar ratio of HSPC/DPPC influenced the sizes of BLs but had little effect on the entrapment efficiency (EE). The stability of BLs was improved with the increase of the HSPC ratios, especially with the presence of plasma. Following i.v. administration, it was found that AUC values of BLs in vivo were directly related to the HSPC/DPPC ratios of BLs, namely the T(m)s of BLs. DISCUSSION The behavior of liposomes, especially in vivo pharmacokinetic behavior, can be controlled by the modification of T(m). CONCLUSION The characterization of BLs in vitro and in vivo had demonstrated that the Tm could be flexibly modified for liposomes composed of both HSPC and DPPC. Using HSPC/DPPC composition may be an efficient strategy to control the T(m), thus control the in vivo pharmacokinetic behavior, of BLs.
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Affiliation(s)
- Jun Chen
- National First-Class Key Discipline for Traditional Chinese Medicine, Nanjing University of Chinese Medicine , Nanjing , P.R. China
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Senior MM, Williamson RT, Martin GE. Using HMBC and ADEQUATE NMR data to define and differentiate long-range coupling pathways: is the Crews rule obsolete? J Nat Prod 2013; 76:2088-2093. [PMID: 24195498 DOI: 10.1021/np400562u] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
It is well known that as molecules become progressively more proton-deficient, structure elucidation becomes correspondingly more challenging. When the ratio of (1)H to (13)C and the sum of other heavy atoms falls below 2, an axiom that has been dubbed the "Crews rule" comes into play. The general premise of the Crews rule is that highly proton-deficient molecules may have structures that are difficult, and in some cases impossible, to elucidate using conventional suites of NMR experiments that include proton and carbon reference spectra, COSY, multiplicity-edited HSQC, and HMBC (both (1)H-(13)C and (1)H-(15)N). However, with access to modern cryogenic probes and microcyroprobes, experiments that have been less commonly utilized in the past and new experiments such as inverted (1)J(CC) 1,n-ADEQUATE are feasible with modest sized samples. In this light, it may well be time to consider revising the Crews rule. The complex, highly proton-deficient alkaloid staurosporine (1) is used as a model proton-deficient compound for this investigation to highlight the combination of inverted (1)J(CC) 1,n-ADEQUATE with 1.7 mm cryoprobe technology.
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Affiliation(s)
- Mary M Senior
- Discovery and Preclinical Sciences, Process and Analytical Chemistry, Structural Elucidation Group, Merck Research Laboratories , Kenilworth, New Jersey 07033, United States
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Saraswati S, Alhaider AA, Agrawal SS. Anticarcinogenic effect of brucine in diethylnitrosamine initiated and phenobarbital-promoted hepatocarcinogenesis in rats. Chem Biol Interact 2013; 206:214-21. [PMID: 24060683 DOI: 10.1016/j.cbi.2013.09.012] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2013] [Revised: 08/30/2013] [Accepted: 09/13/2013] [Indexed: 12/12/2022]
Abstract
We evaluated the effects of brucine on N-nitrosodiethylamine (DENA)-induced hepatocarcinogenesis in rats. Initiation of hepatocarcinogenesis was done by intraperitoneal injection of diethylnitrosamine (DENA) followed by promotion with phenobarbital. The rats were exposed to dietary brucine for 4 weeks prior to initiation, and the treatment was continued for 22 consecutive weeks. Brucine decreased the incidence, total number, multiplicity, size and volume of preneoplastic hepatic nodules in a dose-dependent manner. Administration of DENA induced hepatocellular carcinoma (HCC), as evidenced by changes in histopathological architecture, increased activity of cytochrome P450, decreased activity of glutathione Stransferase (GST) as well as decreased antioxidant status, enhanced lipid peroxidation, increased liver marker enzymes. Western blot analysis showed decreased expression of cyclin D1 and Bcl-2 with activation of caspase-3 and increased expression of Bax. Immunohistochemical demonstrated the decreased expression of the PCNA and VEGF. These results indicate that brucine prevents lipid peroxidation and hepatic cell damage and also protects the antioxidant system in DENA-induced hepatocarcinogenesis.
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Affiliation(s)
- Sarita Saraswati
- Camel Biomedical Research Unit, College of Pharmacy and Medicine, King Saud University, Riyadh, Saudi Arabia.
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Martin GE, Blinov KA, Williamson RT. HMBC-1,n-ADEQUATE spectra calculated from HMBC and 1,n-ADEQUATE spectra. Magn Reson Chem 2013; 51:299-307. [PMID: 23483673 DOI: 10.1002/mrc.3946] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2012] [Revised: 01/30/2013] [Accepted: 02/06/2013] [Indexed: 06/01/2023]
Abstract
Unsymmetrical and generalized indirect covariance processing methods provide a means of mathematically combining pairs of 2D NMR spectra that share a common frequency domain to facilitate the extraction of correlation information. Previous reports have focused on the combination of HSQC spectra with 1,1-, 1,n-, and inverted (1)J(CC) 1,n-ADEQUATE spectra to afford carbon-carbon correlation spectra that allow the extraction of direct ((1)J(CC)), long-range ((n)J(CC), where n ≥ 2), and (1)J(CC)-edited long-range correlation data, respectively. Covariance processing of HMBC and 1,1-ADEQUATE spectra has also recently been reported, allowing convenient, high-sensitivity access to (n)J(CC) correlation data equivalent to the much lower sensitivity n,1-ADEQUATE experiment. Furthermore, HMBC-1,1-ADEQUATE correlations are observed in the F1 frequency domain at the intrinsic chemical shift of the (13)C resonance in question rather than at the double-quantum frequency of the pair of correlated carbons, as visualized by the n,1, and m,n-ADEQUATE experiments, greatly simplifying data interpretation. In an extension of previous work, the covariance processing of HMBC and 1,n-ADEQUATE spectra is now reported. The resulting HMBC-1,n-ADEQUATE spectrum affords long-range carbon-carbon correlation data equivalent to the very low sensitivity m,n-ADEQUATE experiment. In addition to the significantly higher sensitivity of the covariance calculated spectrum, correlations in the HMBC-1,n-ADEQUATE spectrum are again detected at the intrinsic (13)C chemical shifts of the correlated carbons rather than at the double-quantum frequency of the pair of correlated carbons. HMBC-1,n-ADEQUATE spectra can provide correlations ranging from diagonal ((0)J(CC) or diagonal correlations) to (4)J(CC) under normal circumstances to as much as (6)J(CC) in rare instances. The experiment affords the potential means of establishing the structures of severely proton-deficient molecules.
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Affiliation(s)
- Gary E Martin
- Discovery and Preclinical Sciences, Process and Analytical Chemistry, Structure Elucidation Group, Merck Research Laboratories, Summit, NJ 07901, USA.
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Metaxas AE, Cort JR. Counterion influence on chemical shifts in strychnine salts. Magn Reson Chem 2013; 51:292-298. [PMID: 23495106 DOI: 10.1002/mrc.3945] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2012] [Revised: 01/04/2013] [Accepted: 02/05/2013] [Indexed: 06/01/2023]
Abstract
The highly toxic plant alkaloid strychnine is often isolated in the form of the anion salt of its protonated tertiary amine. Here, we characterize the relative influence of different counterions on (1)H and (13)C chemical shifts in several strychnine salts in D2O, methanol-d4 (CD3OD), and chloroform-d (CDCl3) solvents. In organic solvents but not in water, substantial variation in chemical shifts of protons near the tertiary amine was observed among different salts. These secondary shifts reveal differences in the way each anion influences electronic structure within the protonated amine. The distributions of secondary shifts allow salts to be easily distinguished from each other as well as from the free base form. Slight concentration dependence in chemical shifts of some protons near the amine was observed for two salts in CDCl3, but this effect is small compared with the influence of the counterion. Distinct chemical shifts in different salt forms of the same compound may be useful as chemical forensic signatures for source attribution and sample matching of alkaloids such as strychnine and possibly other organic acid and base salts.
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Affiliation(s)
- Athena E Metaxas
- Fundamental and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA 99352, USA
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Saurí J, Parella T. Efficient measurement of the sign and the magnitude of long-range proton-carbon coupling constants from a spin-state-selective HSQMBC-COSY experiment. Magn Reson Chem 2012; 50:717-721. [PMID: 22949157 DOI: 10.1002/mrc.3867] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2012] [Revised: 07/04/2012] [Accepted: 08/06/2012] [Indexed: 06/01/2023]
Abstract
A spin state-selective Heteronuclear Single-Quantum Multiple-Bond Connectivities (HSQMBC-COSY) experiment is proposed to measure the sign and the magnitude of long-range proton-carbon coupling constants ((n)J(CH); n > 1) either for protonated or for non-protonated carbons in small molecules. The simple substitution of the selective 180° (1)H pulse in the original selHSQMBC pulse scheme by a hard one allows the simultaneous evolution of both proton-proton and proton-carbon coupling constants during the refocusing period and enables a final COSY transfer between coupled protons. The successful implementation of the IPAP principle leads to separate mixed-phase α/β cross-peaks from which (n)J(CH) values can be easily measured by analyzing their relative frequency displacements in the detected dimension.
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Affiliation(s)
- Josep Saurí
- Servei de Ressonància Magnètica Nuclear, Universitat Autònoma de Barcelona, E-08193-Bellaterra, Barcelona, Spain
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Martin GE, Williamson RT, Blinov KA, Anklin CG, Bermel W. HMBC-1,1-ADEQUATE via generalized indirect covariance: a high sensitivity alternative to n,1-ADEQUATE. Magn Reson Chem 2012; 50:691-695. [PMID: 22930548 DOI: 10.1002/mrc.3863] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2012] [Revised: 07/03/2012] [Accepted: 07/23/2012] [Indexed: 06/01/2023]
Abstract
1,1-ADEQUATE and the related long-range 1,n- and n,1-ADEQUATE variants were developed to provide an unequivocal means of establishing (2)J(CH) and the equivalent of (n)J(CH) correlations where n = 3,4. Whereas the 1,1- and 1,n-ADEQUATE experiments have two simultaneous evolution periods that refocus the chemical shift and afford net single quantum evolution for the carbon spins, the n,1-variant has a single evolution period that leaves the carbon spin to be observed at the double quantum frequency. The n,1-ADEQUATE experiment begins with an HMBC-type (n)J(CH) magnetization transfer, which leads to inherently lower sensitivity than the 1,1- and 1,n-ADEQUATE experiments that begin with a (1)J(CH) transfer. These attributes, in tandem, serve to render the n,1-ADEQUATE experiment less generally applicable and more difficult to interpret than the 1,n-ADEQUATE experiment, which can in principle afford the same structural information. Unsymmetrical and generalized indirect covariance processing methods can complement and enhance the structural information encoded in combinations of experiments e.g. HSQC-1,1- or -1,n-ADEQUATE. Another benefit is that covariance processing methods offer the possibility of mathematically combining a higher sensitivity 2D NMR spectrum with for example 1,1- or 1,n-ADEQUATE to improve access to the information content of lower sensitivity congeners. The covariance spectrum also provides a significant enhancement in the F(1) digital resolution. The combination of HMBC and 1,1-ADEQUATE spectra is shown here using strychnine as a model compound to derive structural information inherent to an n,1-ADEQUATE spectrum with higher sensitivity and in a more convenient to interpret single quantum presentation.
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Affiliation(s)
- Gary E Martin
- Discovery and Preclinical Sciences-Process & Analytical Chemistry, Merck Research Laboratories, Summit, NJ 07901, USA.
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Zhan LF, Liu MD, Yan YY, Ye Y, Wang W, Wang ZH, Zhao JH, Liao LC. [LC-MS/MS analysis of determination of strychnine and brucine in formaldehyde fixed tissue]. Fa Yi Xue Za Zhi 2012; 28:347-350. [PMID: 23213784] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
OBJECTIVE To establish a method for determination of strychnine and brucine in formaldehyde fixed tissue by LC-MS/MS analysis. METHODS The samples were pretreated with solid phase extraction using SCX cartridges and separated on SB-C18 column with mobile phase 0.1% formic acid : 0.1% formic acid-acetonitrile (75:25). Electrospray ionization (ESI) source was utilized and operated in positive ion mode. Multiple reactions monitoring (MRM) mode was applied. External standard method was applied for quantitation. RESULTS The chromatographic separation of strychnine and brucine in formaldehyde fixed nephritic and hepatic tissues resulted successfully. The standard curve was linear in the range of 0.002-2.0 microg/g for strychnine and brucine in formaldehyde fixed tissues, and the correlation coefficient was more than 0.996. The limits of detection (LOD) of strychnine and brucine in nephritic tissues were 0.06ng/g and 0.03 ng/g, respectively. The LOD of both chemicals were 0.3 ng/g in hepatic tissues. The extraction recovery rate was more than 74.5%. The precision of intra-day and inter-day were both less than 8.2%. CONCLUSION Strychnine and brucine can be sensitive to be determined in formaldehyde fixed tissue by LC-MS/MS analysis. It can be applied in the forensic toxicological analysis.
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Affiliation(s)
- Lan-fen Zhan
- West China School of Preclinical and Forensic Medicine, Sichuan University, Chengdu 610041, China.
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Chen ZP, Liu W, Chen HX, Cai BC. [Brucine chitosan thermosensitive hydrogel for intra-articular injection]. Yao Xue Xue Bao 2012; 47:652-656. [PMID: 22812012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The aim of this study was to develop a sustained release converse thermosensitive hydrogel for intra-articular injection using chitosan-glycerol-borax as matrix, its physical properties and biocompatibility were investigated. Taking gelation time and gelation condition as index, the influence of concentration of chitosan, ratio of chitosan to glycerol, pH on physical properties of hydrogel were investigated. And then the in vitro drug release, rheological properties and biocompatibility were studied. The thermosensitive hydrogel flows easily at room temperature and turns to gelation at body temperature, which can certainly prolong the release of drug and has good biocompatibility.
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Affiliation(s)
- Zhi-Peng Chen
- College of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210029, China.
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Cannon JS, Overman LE. Is there no end to the total syntheses of strychnine? Lessons learned in strategy and tactics in total synthesis. Angew Chem Int Ed Engl 2012; 51:4288-311. [PMID: 22431197 PMCID: PMC3804246 DOI: 10.1002/anie.201107385] [Citation(s) in RCA: 127] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2011] [Revised: 11/22/2011] [Indexed: 12/19/2022]
Abstract
From the 19th century to the present, the complex indole alkaloid strychnine has engaged the chemical community. In this Review, we examine why strychnine has been and remains today an important target for directed synthesis efforts. A selection of the diverse syntheses of strychnine is discussed with the aim of identifying their influence on the evolution of the strategy and tactics of organic synthesis.
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Affiliation(s)
- Jeffrey S. Cannon
- Department of Chemistry University of California, Irvine 1102 Natural Sciences II, Irvine, California 92697-2025 (USA)
| | - Larry E. Overman
- Department of Chemistry University of California, Irvine 1102 Natural Sciences II, Irvine, California 92697-2025 (USA)
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Behpour M, Ghoreishi SM, Khayatkashani M, Motaghedifard M. A new method for the simultaneous analysis of strychnine and brucine in Strychnos nux-vomica unprocessed and processed seeds using a carbon-paste electrode modified with multi-walled carbon nanotubes. Phytochem Anal 2012; 23:95-102. [PMID: 21618309 DOI: 10.1002/pca.1327] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2010] [Revised: 01/30/2011] [Accepted: 02/14/2011] [Indexed: 05/30/2023]
Abstract
INTRODUCTION Strychnos nux-vomica L. (Loganiaceae), widely used in folk medicine, is grown extensively in southern Asian countries. Its major bioactive constituents are strychnine and brucine, which are frequently used in traditional herbal medicines for treatment of nervous diseases, vomiting and traumatic pain. OBJECTIVE A new method using a carbon-paste electrode modified with multi-walled carbon nanotubes (CNT/CPE) was developed and validated for single or simultaneous determination of strychnine and brucine in Strychnos nux-vomica seeds. Additionally, an environmentally friendly method was successfully applied to reduce the levels of strychnine and brucine in seeds. MATERIALS AND METHODS Cyclic voltammetry, chronocoulometry and differential pulse voltammetry were used with multi-walled carbon nanotube modified carbon-paste electrodes. RESULTS The peak currents increase linearly with the strychnine and brucine concentrations in the ranges of 50-1000 and 5-355 µ m, and the detection limits for strychnine and brucine were 0.43 and 0.28 µ m, respectively. Of the processing methods used, the greatest reduction in the strychnine and brucine levels was observed in samples processed using milk and saltwater. CONCLUSION A new, sensitive and selective method was developed for the measurement of strychnine and brucine. This method was successfully applied to the determination of strychnine and brucine in unprocessed and processed Strychnos nux-vomica seed.
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Affiliation(s)
- Mohsen Behpour
- Department of Analytical Chemistry, Faculty of Chemistry, University of Kashan, Kashan, I.R., Iran.
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Gil S, Espinosa JF, Parella T. Accurate measurement of small heteronuclear coupling constants from pure-phase α/β HSQMBC cross-peaks. J Magn Reson 2011; 213:145-150. [PMID: 22005221 DOI: 10.1016/j.jmr.2011.09.036] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2011] [Revised: 09/01/2011] [Accepted: 09/15/2011] [Indexed: 05/31/2023]
Abstract
A simple proton-selective α/β-HSQMBC experiment is proposed for the accurate measurement of long-range proton-carbon coupling constants (nJCH) in small molecules without need for an individualized and time-consuming post-processing fitting procedure. The method acquires two pure-phase In-phase (IP) and Anti-phase (AP) multiplets completely free of any phase distortion due to the absence of JHH evolution. Accurate nJCH values can be directly measured analyzing the relative displacement of the resulting IPAP cross-peaks. Discussion about signal intensity dependence and cross-talk is made for a range of experimental conditions. The robustness of the method is evaluated by comparing the nJCH value measured from the analysis of the three available IP, AP and IPAP multiplet patterns. Multiple-frequency and region-selective versions of the method can also be efficiently recorded provided that excited protons are not mutually coupled.
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Affiliation(s)
- Sergi Gil
- Servei de Ressonància Magnètica Nuclear, Universitat Autònoma de Barcelona, E-08193 Bellaterra, Barcelona, Spain
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Martin GE, Hilton BD, Willcott MR, Blinov KA. HSQC-1,n-ADEQUATE: a new approach to long-range 13C-13C correlation by covariance processing. Magn Reson Chem 2011; 49:641-647. [PMID: 21915897 DOI: 10.1002/mrc.2793] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2011] [Revised: 06/14/2011] [Accepted: 06/24/2011] [Indexed: 05/31/2023]
Abstract
Long-range, two-dimensional heteronuclear shift correlation NMR methods play a pivotal role in the assembly of novel molecular structures. The well-established GHMBC method is a high-sensitivity mainstay technique, affording connectivity information via (n)J(CH) coupling pathways. Unfortunately, there is no simple way of determining the value of n and hence no way of differentiating two-bond from three- and occasionally four-bond correlations. Three-bond correlations, however, generally predominate. Recent work has shown that the unsymmetrical indirect covariance or generalized indirect covariance processing of multiplicity edited GHSQC and 1,1-ADEQUATE spectra provides high-sensitivity access to a (13)C-(13) C connectivity map in the form of an HSQC-1,1-ADEQUATE spectrum. Covariance processing of these data allows the 1,1-ADEQUATE connectivity information to be exploited with the inherent sensitivity of the GHSQC spectrum rather than the intrinsically lower sensitivity of the 1,1-ADEQUATE spectrum itself. Data acquisition times and/or sample size can be substantially reduced when covariance processing is to be employed. In an extension of that work, 1,n-ADEQUATE spectra can likewise be subjected to covariance processing to afford high-sensitivity access to the equivalent of (4)J(CH) GHMBC connectivity information. The method is illustrated using strychnine as a model compound.
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Affiliation(s)
- Gary E Martin
- Merck Research Laboratories, Discovery and Preclinical Sciences, Global Chemistry, Structure Elucidation Group, Summit, NJ 07901, USA.
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Martin GE, Hilton BD, Willcott MR, Blinov KA. HSQC-ADEQUATE: an investigation of data requirements. Magn Reson Chem 2011; 49:350-357. [PMID: 21452353 DOI: 10.1002/mrc.2757] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2011] [Revised: 02/14/2011] [Accepted: 02/23/2011] [Indexed: 05/30/2023]
Abstract
Utilizing (13)C-(13)C connectivity networks for the assembly of carbon skeletons from HSQC-ADEQUATE spectra was recently reported. HSQC-ADEQUATE data retain the resonance multiplicity information of the multiplicity-edited GHSQC spectrum and afford a significant improvement in the signal-to-noise (s/n) ratio relative to the 1,1-ADEQUATE data used in the calculation of the HSQC-ADEQUATE spectrum by unsymmetrical indirect covariance (UIC) processing methods. The initial investigation into the computation of HSQC-ADEQUATE correlation plots utilized overnight acquisition of the 1,1-ADEQUATE data used for the calculation. In this communication, we report the results of an investigation of the reduction in acquisition time for the 1,1-ADEQUATE data to take advantage of the s/n gain during the UIC processing to afford the final HSQC-ADEQUATE correlation plot. Data acquisition times for the 1,1-ADEQUATE spectrum can be reduced to as little as a few hours, while retaining excellent s/n ratios and all responses contained in spectra computed from overnight data acquisitions. Concatenation of multiplicity-edited GHSQC and 1,1-ADEQUATE data also allows the interrogation of submilligram samples with 1,1-ADEQUATE data when using spectrometers equipped with 1.7-mm Micro CryoProbes ™.
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Affiliation(s)
- Gary E Martin
- Merck Research Laboratories, Discovery and Preclinical Sciences-Global Chemistry, Structure Elucidation Group, Summit, NJ 07901, USA.
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Martin GE, Hilton BD, Blinov KA. HSQC-ADEQUATE correlation: a new paradigm for establishing a molecular skeleton. Magn Reson Chem 2011; 49:248-252. [PMID: 21400588 DOI: 10.1002/mrc.2743] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2010] [Revised: 01/05/2011] [Accepted: 01/27/2011] [Indexed: 05/30/2023]
Abstract
Various experimental methods have been developed to unequivocally identify vicinal neighbor carbon atoms. Variants of the HMBC experiment intended for this purpose have included 2J3J-HMBC and H2BC. The 1,1-ADEQUATE experiment, in contrast, was developed to accomplish the same goal but relies on the (1) J(CC) coupling between a proton-carbon resonant pair and the adjacent neighbor carbon. Hence, 1,1-ADEQUATE can identify non-protonated adjacent neighbor carbons, whereas the 2J3J-HMBC and H2BC experiments require both neighbor carbons to be protonated to operate. Since 1,1-ADEQUATE data are normally interpreted with close reference to an HSQC spectrum of the molecule in question, we were interested in exploring the unsymmetrical indirect covariance processing of multiplicity-edited GHSQC and 1,1-ADEQUATE spectra to afford an HSQC-ADEQUATE correlation spectrum that facilitates the extraction of carbon-carbon connectivity information. The HSQC-ADEQUATE spectrum of strychnine is shown and the means by which the carbon skeleton can be conveniently traced is discussed.
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Affiliation(s)
- Gary E Martin
- Merck Research Laboratories, Discovery and Preclinical Sciences, Chemical Process Research, Rapid Structure Characterization Laboratory, Summit, NJ 07901, USA.
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BARDHAN DK, CHAKRAVARTY D. Method for the Quantitative Estimation of Strychnine and Brucine in Nux Vomica by Paper Electrophoresis. J Pharm Pharmacol 2011; 13:504-6. [PMID: 13686904 DOI: 10.1111/j.2042-7158.1961.tb11859.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Abstract
A method for the quantitative separation and estimation of strychnine and brucine in nux vomica seeds has been described. The method involves extraction of total alkaloids, electrophoretic separation in a buffer medium and subsequent estimation in spectrophotometer after elution in suitable solvent. The method is precise and accurate
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Chen M, Chen J, Hou T, Fang Y, Sun W, Hu R, Cai B. [Effect of phospholipid composition on pharmaceutical properties and anti-tumor activity of stealth liposomes containing brucine]. Zhongguo Zhong Yao Za Zhi 2011; 36:864-867. [PMID: 21761723] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
OBJECTIVE To compare the pharmaceutical properties and the anti-tumor activities of three kinds of stealth liposomes prepared with different phospholipid composition containing brucine. METHOD Stealth liposomes with different phospholipids composition, such as soybean phosphatidycholine (SPC), hydrogenated soybean phosphatidylcholine (HSPC) and the complex of SPC and HSPC, were prepared by ammonium sulfate transmembrane gradient method. Pharmaceutical properties such as shape, encapsulation efficiency and size of three stealth liposomes were compared intensively. Anti-tumor activity of SPC, HSPC and novel stealth liposomes composed of both SPC and HSPC were compared by established mouse liver cancer H22 model. Meanwhile, the mice body weight and immune organ weight were also compared. RESULT The encapsulation efficiency of novel, SPC and HSPC stealth liposomes were 77.7%, 64.8% and 74.8%, respectively. The mean diameters of them were less than 100 nm. The tumor inhibition rate of novel, HSPC and SPC stealth liposomes were 57.88%, 49.15%, 23.37%, respectively. The mice body weight, thymus gland index of three stealth liposomes group and spleen index of novel stealth liposomes group had no significant difference with the negative group while SPC and HSPC stealth liposomes group increased the spleen index. CONCLUSION Phospholipids composition is the key factor which determines the antitumor activity of brucine-loaded stealth liposomes.
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Affiliation(s)
- Minglei Chen
- College of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210046, China.
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Brams M, Pandya A, Kuzmin D, van Elk R, Krijnen L, Yakel JL, Tsetlin V, Smit AB, Ulens C. A structural and mutagenic blueprint for molecular recognition of strychnine and d-tubocurarine by different cys-loop receptors. PLoS Biol 2011; 9:e1001034. [PMID: 21468359 PMCID: PMC3066128 DOI: 10.1371/journal.pbio.1001034] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2010] [Accepted: 02/09/2011] [Indexed: 11/18/2022] Open
Abstract
Cys-loop receptors (CLR) are pentameric ligand-gated ion channels that mediate fast excitatory or inhibitory transmission in the nervous system. Strychnine and d-tubocurarine (d-TC) are neurotoxins that have been highly instrumental in decades of research on glycine receptors (GlyR) and nicotinic acetylcholine receptors (nAChR), respectively. In this study we addressed the question how the molecular recognition of strychnine and d-TC occurs with high affinity and yet low specificity towards diverse CLR family members. X-ray crystal structures of the complexes with AChBP, a well-described structural homolog of the extracellular domain of the nAChRs, revealed that strychnine and d-TC adopt multiple occupancies and different ligand orientations, stabilizing the homopentameric protein in an asymmetric state. This introduces a new level of structural diversity in CLRs. Unlike protein and peptide neurotoxins, strychnine and d-TC form a limited number of contacts in the binding pocket of AChBP, offering an explanation for their low selectivity. Based on the ligand interactions observed in strychnine- and d-TC-AChBP complexes we performed alanine-scanning mutagenesis in the binding pocket of the human α1 GlyR and α7 nAChR and showed the functional relevance of these residues in conferring high potency of strychnine and d-TC, respectively. Our results demonstrate that a limited number of ligand interactions in the binding pocket together with an energetic stabilization of the extracellular domain are key to the poor selective recognition of strychnine and d-TC by CLRs as diverse as the GlyR, nAChR, and 5-HT3R. Ligand-gated ion channels play an important role in fast electrochemical signaling in the brain. Cys-loop receptors are a class of pentameric ligand-gated ion channels that are activated by specific neurotransmitters, including acetylcholine (ACh), serotonin (5-HT), glycine (Gly), and γ-aminobutyric acid (GABA). Each type of cys-loop receptor contains an extracellular domain that specifically recognizes only one of these four neurotransmitters and opens an ion-conducting channel pore upon ligand binding. In this study, we investigated the poor specificity with which two potent neurotoxic inhibitors, namely strychnine and d-tubocurarine, are recognized by different cys-loop receptors. Using X-ray crystallography we solved 3-dimensional structures of strychnine or d-tubocurarine in complex with ACh binding protein (AChBP), a well-recognized structural homolog of the nicotinic ACh receptor. Based on ligand-receptor interactions observed in AChBP structures we designed mutant GlyR and α7 nAChR to identify hot spots in the binding pocket of these receptors that define potent inhibition by strychnine and d-tubocurarine, respectively. Combined, our results offer detailed understanding of the molecular recognition of antagonists that have high affinity but poor specificity for different cys-loop receptors.
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Affiliation(s)
- Marijke Brams
- Laboratory of Structural Neurobiology, KULeuven, Leuven, Belgium
| | - Anshul Pandya
- Laboratory of Neurobiology, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, North Carolina, United States of America
| | - Dmitry Kuzmin
- Department of Molecular Basis of Neurosignaling, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - René van Elk
- Department of Molecular & Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, VU University, Amsterdam, The Netherlands
| | - Liz Krijnen
- Laboratory of Structural Neurobiology, KULeuven, Leuven, Belgium
| | - Jerrel L. Yakel
- Laboratory of Neurobiology, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, North Carolina, United States of America
| | - Victor Tsetlin
- Department of Molecular Basis of Neurosignaling, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - August B. Smit
- Department of Molecular & Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, VU University, Amsterdam, The Netherlands
| | - Chris Ulens
- Laboratory of Structural Neurobiology, KULeuven, Leuven, Belgium
- * E-mail:
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Boros S, Kövér KE. Low-power composite CPMG HSQMBC experiment for accurate measurement of long-range heteronuclear coupling constants. Magn Reson Chem 2011; 49:106-110. [PMID: 21246626 DOI: 10.1002/mrc.2717] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2010] [Revised: 11/29/2010] [Accepted: 11/30/2010] [Indexed: 05/30/2023]
Abstract
A modified version of CPMG-HSQMBC pulse scheme is presented for the measurement of long-range heteronuclear coupling constants. The method implements adiabatic inversion and refocusing pulses on the heteronucleus. Low-power composite 180° XY-16 CPMG pulse train is applied on both proton and X nuclei during the evolution of long-range couplings to eliminate phase distortions due to co-evolution of homonuclear proton-proton couplings. The pulse sequence yields pure absorption antiphase multiplets allowing precise and direct measurement of the (n)J(XH) coupling constants regardless from the size of the proton-proton couplings. The applicability of the method is demonstrated using strychnine as a model compound. The selective 1D version of the method is also presented.
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Affiliation(s)
- Sándor Boros
- Chinoin Chemical and Pharmaceutical Works Co. Ltd, Member of sanofi-aventis Group, R&D, Analytical Sciences, Budapest, Hungary.
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Kummerlöwe G, Grage SL, Thiele CM, Kuprov I, Ulrich AS, Luy B. Variable angle NMR spectroscopy and its application to the measurement of residual chemical shift anisotropy. J Magn Reson 2011; 209:19-30. [PMID: 21256060 DOI: 10.1016/j.jmr.2010.11.019] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2010] [Revised: 11/30/2010] [Accepted: 11/30/2010] [Indexed: 05/30/2023]
Abstract
The successful measurement of anisotropic NMR parameters like residual dipolar couplings (RDCs), residual quadrupolar couplings (RQCs), or residual chemical shift anisotropy (RCSA) involves the partial alignment of solute molecules in an alignment medium. To avoid any influence of the change of environment from the isotropic to the anisotropic sample, the measurement of both datasets with a single sample is highly desirable. Here, we introduce the scaling of alignment for mechanically stretched polymer gels by varying the angle of the director of alignment relative to the static magnetic field, which we call variable angle NMR spectroscopy (VA-NMR). The technique is closely related to variable angle sample spinning NMR spectroscopy (VASS-NMR) of liquid crystalline samples, but due to the mechanical fixation of the director of alignment no sample spinning is necessary. Also, in contrast to VASS-NMR, VA-NMR works for the full range of sample inclinations between 0° and 90°. Isotropic spectra are obtained at the magic angle. As a demonstration of the approach we measure ¹³C-RCSA values for strychnine in a stretched PDMS/CDCl₃ gel and show their usefulness for assignment purposes. In this context special care has been taken with respect to the exact calibration of chemical shift data, for which three approaches have been derived and tested.
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Affiliation(s)
- Grit Kummerlöwe
- Department Chemie, Lehrstuhl Organische Chemie II, Technische Universität München, Lichtenbergstrasse 4, D-85747 Garching, Germany
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Gil S, Espinosa JF, Parella T. IPAP-HSQMBC: measurement of long-range heteronuclear coupling constants from spin-state selective multiplets. J Magn Reson 2010; 207:312-321. [PMID: 20952232 DOI: 10.1016/j.jmr.2010.09.017] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2010] [Revised: 09/24/2010] [Accepted: 09/24/2010] [Indexed: 05/30/2023]
Abstract
A new NMR approach is proposed for the measurement of long-range heteronuclear coupling constants ((n)J(XH), n>1) in natural abundance molecules. Two complementary in-phase (IP) and anti-phase (AP) data are separately recorded from a modified HSQMBC experiment and then added/subtracted to provide spin-state-selective α/β-HSQMBC spectra. The magnitude of (n)J(XH) can be directly determined by simple analysis of the relative displacement between α- and β-cross-peaks. The robustness of this IPAP-HSQMBC experiment is evaluated experimentally and by simulation using a variety of different conditions. Important aspects such as signal intensity dependence and presence of unwanted cross-talk effects are discussed and examples on the measurement of small proton-carbon ((n)J(CH)) and proton-nitrogen ((n)J(NH)) coupling constants are provided.
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Affiliation(s)
- Sergi Gil
- Servei de Ressonància Magnètica Nuclear, Universitat Autònoma de Barcelona, E-08193-Bellaterra, Barcelona, Spain
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41
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Abstract
Practical experimental performance limits for an ensemble of heteronuclear 2D NMR experiments using a state-of-the-art 600 MHz 1.7 mm Bruker TCI Micro CryoProbe are reported. In the specific case of multiplicity-edited GHSQC, it was possible to acquire data on a 540 ng sample of strychnine (1; ∼1.6 nmol), prepared by serial dilution, which was used as a model compound. The experiments discussed also included GCOSY, (13)C reference spectra, (1)H-(13)C GHMBC, IDR-GHSQC-TOCSY, 1,1-ADEQUATE, and (1)H-(15)N GHMBC.
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Affiliation(s)
- Bruce D Hilton
- Discovery and Preclinical Sciences, Process Chemistry Rapid Structure Characterization Laboratory, Merck Research Laboratories, Summit, New Jersey 07901, USA
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Prasad LG, Krishnakumar V, Jothi M, Nagalakshmi R. Spectroscopic and physicochemical studies on organic crystal of brucine hydrogen maleate pentahydrate. Spectrochim Acta A Mol Biomol Spectrosc 2010; 77:87-91. [PMID: 20573541 DOI: 10.1016/j.saa.2010.04.030] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2009] [Revised: 04/22/2010] [Accepted: 04/28/2010] [Indexed: 05/29/2023]
Abstract
Salt of brucine hydrogen maleate pentahydrate was synthesized and grown as a single crystal by slow evaporation solution growth technique. The cell parameters of the grown crystal were calculated from powder XRD. The presence of the functional groups and the nature of the vibrations were identified in vibrational studies. The decomposition character of the title material was studied by recording TGA/DTA. The way of promotion of electron from ground state to higher energy state was premeditated by recording UV-VIS-NIR spectrum also the mechanical behaviour was deliberated in hardness measurement.
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Affiliation(s)
- L Guru Prasad
- Department of Physics, Periyar University, Salem 636 011, Tamil Nadu, India
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43
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Chen J, Lin A, Chen Z, Wang W, Zhang T, Cai H, Cai B. Ammonium sulfate gradient loading of brucine into liposomes: effect of phospholipid composition on entrapment efficiency and physicochemical properties in vitro. Drug Dev Ind Pharm 2010; 36:245-53. [PMID: 19678739 DOI: 10.1080/03639040903099736] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
BACKGROUND Brucine, the major active alkaloid constituent extracted from traditional Chinese herbal medicine Nux vomica, had been found to possess remarkable antitumor, analgesic, and anti-inflammatory activities. In this study, we attempted to encapsulate brucine into liposomes to improve its therapeutic effects. The entrapment efficiency (EE) and the stability of liposomes are two key factors associated with the therapeutic effects of liposomal drugs. We developed a novel liposome-based brucine formulation that was composed of soybean phosphatidylcholine (SPC) and hydrogenated soybean phosphatidylcholine (HSPC). METHOD The liposomes with different phospholipid composition were characterized for their EE, vesicle size, drug release profile, and leakage in vitro. RESULTS The molar ratio of HSPC/SPC = 1:9 was determined as the optimum ratio. Compared with conventional liposomes composed of only SPC or HSPC, EE of the brucine-loaded novel liposomes was increased markedly, especially at high drug/lipid molar ratios. The results of drug release showed that the novel liposomes were more stable than the conventional SPC liposomes in the presence of fetal calf serum. In addition, the results of the leakage experiments revealed that the novel liposomes also had better stability in phosphate buffer solution (PBS) with respect to drug retention. Although the conventional HSPC liposomes is more stable than the novel liposomes, the novel liposomes composed of 10% HSPC and 90% SPC may still have promising application potential because HSPC is much more expensive than SPC. CONCLUSION Taken together, efficient encapsulation of brucine into the novel liposomes, their improved stability, and the price of phospholipids indicate that the novel liposomes may act as promising carriers for active alkaloids such as brucine.
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Affiliation(s)
- Jun Chen
- College of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, PR China
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44
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Zhao J, Liu Z, Xu J, Yu Y, Feng N. [Preparation and in vitro evaluation of brucine-loaded polylacticacid nanoparticles]. Zhongguo Zhong Yao Za Zhi 2009; 34:2322-2324. [PMID: 20030079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
OBJECTIVE To prepare and evaluate brucine-loaded polylacticacid nanoparticles (Bru-PLA-NPs). METHOD The Bru-PLA-NPs were prepared by solvent diffusion method. The physical, chemical properties and in vitro release behavior of the prepared Bru-PLA-NPs were evaluated, respectively. RESULT The mean particle size of the prepared Bru-PLA-NPs was 95 nm with polydispersity index of 0.362. The zeta potential was -15.68 mV. The mean loading and entrapment efficiency of Bru were 7% and 37%, respectively. Compared with Bru solution, an obvious sustained release behavior of Bru from Bru-PLA-NPs was observed in the in vitro release experiment. CONCLUSION The Bru-PLA-NPs prepared by solvent diffusion method exhibit small particle size, high Bru-loading efficiency, and obvious sustained release in vitro
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Affiliation(s)
- Jihui Zhao
- Department of Pharmaceutics, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China
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45
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Tetala KKR, Swarts JW, Chen B, Janssen AEM, van Beek TA. A three-phase microfluidic chip for rapid sample clean-up of alkaloids from plant extracts. Lab Chip 2009; 9:2085-92. [PMID: 19568679 DOI: 10.1039/b822106e] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
A three-phase microchip was developed for the rapid and efficient small-scale purification of alkaloids from plant extracts. As part of the development of such a three-phase microchip, first a two-phase microchip with two channels (3.2 cm and 9.3 cm) was used to study the extraction efficiency of strychnine nitrate and strychnine at various flow rates. Strychnine was extracted from a basic aqueous phase to a chloroform phase (extraction) or strychnine was extracted from a chloroform phase into an acidic aqueous phase (back extraction). Subsequently, the "simultaneous extraction and back extraction" of strychnine was carried out in a three-phase microchip. The experimental extraction rate and yield were compared with model data. At a residence time of 25 sec, 79.5% of strychnine was extracted into the acidic aqueous phase using the three-phase microchip. In general, a good correlation was found between experimental results and model data for both two- and three-phase extractions. Finally, the three-phase microchip was employed in the purification of alkaloids (strychnine and brucine) from Strychnos seed extracts.
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Affiliation(s)
- Kishore K R Tetala
- Natural Products Chemistry Group, Laboratory of Organic Chemistry, Wageningen University, 6703 HB Wageningen, The Netherlands
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46
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Chen J, Wang W, Cai BC, Hu W, Wang LJ. [Pharmaceutical characteristics of brucine stealth liposomes]. Zhongguo Zhong Yao Za Zhi 2008; 33:2100-2104. [PMID: 19066050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
OBJECTIVE To prepare brucine stealth liposomes and compare the in vitro characteristics with brucine conventional liposomes. METHOD Brucine stealth liposomes and conventional liposomes were both prepared by ammonium sulfate transmembrane gradients. The encapsulation efficiency, particle size, in vitro release profiles and stability were compared respectively. RESULT The encapsulation efficiency of brucine stealth liposomes and conventional liposomes were (80.7 +/- 0.5)%, and (80.5 +/- 0.3)%, respectively. The mean paricle sizes were 103.5 nm and 169. 4 nm, respectively. Whether rat plasma was added or not, the release rate and degree of brucine stealth liposomes were significantly lower than those of conventional liposomes. Brucine stealth liposomes were more stable than conventional liposomes. CONCLUSION As the antitumor durg delivery system, the in vitro characteristics of brucine stealth liposomes are more satisfactory than the corresponding conventional liposomes.
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Affiliation(s)
- Jun Chen
- College of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210029, China
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47
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Wang W, Chen J, Cai BC, Fang Y. [Influencing factors in preparation of brucine liposomes by ammonium sulfate transmembrane gradients]. Zhong Yao Cai 2008; 31:1410-1412. [PMID: 19180971] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
OBJECTIVE To study the influencing factors in preparation of brucine liposomes by ammonium sulfate transmembrane gradients. METHODS The brucine liposomes were separated by Sephadex G-50, and the influence of various factors on the entrapment efficiencies were investigated. RESULTS The entrapment efficiency was enhanced by increased ammonium sulfate concentration, ethanol volume and PC concentration. CONCLUSION Burcine liposomes prepared by ammonium sulfate transmembrance gradients can get a high entrapment efficiency, the main influencing factors were ammonium sulfate concentration, ethanol volume and PC concentration.
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Affiliation(s)
- Wei Wang
- Nanjing University of Traditional Chinese Medicine, Nanjing 210029, China
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Enthart A, Freudenberger JC, Furrer J, Kessler H, Luy B. The CLIP/CLAP-HSQC: pure absorptive spectra for the measurement of one-bond couplings. J Magn Reson 2008; 192:314-322. [PMID: 18411067 DOI: 10.1016/j.jmr.2008.03.009] [Citation(s) in RCA: 170] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2007] [Revised: 02/28/2008] [Accepted: 03/18/2008] [Indexed: 05/26/2023]
Abstract
Heteronuclear residual dipolar one-bond couplings of organic molecules at natural abundance are most easily measured using t2 coupled HSQC spectra. However, inevitably mismatched transfer delays result in phase distortions due to residual dispersive antiphase coherences in such experiments. In this article, slightly modified t2 coupled HSQC experiments with clean inphase (CLIP) multiplets are introduced which also reduce the intensities of undesired long-range cross peaks. With the corresponding antiphase (CLAP) experiment, situations where alpha and beta components overlap can be resolved for all multiplicities in an IPAP manner. A comparison of the experiments using hard pulses and shaped broadband excitation and inversion pulses on the heteronucleus is given and potential spectral artefacts are discussed in detail.
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Affiliation(s)
- Andreas Enthart
- Munich Center for Integrated Protein Science, Department Chemie, Organische Chemie II, Technische Universität München, Lichtenbergstrasse 4, D-85747 Garching, Germany
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Abstract
The concept of supramolecular chirality has assumed increasing importance in association with the development of supramolecular chemistry over the last two decades. In chiral crystals, 2 1 helical molecular assemblies are frequently observed as key motifs. Helical handedness of the 2 1 assemblies, however, has not been determined from the mathematical or crystallographical viewpoints. In this context, we have proposed two new concepts, three-axial chirality and tilt chirality. On the basis of the concepts, we describe supramolecular chirality and determine the handedness of 2 1 assemblies that are composed of relatively complicated molecules with multiple stereogenic centers such as brucine, bile acids, and cinchona alkaloids as well as those of simple molecules.
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Affiliation(s)
- Ichiro Hisaki
- Department of Material and Life Science, Graduate School of Engineering, Osaka University, Suita, Osaka, Japan.
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50
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Han QB, Li SL, Qiao CF, Song JZ, Cai ZW, Pui-Hay But P, Shaw PC, Xu HX. A simple method to identify the unprocessed Strychnos seeds used in herbal medicinal products. Planta Med 2008; 74:458-463. [PMID: 18484543 DOI: 10.1055/s-2008-1034359] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The seeds of Strychnos nux-vomica are popularly used in the treatment of arthritis. Being extremely toxic, the raw seeds are forbidden and must be processed before clinical use. The quality of crude and processed Strychnos seeds can be controlled by examining the toxic alkaloids using established HPLC methods. But this procedure does not work in the case where the seeds are powdered and mixed with other medicinal materials in proprietary production. In this quality control study on Strychnos seeds, the contents of two major toxic alkaloids (strychnine and brucine) and a major non-alkaloid constituent (loganic acid) in twenty-four samples of Strychnos seeds (nine processed and fifteen unprocessed) were compared using published HPLC-UV methods. The results showed that the better the seeds were processed, the less loganic acid was found. The alkaloids and non-alkaloid components simultaneously decreased in processed seeds. The content ratio between alkaloids and loganic acid was clearly different in well-processed and crude Strychnos seeds. Based on this interesting discovery, a simple chromatographic method was established which allows a simultaneous determination of loganic acid and the alkaloids strychnine and brucine. The relative peak area (RPA) of strychnine-to-loganic acid was revealed to be a reliable key quality control parameter in order to effectively identify the processed seeds. This new method has been successfully applied to detect the insufficiently processed Strychnos material in marketed herbal medicinal products.
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Affiliation(s)
- Quan-Bin Han
- Chinese Medicine Laboratory, Hong Kong Jockey Club Institute of Chinese Medicine, Hong Kong, P. R. China
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