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Yang R, Zhou Z, Jiang H, Kam TS, Chen K, Ma Z. Asymmetric Synthesis of Arboduridine. Angew Chem Int Ed Engl 2024; 63:e202316016. [PMID: 38038685 DOI: 10.1002/anie.202316016] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 11/30/2023] [Accepted: 11/30/2023] [Indexed: 12/02/2023]
Abstract
The first asymmetric total synthesis of the monoterpenoid indole alkaloid arboduridine has been accomplished. The tricyclic A/B/D ring system was constructed by an enantioselective Michael reaction followed by intramolecular nucleophilic addition. Intramolecular α-amination of a ketone forged the piperidine ring, while a Horner-Wadsworth-Emmons (HWE) reaction was used to form the pyrrolidine ring. A reduction cyclization cascade led to formation of the tetrahydrofuran ring.
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Affiliation(s)
- Rui Yang
- Key Lab of Functional Molecular Engineering of Guangdong Province, School of Chemistry & Chemical Engineering, South China University of Technology, Wushan Road-381, Guangzhou, 510641, P. R. China
| | - Zeyu Zhou
- Key Lab of Functional Molecular Engineering of Guangdong Province, School of Chemistry & Chemical Engineering, South China University of Technology, Wushan Road-381, Guangzhou, 510641, P. R. China
| | - Huanfeng Jiang
- Key Lab of Functional Molecular Engineering of Guangdong Province, School of Chemistry & Chemical Engineering, South China University of Technology, Wushan Road-381, Guangzhou, 510641, P. R. China
| | - Toh-Seok Kam
- Department of Chemistry, Faculty of Science, Universiti Malaya, 50603, Kuala Lumpur, Malaysia
| | - Kai Chen
- College of Chemistry and Chemical Engineering, Central South University, Changsha, 410083, P. R. China
| | - Zhiqiang Ma
- Key Lab of Functional Molecular Engineering of Guangdong Province, School of Chemistry & Chemical Engineering, South China University of Technology, Wushan Road-381, Guangzhou, 510641, P. R. China
- State Key Laboratory of Chemical Oncogenomics, Guangdong Provincial Key Laboratory of Chemical Genomics, Peking University Shenzhen Graduate School, Shenzhen, Guangdong, 518055, P.R. China
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Abuzaid H, Abdelrazig S, Ferreira L, Collins HM, Kim DH, Lim KH, Kam TS, Thomas NR, Turyanska L, Bradshaw TD. Correction to "Apoferritin-Encapsulated Jerantinine A for Transferrin Receptor Targeting and Enhanced Selectivity in Breast Cancer Therapy". ACS Omega 2024; 9:2012. [PMID: 38222495 PMCID: PMC10785055 DOI: 10.1021/acsomega.3c09291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Indexed: 01/16/2024]
Abstract
[This corrects the article DOI: 10.1021/acsomega.2c00997.].
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Affiliation(s)
- Haneen Abuzaid
- School
of Pharmacy, Biodiscovery Institute, The
University of Nottingham, University Park, Nottingham NG7 2RD, U.K.
| | - Salah Abdelrazig
- School
of Pharmacy, Biodiscovery Institute, The
University of Nottingham, University Park, Nottingham NG7 2RD, U.K.
| | - Lenny Ferreira
- School of
Chemistry, Biodiscovery Institute, The University
of Nottingham, University Park, Nottingham NG7 2RD, U.K.
| | - Hilary M. Collins
- School
of Pharmacy, Biodiscovery Institute, The
University of Nottingham, University Park, Nottingham NG7 2RD, U.K.
| | - Dong-Hyun Kim
- School
of Pharmacy, Biodiscovery Institute, The
University of Nottingham, University Park, Nottingham NG7 2RD, U.K.
| | - Kuan-Hon Lim
- The
University of Nottingham Malaysia, Block B, Malaysia Campus, Jalan Broga, 43500 Semenyih, Selangor, Malaysia
| | - Toh-Seok Kam
- Department
of Chemistry, Faculty of Science, The University
of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Neil R. Thomas
- School of
Chemistry, Biodiscovery Institute, The University
of Nottingham, University Park, Nottingham NG7 2RD, U.K.
| | - Lyudmila Turyanska
- Faculty
of Engineering, The University of Nottingham, Additive Manufacturing Building,
Jubilee Campus, University Park, Nottingham NG7 2RD, U.K.
| | - Tracey D. Bradshaw
- School
of Pharmacy, Biodiscovery Institute, The
University of Nottingham, University Park, Nottingham NG7 2RD, U.K.
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Sim DSY, Tang SY, Low YY, Lim SH, Kam TS. Vobasine, vincamine, voaphylline, tacaman, and iboga alkaloids from Tabernaemontana corymbosa. Phytochemistry 2022; 203:113384. [PMID: 36007666 DOI: 10.1016/j.phytochem.2022.113384] [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] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 08/12/2022] [Accepted: 08/14/2022] [Indexed: 06/15/2023]
Abstract
Thirteen indole alkaloids comprising six vobasine/sarpagine, one vincamine, two voaphylline, two tacaman, one iboga, and one corynantheine alkaloid, were isolated from the leaf extract of Tabernaemontana corymbosa (sample from Taiping, Perak, Malaysia). The structures of these alkaloids were determined based on analysis of the spectroscopic data (NMR and MS), and in the case of vincarudine, the absolute configuration was established by ECD and X-ray diffraction analysis. Vobasidine E represents the first vobasine-type alkaloid characterized by a contracted ring C and loss of the ethylidene/ethyl side chain. A possible biogenetic pathway from a perivine precursor, which was also present in the leaf extract, is presented. Differences in the new alkaloid content between the present and previous sample of the same plant (occurring in a different location) are discussed.
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Affiliation(s)
- Dawn Su-Yin Sim
- Department of Chemistry, Faculty of Science, Universiti Malaya, Kuala Lumpur, 50603, Malaysia
| | - Sin-Yee Tang
- Department of Chemistry, Faculty of Science, Universiti Malaya, Kuala Lumpur, 50603, Malaysia
| | - Yun-Yee Low
- Department of Chemistry, Faculty of Science, Universiti Malaya, Kuala Lumpur, 50603, Malaysia
| | - Siew-Huah Lim
- Department of Chemistry, Faculty of Science, Universiti Malaya, Kuala Lumpur, 50603, Malaysia.
| | - Toh-Seok Kam
- Department of Chemistry, Faculty of Science, Universiti Malaya, Kuala Lumpur, 50603, Malaysia.
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Abuzaid H, Abdelrazig S, Ferreira L, Collins HM, Kim DH, Lim KH, Kam TS, Turyanska L, Bradshaw TD. Apoferritin-Encapsulated Jerantinine A for Transferrin Receptor Targeting and Enhanced Selectivity in Breast Cancer Therapy. ACS Omega 2022; 7:21473-21482. [PMID: 35785302 PMCID: PMC9244903 DOI: 10.1021/acsomega.2c00997] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Accepted: 05/19/2022] [Indexed: 05/03/2023]
Abstract
The O-acetyl (or acetate) derivative of the Aspidosperma alkaloid Jerantinine A (JAa) elicits anti-tumor activity against cancer cell lines including mammary carcinoma cell lines irrespective of receptor status (0.14 < GI50 < 0.38 μM), targeting microtubule dynamics. By exploiting breast cancer cells' upregulated transferrin receptor 1 (TfR1) expression and apoferritin (AFt) recognition, we sought to develop an AFt JAa-delivery vehicle to enhance tumor-targeting and reduce systemic toxicity. Optimizing pH-mediated reassembly, ∼120 JAa molecules were entrapped within AFt. Western blot and flow cytometry demonstrate TfR1 expression in cancer cells. Enhanced internalization of 5-carboxyfluorescein-conjugated human AFt in SKBR3 and MDA-MB-231 cancer cells is observed compared to MRC5 fibroblasts. Accordingly, AFt-JAa delivers significantly greater intracellular JAa levels to SKBR3 and MDA-MB-231 cells than naked JAa (0.2 μM) treatment alone. Compared to naked JAa (0.2 μM), AFt-JAa achieves enhanced growth inhibition (2.5-14-fold; <0.02 μM < GI50 < 0.15 μM) in breast cancer cells; AFt-JAa treatment results in significantly reduced clonal survival, more profound cell cycle perturbation including G2/M arrest, greater reduction in cell numbers, and increased apoptosis compared to the naked agent (p < 0.01). Decreased PLK1 and Mcl-1 expression, together with the appearance of cleaved poly (ADP-ribose)-polymerase, corroborate the augmented potency of AFt-JAa. Hence, we demonstrate that AFt represents a biocompatible vehicle for targeted delivery of JAa, offering potential to minimize toxicity and enhance JAa activity in TfR1-expressing tumors.
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Affiliation(s)
- Haneen Abuzaid
- School
of Pharmacy, Biodiscovery Institute, The
University of Nottingham, University Park, Nottingham NG7 2RD, U.K.
| | - Salah Abdelrazig
- School
of Pharmacy, Biodiscovery Institute, The
University of Nottingham, University Park, Nottingham NG7 2RD, U.K.
| | - Lenny Ferreira
- School
of Pharmacy, Biodiscovery Institute, The
University of Nottingham, University Park, Nottingham NG7 2RD, U.K.
| | - Hilary M. Collins
- School
of Pharmacy, Biodiscovery Institute, The
University of Nottingham, University Park, Nottingham NG7 2RD, U.K.
| | - Dong-Hyun Kim
- School
of Pharmacy, Biodiscovery Institute, The
University of Nottingham, University Park, Nottingham NG7 2RD, U.K.
| | - Kuan-Hon Lim
- The
University of Nottingham Malaysia, Block B, Malaysia Campus, Jalan Broga, 43500 Semenyih, Selangor, Malaysia
| | - Toh-Seok Kam
- Department
of Chemistry, Faculty of Science, The University
of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Lyudmila Turyanska
- Faculty
of Engineering, The University of Nottingham, Additive Manufacturing Building,
Jubilee Campus, University Park, Nottingham NG7 2RD, U.K.
| | - Tracey D. Bradshaw
- School
of Pharmacy, Biodiscovery Institute, The
University of Nottingham, University Park, Nottingham NG7 2RD, U.K.
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Wong SK, Tan YS, Lim SH, Low YY, Kam TS. Arboduridine, a Hexacyclic Caged Monoterpenoid Indole Incorporating Cyclohexane, Piperidine, and Bridged-Fused Pyrrolidine-Tetrahydrofuran Moieties. Tetrahedron Lett 2022. [DOI: 10.1016/j.tetlet.2022.153836] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Wang C, Pang Y, Wu Y, Zhang N, Yang R, Li Y, Chen P, Jiang H, Xu XT, Kam TS, Fan T, Ma Z. Divergent Synthesis of Skeletally Distinct Arboridinine and Arborisidine. Angew Chem Int Ed Engl 2021; 60:26978-26985. [PMID: 34665909 DOI: 10.1002/anie.202110149] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Indexed: 01/10/2023]
Abstract
A divergent synthesis of skeletally distinct arboridinine and arborisidine was achieved. The central divergent strategy was inspired by the divergent biosynthetic cyclization mode of arboridinine and arborisidine and their hidden topological connection. The branch point was reached through a Michael and Mannich cascade process. A site-selective intramolecular Mannich reaction was developed to construct the tetracyclic core of arboridinine, while a site-selective intramolecular α-amination of ketone was used to access the tetracyclic core of arborisidine. A strategic Peterson olefination through intramolecular nucleophile delivery was able to set up the exocyclic olefin of arboridinine.
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Affiliation(s)
- Cheng Wang
- Key Lab of Functional Molecular Engineering of Guangdong Province, School of Chemistry & Chemical Engineering, South China University of Technology, Wushan Road-381, Guangzhou, 510641, China
| | - Yubing Pang
- Key Lab of Functional Molecular Engineering of Guangdong Province, School of Chemistry & Chemical Engineering, South China University of Technology, Wushan Road-381, Guangzhou, 510641, China
| | - Yuecheng Wu
- Key Lab of Functional Molecular Engineering of Guangdong Province, School of Chemistry & Chemical Engineering, South China University of Technology, Wushan Road-381, Guangzhou, 510641, China
| | - Nanping Zhang
- Key Lab of Functional Molecular Engineering of Guangdong Province, School of Chemistry & Chemical Engineering, South China University of Technology, Wushan Road-381, Guangzhou, 510641, China
| | - Rui Yang
- Key Lab of Functional Molecular Engineering of Guangdong Province, School of Chemistry & Chemical Engineering, South China University of Technology, Wushan Road-381, Guangzhou, 510641, China
| | - Ying Li
- School of Biotechnology and Health Sciences, Wuyi University, Jiangmen, 529020, P. R. China
| | - Pengquan Chen
- Key Lab of Functional Molecular Engineering of Guangdong Province, School of Chemistry & Chemical Engineering, South China University of Technology, Wushan Road-381, Guangzhou, 510641, China
| | - Huanfeng Jiang
- Key Lab of Functional Molecular Engineering of Guangdong Province, School of Chemistry & Chemical Engineering, South China University of Technology, Wushan Road-381, Guangzhou, 510641, China
| | - Xue-Tao Xu
- School of Biotechnology and Health Sciences, Wuyi University, Jiangmen, 529020, P. R. China
| | - Toh-Seok Kam
- Department of Chemistry, Faculty of Science, University of Malaya, 50603, Kuala Lumpur, Malaysia
| | - Ting Fan
- Key Lab of Functional Molecular Engineering of Guangdong Province, School of Chemistry & Chemical Engineering, South China University of Technology, Wushan Road-381, Guangzhou, 510641, China
| | - Zhiqiang Ma
- Key Lab of Functional Molecular Engineering of Guangdong Province, School of Chemistry & Chemical Engineering, South China University of Technology, Wushan Road-381, Guangzhou, 510641, China
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Tan CH, Yeap JSY, Lim SH, Low YY, Sim KS, Kam TS. The Bisindole Alkaloids Angustilongines M and A from Alstonia penangiana Induce Mitochondrial Apoptosis and G0/G1 Cell Cycle Arrest in HT-29 Cells through Promotion of Tubulin Polymerization. J Nat Prod 2021; 84:1524-1533. [PMID: 33872002 DOI: 10.1021/acs.jnatprod.1c00013] [Citation(s) in RCA: 3] [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: 06/12/2023]
Abstract
A new linearly fused macroline-sarpagine bisindole, angustilongine M (1), was isolated from the methanolic extract of Alstonia penangiana. The structure of the alkaloid was elucidated based on analysis of the spectroscopic data, and its biological activity was evaluated together with another previously reported macroline-akuammiline bisindole from the same plant, angustilongine A (2). Compounds 1 and 2 showed pronounced in vitro growth inhibitory activity against a wide panel of human cancer cell lines. In particular, the two compounds showed potent and selective antiproliferative activity against HT-29 cells, as well as strong growth inhibitory effects against HT-29 spheroids. Cell death mechanistic studies revealed that the compounds induced mitochondrial apoptosis and G0/G1 cell cycle arrest in HT-29 cells in a time-dependent manner, while in vitro tubulin polymerization assays and molecular docking analysis showed that the compounds are microtubule-stabilizing agents, which are predicted to bind at the β-tubulin subunit at the Taxol-binding site.
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Affiliation(s)
- Chun-Hoe Tan
- Institute of Biological Sciences, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | | | - Siew-Huah Lim
- Department of Chemistry, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Yun-Yee Low
- Department of Chemistry, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Kae-Shin Sim
- Institute of Biological Sciences, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Toh-Seok Kam
- Department of Chemistry, University of Malaya, 50603 Kuala Lumpur, Malaysia
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8
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Abstract
A concise synthesis of the 1,4-diarylbutanoid-phenethylamine alkaloids, schwarzinicines A (1) and B (2), recently isolated from Ficus schwarzii, is reported. Key steps include a Claisen condensation to assemble the 1,4-diaryl-2-butanone intermediate, followed by a reductive amination to furnish the core skeleton of the target compounds. The overall synthetic yields of 1 and 2 were 9.1% and 3.5%, respectively. Synthetic (-)-1, (+)-1 and (±)-1 exhibited comparable vasorelaxation as natural schwarzinicine A on rat isolated aortic rings, suggesting that the observed vasorelaxant effects were not influenced by the chirality at C-2.
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Affiliation(s)
- Fong-Kai Lee
- School of Pharmacy, University of Nottingham Malaysia, Semenyih, Selangor, Malaysia
| | - Premanand Krishnan
- School of Pharmacy, University of Nottingham Malaysia, Semenyih, Selangor, Malaysia
| | - Azira Muhamad
- Malaysia Genome Institute, Kajang, Selangor, Malaysia
| | - Yun-Yee Low
- Department of Chemistry, Faculty of Science, University of Malaya, Kuala Lumpur, Malaysia
| | - Toh-Seok Kam
- Department of Chemistry, Faculty of Science, University of Malaya, Kuala Lumpur, Malaysia
| | - Kang-Nee Ting
- School of Pharmacy, University of Nottingham Malaysia, Semenyih, Selangor, Malaysia
| | - Kuan-Hon Lim
- School of Pharmacy, University of Nottingham Malaysia, Semenyih, Selangor, Malaysia
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Wong SK, Yeap JSY, Tan CH, Sim KS, Lim SH, Low YY, Kam TS. Arbolodinines A−C, biologically-active aspidofractinine-aspidofractinine, aspidofractinine-strychnan, and kopsine-strychnan bisindole alkaloids from Kopsia arborea. Tetrahedron 2021. [DOI: 10.1016/j.tet.2020.131802] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Yeap JSY, Tan CH, Yong KT, Lim KH, Lim SH, Low YY, Kam TS. Macroline, talpinine, and sarpagine alkaloids from Alstonia penangiana. An NMR-based method for differentiating between A. penangiana and A. macrophylla. Phytochemistry 2020; 176:112391. [PMID: 32387883 DOI: 10.1016/j.phytochem.2020.112391] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [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: 01/20/2020] [Revised: 04/13/2020] [Accepted: 04/15/2020] [Indexed: 06/11/2023]
Abstract
Fourteen previously undescribed alkaloids comprising two N-1-hydroxymethylmacroline alkaloids, one talpinine-type oxindole acetal, a pair of equilibrating talpinine-type oxindole hemiacetals, eight oxidized derivatives of sarpagine- and akuammiline-type indole alkaloids, in addition to alstochalotine a diastereomer of gelsochalotine recently isolated from Gelsemium elegans, were isolated from the leaf and stem-bark extracts of Alstonia penangiana. The structures and relative configurations of these alkaloids were established using NMR, MS, and in one instance, confirmed by X-ray diffraction analysis. An NMR-based method is described as a useful chemotaxonomic tool for differentiating between A. penangiana and A. macrophylla. Several of the alkaloids isolated showed appreciable growth inhibitory effects when tested against a number of human cancer cell lines.
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Affiliation(s)
- Joanne Soon-Yee Yeap
- Department of Chemistry, Faculty of Science, University of Malaya, 50603, Kuala Lumpur, Malaysia
| | - Chun-Hoe Tan
- Institute of Biological Sciences, Faculty of Science, University of Malaya, 50603, Kuala Lumpur, Malaysia
| | - Kien-Thai Yong
- Institute of Biological Sciences, Faculty of Science, University of Malaya, 50603, Kuala Lumpur, Malaysia
| | - Kuan-Hon Lim
- School of Pharmacy, University of Nottingham Malaysia Campus, Jalan Broga, 43500, Semenyih, Selangor, Malaysia
| | - Siew-Huah Lim
- Department of Chemistry, Faculty of Science, University of Malaya, 50603, Kuala Lumpur, Malaysia
| | - Yun-Yee Low
- Department of Chemistry, Faculty of Science, University of Malaya, 50603, Kuala Lumpur, Malaysia.
| | - Toh-Seok Kam
- Department of Chemistry, Faculty of Science, University of Malaya, 50603, Kuala Lumpur, Malaysia.
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Alhuthali HM, Bradshaw TD, Lim KH, Kam TS, Seedhouse CH. The natural alkaloid Jerantinine B has activity in acute myeloid leukemia cells through a mechanism involving c-Jun. BMC Cancer 2020; 20:629. [PMID: 32635894 PMCID: PMC7341637 DOI: 10.1186/s12885-020-07119-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Accepted: 06/26/2020] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Acute myeloid leukemia (AML) is a heterogenous hematological malignancy with poor long-term survival. New drugs which improve the outcome of AML patients are urgently required. In this work, the activity and mechanism of action of the cytotoxic indole alkaloid Jerantinine B (JB), was examined in AML cells. METHODS We used a combination of proliferation and apoptosis assays to assess the effect of JB on AML cell lines and patient samples, with BH3 profiling being performed to identify early effects of the drug (4 h). Phosphokinase arrays were adopted to identify potential driver proteins in the cellular response to JB, the results of which were confirmed and extended using western blotting and inhibitor assays and measuring levels of reactive oxygen species. RESULTS AML cell growth was significantly impaired following JB exposure in a dose-dependent manner; potent colony inhibition of primary patient cells was also observed. An apoptotic mode of death was demonstrated using Annexin V and upregulation of apoptotic biomarkers (active caspase 3 and cleaved PARP). Using BH3 profiling, JB was shown to prime cells to apoptosis at an early time point (4 h) and phospho-kinase arrays demonstrated this to be associated with a strong upregulation and activation of both total and phosphorylated c-Jun (S63). The mechanism of c-Jun activation was probed and significant induction of reactive oxygen species (ROS) was demonstrated which resulted in an increase in the DNA damage response marker γH2AX. This was further verified by the loss of JB-induced C-Jun activation and maintenance of cell viability when using the ROS scavenger N-acetyl-L-cysteine (NAC). CONCLUSIONS This work provides the first evidence of cytotoxicity of JB against AML cells and identifies ROS-induced c-Jun activation as the major mechanism of action.
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Affiliation(s)
- Hayaa Moeed Alhuthali
- Blood Cancer and Stem Cells, Division of Cancer and Stem Cells, School of Medicine, Nottingham Biodiscovery Institute, University of Nottingham, Room B209, University Park, Nottingham, NG7 2RD, UK.,College of Applied Medical Science, Taif University, Ta'if, Saudi Arabia
| | | | - Kuan-Hon Lim
- School of Pharmacy, University of Nottingham, Semenyih, Malaysia
| | - Toh-Seok Kam
- Department of Chemistry, University of Malaya, Kuala Lumpur, Malaysia
| | - Claire H Seedhouse
- Blood Cancer and Stem Cells, Division of Cancer and Stem Cells, School of Medicine, Nottingham Biodiscovery Institute, University of Nottingham, Room B209, University Park, Nottingham, NG7 2RD, UK.
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12
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Krishnan P, Lee FK, Yap VA, Low YY, Kam TS, Yong KT, Ting KN, Lim KH. Schwarzinicines A-G, 1,4-Diarylbutanoid-Phenethylamine Conjugates from the Leaves of Ficus schwarzii. J Nat Prod 2020; 83:152-158. [PMID: 31935094 DOI: 10.1021/acs.jnatprod.9b01160] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Schwarzinicines A-G (1-7), representing the first examples of 1,4-diarylbutanoid-phenethylamine conjugates, were isolated from the leaves of Ficus schwarzii. The structures of these compounds were determined by detailed analysis of their MS, 1D and 2D NMR data. Compounds 1-4 exhibited pronounced vasorelaxant effects in the rat isolated aorta (Emax 106-120%; EC50 0.96-2.10 μM). However, compounds 1 and 2 showed no cytotoxic effects against A549, MCF-7, and HCT 116 human cancer cells (IC50 > 10 μM).
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Affiliation(s)
- Premanand Krishnan
- School of Pharmacy , University of Nottingham Malaysia , Jalan Broga , 43500 Semenyih , Selangor , Malaysia
| | - Fong-Kai Lee
- School of Pharmacy , University of Nottingham Malaysia , Jalan Broga , 43500 Semenyih , Selangor , Malaysia
| | - Veronica Alicia Yap
- School of Pharmacy , University of Nottingham Malaysia , Jalan Broga , 43500 Semenyih , Selangor , Malaysia
| | - Yun-Yee Low
- Department of Chemistry, Faculty of Science , University of Malaya , 50603 Kuala Lumpur , Malaysia
| | - Toh-Seok Kam
- Department of Chemistry, Faculty of Science , University of Malaya , 50603 Kuala Lumpur , Malaysia
| | - Kien-Thai Yong
- Institute of Biological Sciences, Faculty of Science , University of Malaya , 50603 Kuala Lumpur , Malaysia
| | - Kang-Nee Ting
- School of Pharmacy , University of Nottingham Malaysia , Jalan Broga , 43500 Semenyih , Selangor , Malaysia
| | - Kuan-Hon Lim
- School of Pharmacy , University of Nottingham Malaysia , Jalan Broga , 43500 Semenyih , Selangor , Malaysia
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13
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Yeap JSY, Saad HM, Tan CH, Sim KS, Lim SH, Low YY, Kam TS. Macroline-Sarpagine Bisindole Alkaloids with Antiproliferative Activity from Alstonia penangiana. J Nat Prod 2019; 82:3121-3132. [PMID: 31642315 DOI: 10.1021/acs.jnatprod.9b00712] [Citation(s) in RCA: 14] [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] [Indexed: 06/10/2023]
Abstract
A methanol extract of the stem bark of the Malayan Alstonia penangiana provided seven new bisindole alkaloids, comprising six macroline-sarpagine alkaloids (angustilongines E-K, 1-6) and one macroline-pleiocarpamine bisindole alkaloid (angustilongine L, 7). Analysis of the spectroscopic data (NMR and MS) of these compounds led to the proposed structures of these alkaloids. The macroline-sarpagine alkaloids (1-6) showed in vitro growth inhibitory activity against a panel of human cancer cell lines, inclusive of KB, vincristine-resistant KB, PC-3, LNCaP, MCF7, MDA-MB-231, HT-29, HCT 116, and A549 cells (IC50 values: 0.02-9.0 μM).
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Affiliation(s)
- Joanne Soon-Yee Yeap
- Department of Chemistry, Faculty of Science , University of Malaya , 50603 Kuala Lumpur , Malaysia
| | - Hazwani Mat Saad
- Institute of Biological Sciences, Faculty of Science , University of Malaya , 50603 Kuala Lumpur , Malaysia
| | - Chun-Hoe Tan
- Institute of Biological Sciences, Faculty of Science , University of Malaya , 50603 Kuala Lumpur , Malaysia
| | - Kae-Shin Sim
- Institute of Biological Sciences, Faculty of Science , University of Malaya , 50603 Kuala Lumpur , Malaysia
| | - Siew-Huah Lim
- Department of Chemistry, Faculty of Science , University of Malaya , 50603 Kuala Lumpur , Malaysia
| | - Yun-Yee Low
- Department of Chemistry, Faculty of Science , University of Malaya , 50603 Kuala Lumpur , Malaysia
| | - Toh-Seok Kam
- Department of Chemistry, Faculty of Science , University of Malaya , 50603 Kuala Lumpur , Malaysia
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Wong SK, Wong SP, Sim KS, Lim SH, Low YY, Kam TS. A Cytotoxic Indole Characterized by Incorporation of a Unique Carbon-Nitrogen Skeleton and Two Pentacyclic Corynanthean Alkaloids Incorporating a Substituted Tetrahydrofuranone Ring from Kopsia arborea. J Nat Prod 2019; 82:1902-1907. [PMID: 31241923 DOI: 10.1021/acs.jnatprod.9b00255] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Three new alkaloids were isolated from the bark extract of the Malayan Kopsia arborea, viz., arbophyllidine (1), an unusual pentacyclic, monoterpenoid indole characterized by an absence of oxygen atoms and incorporating a new carbon-nitrogen skeleton, and arbophyllinines A (2) and B (3), two pentacyclic corynanthean alkaloids incorporating a hydroxyethyl-substituted tetrahydrofuranone ring. The structures of the alkaloids were deduced based on analysis of the MS and NMR data and confirmed by X-ray diffraction analyses. The absolute configuration of arbophyllidine (1) was established based on experimental and calculated ECD data, while that of arbophyllinine A was based on X-ray diffraction analysis (Cu Kα). A reasonable biosynthetic route to arbophyllidine (1) from a pericine precursor is presented. Arbophyllidine (1) showed pronounced in vitro growth inhibitory activity against the HT-29 human cancer cell line with IC50 6.2 μM.
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Affiliation(s)
- Soon-Kit Wong
- Department of Chemistry, Faculty of Science , University of Malaya , 50603 Kuala Lumpur , Malaysia
| | - Suet-Pick Wong
- Department of Chemistry, Faculty of Science , University of Malaya , 50603 Kuala Lumpur , Malaysia
| | - Kae-Shin Sim
- Institute of Biological Sciences, Faculty of Science , University of Malaya , 50603 Kuala Lumpur , Malaysia
| | - Siew-Huah Lim
- Department of Chemistry, Faculty of Science , University of Malaya , 50603 Kuala Lumpur , Malaysia
| | - Yun-Yee Low
- Department of Chemistry, Faculty of Science , University of Malaya , 50603 Kuala Lumpur , Malaysia
| | - Toh-Seok Kam
- Department of Chemistry, Faculty of Science , University of Malaya , 50603 Kuala Lumpur , Malaysia
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15
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Chong KW, Thomas NF, Low YY, Kam TS. Reactions of Anodically Generated Methoxystilbene Cation Radicals: The Influence of Ortho-Substituted Vinyl and Formyl Groups. J Org Chem 2019; 84:7279-7290. [DOI: 10.1021/acs.joc.9b00939] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Kam-Weng Chong
- Department of Chemistry, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Noel F. Thomas
- Department of Chemistry, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Yun-Yee Low
- Department of Chemistry, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Toh-Seok Kam
- Department of Chemistry, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia
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16
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Sim DSY, Navanesan S, Sim KS, Gurusamy S, Lim SH, Low YY, Kam TS. Conolodinines A-D, Aspidosperma- Aspidosperma Bisindole Alkaloids with Antiproliferative Activity from Tabernaemontana corymbosa. J Nat Prod 2019; 82:850-858. [PMID: 30869890 DOI: 10.1021/acs.jnatprod.8b00919] [Citation(s) in RCA: 14] [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] [Indexed: 06/09/2023]
Abstract
Examination of the EtOH extract of the leaves of the Malayan Tabernaemontana corymbosa resulted in the isolation of four new (1-4) and two known bisindole alkaloids (5, 6) of the Aspidosperma- Aspidosperma type. The structures of these alkaloids were determined based on analysis of the spectroscopic data (NMR and HRESIMS). X-ray diffraction analyses of the related bisindole alkaloids conophylline (5) and conophyllinine (6) established the absolute configurations. Treatment of the bisindole alkaloid conophylline (5) with benzeneselenic anhydride gave, in addition to the known bisindole polyervinine (7) previously isolated from another Malayan Tabernaemontana, another bisindole product, 8, an isolable tautomer of 7. X-ray diffraction analyses yielded the absolute configurations of both bisindoles and in addition showed that polyervinine (7) exists primarily as the neutral dione structure. The bisindoles (1-8) and the related conophylline-type bisindoles (9-13) showed pronounced in vitro growth inhibitory activity against an array of human cancer cell lines, including KB, vincristine-resistant KB, PC-3, LNCaP, MCF7, MDA-MB-231, A549, HT-29, and HCT 116 cells, with IC50 values for the active compounds in the 0.01-5 μM range.
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Affiliation(s)
- Dawn Su-Yin Sim
- Department of Chemistry, Faculty of Science , University of Malaya , 50603 Kuala Lumpur , Malaysia
| | - Suerialoasan Navanesan
- Institute of Biological Sciences, Faculty of Science , University of Malaya , 50603 Kuala Lumpur , Malaysia
| | - Kae-Shin Sim
- Institute of Biological Sciences, Faculty of Science , University of Malaya , 50603 Kuala Lumpur , Malaysia
| | - Subramaniam Gurusamy
- School of Chemical and Life Sciences , Nanyang Polytechnic , Singapore 569830 , Singapore
| | - Siew-Huah Lim
- Department of Chemistry, Faculty of Science , University of Malaya , 50603 Kuala Lumpur , Malaysia
| | - Yun-Yee Low
- Department of Chemistry, Faculty of Science , University of Malaya , 50603 Kuala Lumpur , Malaysia
| | - Toh-Seok Kam
- Department of Chemistry, Faculty of Science , University of Malaya , 50603 Kuala Lumpur , Malaysia
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17
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Yeap JSY, Lim KH, Yong KT, Lim SH, Kam TS, Low YY. Lycopodium Alkaloids: Lycoplatyrine A, an Unusual Lycodine-Piperidine Adduct from Lycopodium platyrhizoma and the Absolute Configurations of Lycoplanine D and Lycogladine H. J Nat Prod 2019; 82:324-329. [PMID: 30698428 DOI: 10.1021/acs.jnatprod.8b00754] [Citation(s) in RCA: 7] [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] [Indexed: 06/09/2023]
Abstract
Three new Lycopodium alkaloids comprising two lycodine-type alkaloids (1, 2) and one fawcettimine alkaloid (3), in addition to 16 known alkaloids, were isolated from Lycopodium platyrhizoma. The structures of these alkaloids were elucidated based on analysis of their NMR and MS data. Lycoplatyrine A (1) represents an unusual lycodine-piperidine adduct. The structures and absolute configurations of lycoplanine D (hydroxy-des- N-methyl-α-obscurine, 10) and lycogladine H (11) were confirmed by X-ray diffraction analysis.
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Affiliation(s)
- Joanne Soon-Yee Yeap
- Department of Chemistry, Faculty of Science , University of Malaya , 50603 Kuala Lumpur , Malaysia
| | - Kuan-Hon Lim
- School of Pharmacy , University of Nottingham Malaysia Campus , Jalan Broga , 43500 Semenyih , Selangor , Malaysia
| | - Kien-Thai Yong
- Institute of Biological Sciences, Faculty of Science , University of Malaya , 50603 Kuala Lumpur , Malaysia
| | - Siew-Huah Lim
- Department of Chemistry, Faculty of Science , University of Malaya , 50603 Kuala Lumpur , Malaysia
| | - Toh-Seok Kam
- Department of Chemistry, Faculty of Science , University of Malaya , 50603 Kuala Lumpur , Malaysia
| | - Yun-Yee Low
- Department of Chemistry, Faculty of Science , University of Malaya , 50603 Kuala Lumpur , Malaysia
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18
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Chong KW, Thomas NF, Low YY, Kam TS. Reactivity of Anodically Generated 4-Methoxystilbene Cation Radicals: The Influence of Ortho-Substituted Hydroxymethyl, Aminomethyl, and Carboxylic Acid Groups. J Org Chem 2018; 83:15087-15100. [DOI: 10.1021/acs.joc.8b02360] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Kam-Weng Chong
- Department of Chemistry, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Noel F. Thomas
- Department of Chemistry, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Yun-Yee Low
- Department of Chemistry, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Toh-Seok Kam
- Department of Chemistry, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia
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Smedley CJ, Stanley PA, Qazzaz ME, Prota AE, Olieric N, Collins H, Eastman H, Barrow AS, Lim KH, Kam TS, Smith BJ, Duivenvoorden HM, Parker BS, Bradshaw TD, Steinmetz MO, Moses JE. Sustainable Syntheses of (-)-Jerantinines A & E and Structural Characterisation of the Jerantinine-Tubulin Complex at the Colchicine Binding Site. Sci Rep 2018; 8:10617. [PMID: 30006510 PMCID: PMC6045569 DOI: 10.1038/s41598-018-28880-2] [Citation(s) in RCA: 10] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Accepted: 06/29/2018] [Indexed: 11/13/2022] Open
Abstract
The jerantinine family of Aspidosperma indole alkaloids from Tabernaemontana corymbosa are potent microtubule-targeting agents with broad spectrum anticancer activity. The natural supply of these precious metabolites has been significantly disrupted due to the inclusion of T. corymbosa on the endangered list of threatened species by the International Union for Conservation of Nature. This report describes the asymmetric syntheses of (-)-jerantinines A and E from sustainably sourced (-)-tabersonine, using a straight-forward and robust biomimetic approach. Biological investigations of synthetic (-)-jerantinine A, along with molecular modelling and X-ray crystallography studies of the tubulin-(-)-jerantinine B acetate complex, advocate an anticancer mode of action of the jerantinines operating via microtubule disruption resulting from binding at the colchicine site. This work lays the foundation for accessing useful quantities of enantiomerically pure jerantinine alkaloids for future development.
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Affiliation(s)
- Christopher J Smedley
- La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC 3086, Australia
| | - Paul A Stanley
- School of Pharmacy, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
| | - Mohannad E Qazzaz
- School of Pharmacy, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
| | - Andrea E Prota
- Laboratory of Biomolecular Research, Division of Biology and Chemistry, Paul Scherrer Institute, CH-5232, Villigen PSI, Switzerland
| | - Natacha Olieric
- Laboratory of Biomolecular Research, Division of Biology and Chemistry, Paul Scherrer Institute, CH-5232, Villigen PSI, Switzerland
| | - Hilary Collins
- School of Pharmacy, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
| | - Harry Eastman
- School of Pharmacy, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
| | - Andrew S Barrow
- La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC 3086, Australia
| | - Kuan-Hon Lim
- School of Pharmacy, University of Nottingham Malaysia Campus, Jalan Broga, 43500, Semenyih, Selangor, Malaysia
| | - Toh-Seok Kam
- Department of Chemistry, Faculty of Science, University of Malaya, 50603, Kuala Lumpur, Malaysia
| | - Brian J Smith
- La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC 3086, Australia
| | | | - Belinda S Parker
- La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC 3086, Australia
| | - Tracey D Bradshaw
- School of Pharmacy, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
| | - Michel O Steinmetz
- Laboratory of Biomolecular Research, Division of Biology and Chemistry, Paul Scherrer Institute, CH-5232, Villigen PSI, Switzerland
- University of Basel, Biozentrum, CH-4056, Basel, Switzerland
| | - John E Moses
- La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC 3086, Australia.
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20
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Yeap JSY, Navanesan S, Sim KS, Yong KT, Gurusamy S, Lim SH, Low YY, Kam TS. Ajmaline, Oxindole, and Cytotoxic Macroline-Akuammiline Bisindole Alkaloids from Alstonia penangiana. J Nat Prod 2018; 81:1266-1277. [PMID: 29746134 DOI: 10.1021/acs.jnatprod.8b00170] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [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
Examination of the EtOH extract of the Malayan Alstonia penangiana resulted in the isolation of 10 new alkaloids, comprising two ajmaline (1, 2), four macroline oxindole (3-6), and four macroline-akuammiline bisindole alkaloids (7-10). The structures of these alkaloids were determined based on analysis of the spectroscopic data and, in the case of the oxindole 6 and the bisindole alkaloid 7, also confirmed by X-ray diffraction analysis. The bisindole alkaloids 7 and 8 showed pronounced in vitro growth inhibitory activity against an array of human cancer cell lines, including KB, vincristine-resistant KB, PC-3, LNCaP, MCF7, MDA-MB-231, HT-29, HCT 116, and A549 cells with IC50 values in the 0.3-8.3 μM range.
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Affiliation(s)
| | | | | | | | - Subramaniam Gurusamy
- School of Chemical and Life Sciences , Nanyang Polytechnic , 180 Ang Mo Kio Avenue 8 , Singapore 569830 , Singapore
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Abstract
Reexamination of the absolute configuration of recently isolated eburnane alkaloids from Malaysian Kopsia and Leuconotis species by X-ray diffraction analysis and ECD/TDDFT has revealed the existence of biosynthetic enantiodivergence. Three different scenarios are discerned with respect to the composition of the enantiomeric eburnane alkaloids in these plants: first, where the new eburnane congeners possess the same C-20, C-21 absolute configurations as the common eburnane alkaloids (eburnamonine, eburnamine, isoeburnamine, eburnamenine) occurring in the same plant; second, where the new eburnane congeners possess opposite or enantiomeric C-20, C-21 absolute configurations compared to the common eburnane alkaloids found in the same plant; and, third, where the four common eburnane alkaloids were isolated as racemic or scalemic mixtures, while the new eburnane congeners were isolated as pure enantiomers with a common C-20, C-21 configuration (20α, 21α). Additionally, the same Kopsia species (K. pauciflora) found in two different geographical locations (Peninsular Malaysia and Malaysian Borneo) showed different patterns in the composition of the enantiomeric eburnane alkaloids. Revision of the absolute configurations of a number of new eburnane congeners (previously assigned based on the assumption of a common biogenetic origin to that of the known eburnane alkaloids co-occurring in the same plant) is required based on the present results.
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Affiliation(s)
- Kam-Weng Chong
- Department of Chemistry, Faculty of Science, University of Malaya , 50603 Kuala Lumpur, Malaysia
| | - Joanne Soon-Yee Yeap
- Department of Chemistry, Faculty of Science, University of Malaya , 50603 Kuala Lumpur, Malaysia
| | - Siew-Huah Lim
- Department of Chemistry, Faculty of Science, University of Malaya , 50603 Kuala Lumpur, Malaysia
| | - Jean-Frédéric F Weber
- Atta-ur-Rahman Institute for Natural Product Discovery and Faculty of Pharmacy, Universiti Technologi MARA (UiTM, Selangor Branch), Puncak Alam Campus , 42300 Bandar Puncak Alam, Selangor, Malaysia
| | - Yun-Yee Low
- Department of Chemistry, Faculty of Science, University of Malaya , 50603 Kuala Lumpur, Malaysia
| | - Toh-Seok Kam
- Department of Chemistry, Faculty of Science, University of Malaya , 50603 Kuala Lumpur, Malaysia
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22
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Al-Khdhairawi AAQ, Krishnan P, Mai CW, Chung FFL, Leong CO, Yong KT, Chong KW, Low YY, Kam TS, Lim KH. A Bis-benzopyrroloisoquinoline Alkaloid Incorporating a Cyclobutane Core and a Chlorophenanthroindolizidine Alkaloid with Cytotoxic Activity from Ficus fistulosa var. tengerensis. J Nat Prod 2017; 80:2734-2740. [PMID: 28926237 DOI: 10.1021/acs.jnatprod.7b00500] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Tengerensine (1), isolated as a racemate and constituted from a pair of bis-benzopyrroloisoquinoline enantiomers, and tengechlorenine (2), purified as a scalemic mixture and constituted from a pair of chlorinated phenanthroindolizidine enantiomers, were isolated from the leaves of Ficus fistulosa var. tengerensis, along with three other known alkaloids. The structures of 1 and 2 were determined by spectroscopic data interpretation and X-ray diffraction analysis. The enantiomers of 1 were separated by chiral-phase HPLC, and the absolute configurations of (+)-1 and (-)-1 were established via experimental and calculated ECD data. Compound 1 is notable in being a rare unsymmetrical cyclobutane adduct and is the first example of a dimeric benzopyrroloisoquinoline alkaloid, while compound 2 represents the first naturally occurring halogenated phenanthroindolizidine alkaloid. Compound (+)-1 displayed a selective in vitro cytotoxic effect against MDA-MB-468 cells (IC50 7.4 μM), while compound 2 showed pronounced in vitro cytotoxic activity against all three breast cancer cell lines tested (MDA-MB-468, MDA-MB-231, and MCF7; IC50 values of 0.038-0.91 μM).
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Affiliation(s)
| | - Premanand Krishnan
- School of Pharmacy, University of Nottingham Malaysia Campus , Jalan Broga, 43500 Semenyih, Selangor, Malaysia
| | - Chun-Wai Mai
- School of Pharmacy, International Medical University , Bukit Jalil, 57000 Kuala Lumpur, Malaysia
| | - Felicia Fei-Lei Chung
- Center for Cancer and Stem Cell Research, International Medical University , Bukit Jalil, 57000 Kuala Lumpur, Malaysia
| | - Chee-Onn Leong
- School of Pharmacy, International Medical University , Bukit Jalil, 57000 Kuala Lumpur, Malaysia
- Center for Cancer and Stem Cell Research, International Medical University , Bukit Jalil, 57000 Kuala Lumpur, Malaysia
| | - Kien-Thai Yong
- Institute of Biological Sciences, Faculty of Science, University of Malaya , 50603 Kuala Lumpur, Malaysia
| | - Kam-Weng Chong
- Department of Chemistry, Faculty of Science, University of Malaya , 50603 Kuala Lumpur, Malaysia
| | - Yun-Yee Low
- Department of Chemistry, Faculty of Science, University of Malaya , 50603 Kuala Lumpur, Malaysia
| | - Toh-Seok Kam
- Department of Chemistry, Faculty of Science, University of Malaya , 50603 Kuala Lumpur, Malaysia
| | - Kuan-Hon Lim
- School of Pharmacy, University of Nottingham Malaysia Campus , Jalan Broga, 43500 Semenyih, Selangor, Malaysia
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Abubakar IB, Lim KH, Kam TS, Loh HS. Enhancement of apoptotic activities on brain cancer cells via the combination of γ-tocotrienol and jerantinine A. Phytomedicine 2017; 30:74-84. [PMID: 28545672 DOI: 10.1016/j.phymed.2017.03.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [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: 10/29/2016] [Revised: 02/27/2017] [Accepted: 03/09/2017] [Indexed: 05/14/2023]
Abstract
BACKGROUND γ-Tocotrienol, a vitamin E isomer possesses pronounced in vitro anticancer activities. However, the in vivo potency has been limited by hardly achievable therapeutic levels owing to inefficient high-dose oral delivery which leads to subsequent metabolic degradation. Jerantinine A, an Aspidosperma alkaloid, originally isolated from Tabernaemontana corymbosa, has proved to possess interesting anticancer activities. However, jerantinine A also induces toxicity to non-cancerous cells. PURPOSE We adopted a combinatorial approach with the joint application of γ-tocotrienol and jerantinine A at lower concentrations in order to minimize toxicity towards non-cancerous cells while improving the potency on brain cancer cells. METHODS The antiproliferative potency of individual γ-tocotrienol and jerantinine A as well as combined in low-concentration was firstly evaluated on U87MG cancer and MRC5 normal cells. Morphological changes, DNA damage patterns, cell cycle arrests and the effects of individual and combined low-concentration compounds on microtubules were then investigated. Finally, the potential roles of caspase enzymes and apoptosis-related proteins in mediating the apoptotic mechanisms were investigated using apoptosis antibody array, ELISA and Western blotting analysis. RESULTS Combinatorial study between γ-tocotrienol at a concentration range (0-24µg/ml) and fixed IC20 concentration of jerantinine A (0.16µg/ml) induced a potent antiproliferative effect on U87MG cells and led to a reduction on the new half maximal inhibitory concentration of γ-tocotrienol (i.e.tIC50=1.29µg/ml) as compared to that of individual γ-tocotrienol (i.e. IC50=3.17µg/ml). A reduction on undesirable toxicity to MRC5 normal cells was also observed. G0/G1 cell cycle arrest was evident on U87MG cells receiving IC50 of individual γ-tocotrienol and combined low-concentration compounds (1.29µg/ml γ-tocotrienol + 0.16µg/ml jerantinine A), whereas, a profound G2/M arrest was evident on cells treated with IC50 of individual jerantinine A. Additionally, individual jerantinine A and combined compounds (except individual γ-tocotrienol) caused a disruption of microtubule networks triggering Fas- and p53-induced apoptosis mediated via the death receptor and mitochondrial pathways. CONCLUSIONS These findings demonstrated that the combined use of lower concentrations of γ-tocotrienol and jerantinine A induced potent cytotoxic effects on U87MG cancer cells resulting in a reduction on the required individual concentrations and thereby minimizing toxicity of jerantinine A towards non-cancerous MRC5 cells as well as probably overcoming the high-dose limiting application of γ-tocotrienol. The multi-targeted mechanisms of action of the combination approach have shown a therapeutic potential against brain cancer in vitro and therefore, further in vivo investigations using a suitable animal model should be the way forward.
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Affiliation(s)
- Ibrahim Babangida Abubakar
- School of Biosciences, Faculty of Science, The University of Nottingham Malaysia Campus, Jalan Broga, 43500 Semenyih, Selangor, Malaysia; Department of Biochemistry, Faculty of Science, Kebbi State University of Science and Technology Aleiro, PMB 1144, Kebbi State, Nigeria.
| | - Kuan-Hon Lim
- School of Pharmacy, Faculty of Science, The University of Nottingham Malaysia Campus, Jalan Broga, 43500 Semenyih, Selangor, Malaysia.
| | - Toh-Seok Kam
- Department of Chemistry, University of Malaya, 50603 Kuala Lumpur, Malaysia.
| | - Hwei-San Loh
- School of Biosciences, Faculty of Science, The University of Nottingham Malaysia Campus, Jalan Broga, 43500 Semenyih, Selangor, Malaysia; Biotechnology Research Centre, The University of Nottingham Malaysia Campus, Jalan Broga, 43500 Semenyih, Selangor, Malaysia.
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24
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Chong KW, Hong FJ, Thomas NF, Low YY, Kam TS. Electrochemically Mediated Oxidative Transformations of Substituted 4-Methoxystilbenes: Effect of Ortho-Substituted Nucleophilic Groups. J Org Chem 2017; 82:6172-6191. [PMID: 28552001 DOI: 10.1021/acs.joc.7b00753] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
A systematic study was undertaken to determine the influence of ortho'-substituted nucleophilic groups (OH, NH2, or NHR) on the reactivity of anodically generated 4-methoxy- and 3,4-dimethoxystilbene cation radicals. The results showed that when ortho-substituted nucleophilic groups such as OH and NHR are present in the other ring, both direct and crossover intramolecular cation-nucleophile reactions occur to give bisbenzofurans/bisindoles or fused bisbenzopyrans/bisquinolines, respectively. Where an additional 3-methoxy substituent is present, bridged oxocine/azocine products are formed in addition to the bisbenzopyrans/bisquinolines and bisbenzofurans/bisindoles. Mechanistic rationalization of the observed behavior is presented based on a generalized pathway involving fast cation radical dimerization following electron transfer, followed by direct and crossover trapping of the benzylic cations by the ortho-substituted oxygen and nitrogen nucleophilic groups. In the instances where an additional 3-methoxy group is present, the bridged oxocine/azocine products are also formed as a result of competing aromatic substitution (Friedel-Crafts reaction). The results have shed further light and provided additional clarification on the reactivity of anodically generated stilbene cation radicals.
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Affiliation(s)
- Kam-Weng Chong
- Department of Chemistry, Faculty of Science, University of Malaya , 50603 Kuala Lumpur, Malaysia
| | - Fong-Jiao Hong
- Department of Chemistry, Faculty of Science, University of Malaya , 50603 Kuala Lumpur, Malaysia
| | - Noel F Thomas
- Department of Chemistry, Faculty of Science, University of Malaya , 50603 Kuala Lumpur, Malaysia
| | - Yun-Yee Low
- Department of Chemistry, Faculty of Science, University of Malaya , 50603 Kuala Lumpur, Malaysia
| | - Toh-Seok Kam
- Department of Chemistry, Faculty of Science, University of Malaya , 50603 Kuala Lumpur, Malaysia
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25
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Chung FFL, Tan PFTM, Raja VJ, Tan BS, Lim KH, Kam TS, Hii LW, Tan SH, See SJ, Tan YF, Wong LZ, Yam WK, Mai CW, Bradshaw TD, Leong CO. Jerantinine A induces tumor-specific cell death through modulation of splicing factor 3b subunit 1 (SF3B1). Sci Rep 2017; 7:42504. [PMID: 28198434 PMCID: PMC5309811 DOI: 10.1038/srep42504] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Accepted: 01/13/2017] [Indexed: 02/08/2023] Open
Abstract
Precursor mRNA (pre-mRNA) splicing is catalyzed by a large ribonucleoprotein complex known as the spliceosome. Numerous studies have indicated that aberrant splicing patterns or mutations in spliceosome components, including the splicing factor 3b subunit 1 (SF3B1), are associated with hallmark cancer phenotypes. This has led to the identification and development of small molecules with spliceosome-modulating activity as potential anticancer agents. Jerantinine A (JA) is a novel indole alkaloid which displays potent anti-proliferative activities against human cancer cell lines by inhibiting tubulin polymerization and inducing G2/M cell cycle arrest. Using a combined pooled-genome wide shRNA library screen and global proteomic profiling, we showed that JA targets the spliceosome by up-regulating SF3B1 and SF3B3 protein in breast cancer cells. Notably, JA induced significant tumor-specific cell death and a significant increase in unspliced pre-mRNAs. In contrast, depletion of endogenous SF3B1 abrogated the apoptotic effects, but not the G2/M cell cycle arrest induced by JA. Further analyses showed that JA stabilizes endogenous SF3B1 protein in breast cancer cells and induced dissociation of the protein from the nucleosome complex. Together, these results demonstrate that JA exerts its antitumor activity by targeting SF3B1 and SF3B3 in addition to its reported targeting of tubulin polymerization.
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Affiliation(s)
- Felicia Fei-Lei Chung
- Center for Cancer and Stem Cell Research, International Medical University, Bukit Jalil, 57000 Kuala Lumpur, Malaysia
| | | | - Vijay Joseph Raja
- Department of Biochemistry, Weill Cornell Medical College, New York, NY 10021, USA
| | - Boon-Shing Tan
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Kuan-Hon Lim
- School of Pharmacy, University of Nottingham Malaysia Campus, Jalan Broga, 43500 Semenyih, Selangor, Malaysia
| | - Toh-Seok Kam
- Department of Chemistry, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Ling-Wei Hii
- Center for Cancer and Stem Cell Research, International Medical University, Bukit Jalil, 57000 Kuala Lumpur, Malaysia
- School of Postgraduate Studies, International Medical University, Bukit Jalil, 57000 Kuala Lumpur, Malaysia
| | - Si Hoey Tan
- Center for Cancer and Stem Cell Research, International Medical University, Bukit Jalil, 57000 Kuala Lumpur, Malaysia
- School of Postgraduate Studies, International Medical University, Bukit Jalil, 57000 Kuala Lumpur, Malaysia
| | - Sze-Jia See
- Center for Cancer and Stem Cell Research, International Medical University, Bukit Jalil, 57000 Kuala Lumpur, Malaysia
| | - Yuen-Fen Tan
- Center for Cancer and Stem Cell Research, International Medical University, Bukit Jalil, 57000 Kuala Lumpur, Malaysia
- School of Postgraduate Studies, International Medical University, Bukit Jalil, 57000 Kuala Lumpur, Malaysia
| | - Li-Zhe Wong
- Center for Cancer and Stem Cell Research, International Medical University, Bukit Jalil, 57000 Kuala Lumpur, Malaysia
- School of Postgraduate Studies, International Medical University, Bukit Jalil, 57000 Kuala Lumpur, Malaysia
| | - Wai Keat Yam
- School of Pharmacy, International Medical University, Bukit Jalil, 57000 Kuala Lumpur, Malaysia
| | - Chun Wai Mai
- School of Pharmacy, International Medical University, Bukit Jalil, 57000 Kuala Lumpur, Malaysia
| | - Tracey D. Bradshaw
- School of Pharmacy, University of Nottingham, University Park, Nottingham NG7 2RD, UK
| | - Chee-Onn Leong
- Center for Cancer and Stem Cell Research, International Medical University, Bukit Jalil, 57000 Kuala Lumpur, Malaysia
- School of Pharmacy, International Medical University, Bukit Jalil, 57000 Kuala Lumpur, Malaysia
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26
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Nge CE, Sim KS, Lim SH, Thomas NF, Low YY, Kam TS. A Hexacyclic, Iboga-Derived Monoterpenoid Indole with a Contracted Tetrahydroazepine C-Ring and Incorporation of an Isoxazolidine Moiety, a Seco-Corynanthean, an Aspidosperma-Aspidosperma Bisindole with Anticancer Properties, and the Absolute Configuration of the Pyridopyrimidine Indole Alkaloid, Vernavosine. J Nat Prod 2016; 79:2709-2717. [PMID: 27759387 DOI: 10.1021/acs.jnatprod.6b00674] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [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
Examination of the EtOH extract of the Malayan Tabernaemontana corymbosa resulted in the isolation of three new alkaloids, viz., cononuridine (1), an unusual hexacyclic, iboga-derived, monoterpenoid indole characterized by contraction of the tetrahydroazepine C-ring and incorporation of an additional isoxazolidine ring, taberisidine (2), a seco-corynanthean alkaloid, and conofolidine (3), an Aspidosperma-Aspidosperma bisindole that showed pronounced in vitro growth inhibitory activity against an array of human cancer cell lines, including KB, vincristine-resistant KB, PC-3, LNCaP, MCF7, MDA-MB-231, HT-29, and HCT 116 cells. The structures and absolute configurations of 1 and 3 and the absolute configuration of the novel pyridopyrimidine indole alkaloid vernavosine (4) were confirmed by X-ray diffraction analysis. A reasonable biosynthesis route to cononuridine starting from an iboga precursor is presented.
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Affiliation(s)
- Choy-Eng Nge
- Department of Chemistry and ‡Institute of Biological Sciences, University of Malaya , 50603 Kuala Lumpur, Malaysia
| | - Kae-Shin Sim
- Department of Chemistry and ‡Institute of Biological Sciences, University of Malaya , 50603 Kuala Lumpur, Malaysia
| | - Siew-Huah Lim
- Department of Chemistry and ‡Institute of Biological Sciences, University of Malaya , 50603 Kuala Lumpur, Malaysia
| | - Noel F Thomas
- Department of Chemistry and ‡Institute of Biological Sciences, University of Malaya , 50603 Kuala Lumpur, Malaysia
| | - Yun-Yee Low
- Department of Chemistry and ‡Institute of Biological Sciences, University of Malaya , 50603 Kuala Lumpur, Malaysia
| | - Toh-Seok Kam
- Department of Chemistry and ‡Institute of Biological Sciences, University of Malaya , 50603 Kuala Lumpur, Malaysia
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27
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Nge CE, Chong KW, Thomas NF, Lim SH, Low YY, Kam TS. Ibogan, Aspidosperman, Vincamine, and Bisindole Alkaloids from a Malayan Tabernaemontana corymbosa: Iboga Alkaloids with C-20α Substitution. J Nat Prod 2016; 79:1388-1399. [PMID: 27077800 DOI: 10.1021/acs.jnatprod.6b00129] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Ten new indole alkaloids (1-10) comprising five ibogan, two aspidosperman, one vincamine, and two bisindole alkaloids, in addition to 32 known alkaloids, were isolated from the stem-bark extract of a Malayan Tabernaemontana corymbosa. The structures of these alkaloids were determined based on analysis of the NMR and MS data and, in five instances (1, 3, 5, 6, 8), confirmed by X-ray diffraction analysis. Two of the iboga alkaloids, conodusines B (2) and C (3), and the iboga-containing bisindole tabernamidine B (10) are notable for the presence of an α-substituted acetyl group at C-20 of the iboga carbon skeleton. The iboga alkaloid (+)-conodusine E (5) had MS and NMR data that were identical to those of (-)-ervatamine I, recently isolated from Ervatamia hainanensis. Establishment of the absolute configuration of (+)-conodusine E (5) was based on analysis of the ECD data, correlation with (-)-heyneanine, and X-ray analysis, which showed that (+)-5 belongs to the same enantiomeric series as exemplified by (-)-coronaridine. The configuration at C-20' of the previously reported Tabernaemontana bisindole alkaloid 19'-oxotabernamine (renamed tabernamidine B) required revision based on the present results. Several of the bisindoles showed pronounced in vitro growth inhibitory activity against drug-sensitive and vincristine-resistant KB cells.
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Affiliation(s)
- Choy-Eng Nge
- Department of Chemistry, Faculty of Science, University of Malaya , 50603 Kuala Lumpur, Malaysia
| | - Kam-Weng Chong
- Department of Chemistry, Faculty of Science, University of Malaya , 50603 Kuala Lumpur, Malaysia
| | - Noel F Thomas
- Department of Chemistry, Faculty of Science, University of Malaya , 50603 Kuala Lumpur, Malaysia
| | - Siew-Huah Lim
- Department of Chemistry, Faculty of Science, University of Malaya , 50603 Kuala Lumpur, Malaysia
| | - Yun-Yee Low
- Department of Chemistry, Faculty of Science, University of Malaya , 50603 Kuala Lumpur, Malaysia
| | - Toh-Seok Kam
- Department of Chemistry, Faculty of Science, University of Malaya , 50603 Kuala Lumpur, Malaysia
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28
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Abubakar IB, Lim KH, Kam TS, Loh HS. Synergistic cytotoxic effects of combined δ-tocotrienol and jerantinine B on human brain and colon cancers. J Ethnopharmacol 2016; 184:107-118. [PMID: 26947901 DOI: 10.1016/j.jep.2016.03.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [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: 10/15/2015] [Revised: 02/29/2016] [Accepted: 03/01/2016] [Indexed: 06/05/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE The genus Tabernaemontana has widespread distribution throughout tropical and subtropical parts of the world, i.e. Africa, Asia and America which has long been used for treatments of different disease conditions including tumours, wounds, syphilis, stomach ache and headache. Some Tabernaemontana species are used for treatment of piles, spleen and abdominal tumours in India. In particular, the leaf of Tabernaemontana corymbosa is used for treatment of tumours in Bangladesh. Parts of the plant or whole plants are used as decoctions, steam bath, powder and ointments. AIM OF STUDY The present study was undertaken to study the mechanism of apoptosis induction in human glioblastoma (U87MG) and colorectal adenocarcinoma (HT-29) cancer cells by a novel indole alkaloid, jerantinine B isolated from T. corymbosa, δ-tocotrienol and the combined low-dose treatments of δ-tocotrienol with IC20 dose of jerantinine B. MATERIALS AND METHODS Cell viability, isobologram and combinational index (CI) analyses were used to determine the pharmacological interaction between combined treatments based on the IC50 values obtained. Fluorescence and histochemical staining techniques as well as comet assay were used for evaluating the morphological changes and DNA damage pattern, respectively. The effects of treatments on microtubules, caspase activity and cell death were determined using immunofluorescence technique, caspase colorimetric and neutral red uptake assays, respectively. RESULTS Jerantinine B, δ-tocotrienol and combined low-dose treatments induced a dose-dependent growth inhibition against U87MG and HT-29 cells selectively with less toxicity acted towards the normal MRC5 cells. Synergistic growth inhibition observed with CI values of 0.85 and 0.77 for U87MG and HT-29 cells, resulting in up to 2-fold and 3.8-fold dose reduction of δ-tocotrienol and jerantinine B, respectively. U87MG and HT-29 cells exhibited morphological features of apoptosis and double stranded DNA breaks. Individual and combined treatments induced caspase 8 and 3 activities and cell death independent of caspase activation on U87MG and HT-29 cells. An increased caspase 9 activity was also evident on U87MG and HT-29 treated with combined treatments and HT-29 cells treated with jerantinine B. Jerantinine B and combined low-dose treatments with δ-tocotrienol undoubtedly disrupted the microtubule networks. CONCLUSION The present study demonstrated the mechanism for cytotoxic potency of δ-tocotrienol and jerantinine B against U87MG and HT-29 cells. Furthermore, combined low-dose treatments induced concurrent synergistic inhibition of cancer cell growth with concomitant dose reduction thus minimizing toxicity to normal cells and improving potency of δ-tocotrienol and jerantinine B.
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Affiliation(s)
- Ibrahim Babangida Abubakar
- School of Biosciences, Faculty of Science, The University of Nottingham Malaysia Campus, Jalan Broga, 43500 Semenyih, Selangor, Malaysia.
| | - Kuan-Hon Lim
- School of Pharmacy, Faculty of Science, The University of Nottingham Malaysia Campus, Jalan Broga, 43500 Semenyih, Selangor, Malaysia.
| | - Toh-Seok Kam
- Department of Chemistry, University of Malaya, Jalan Universiti, 50603 Kuala Lumpur, Malaysia.
| | - Hwei-San Loh
- School of Biosciences, Faculty of Science, The University of Nottingham Malaysia Campus, Jalan Broga, 43500 Semenyih, Selangor, Malaysia; Biotechnology Research Centre, The University of Nottingham Malaysia Campus, Jalan Broga, 43500 Semenyih, Selangor, Malaysia.
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29
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Sim DSY, Teoh WY, Sim KS, Lim SH, Thomas NF, Low YY, Kam TS. Vobatensines A-F, Cytotoxic Iboga-Vobasine Bisindoles from Tabernaemontana corymbosa. J Nat Prod 2016; 79:1048-1055. [PMID: 26918761 DOI: 10.1021/acs.jnatprod.5b01117] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Six new bisindole alkaloids of the iboga-vobasine type, vobatensines A-F (1-6), in addition to four known bisindoles (8-11), were isolated from a stem bark extract of a Malayan Tabernaemontana corymbosa. The structures of these alkaloids were determined based on analysis of the spectroscopic data and in the case of vobatensines A (1), B (2), and 16'-decarbomethoxyvoacamine (8) also confirmed by partial syntheses. Nine of these alkaloids (1-5, 8-11) showed pronounced in vitro growth inhibitory activity against human KB, PC-3, LNCaP, HCT 116, HT-29, MCF7, MDA-MB-231, and A549 cancer cells.
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Affiliation(s)
- Dawn Su-Yin Sim
- Department of Chemistry and ‡Institute of Biological Sciences, University of Malaya , 50603 Kuala Lumpur, Malaysia
| | - Wuen-Yew Teoh
- Department of Chemistry and ‡Institute of Biological Sciences, University of Malaya , 50603 Kuala Lumpur, Malaysia
| | - Kae-Shin Sim
- Department of Chemistry and ‡Institute of Biological Sciences, University of Malaya , 50603 Kuala Lumpur, Malaysia
| | - Siew-Huah Lim
- Department of Chemistry and ‡Institute of Biological Sciences, University of Malaya , 50603 Kuala Lumpur, Malaysia
| | - Noel F Thomas
- Department of Chemistry and ‡Institute of Biological Sciences, University of Malaya , 50603 Kuala Lumpur, Malaysia
| | - Yun-Yee Low
- Department of Chemistry and ‡Institute of Biological Sciences, University of Malaya , 50603 Kuala Lumpur, Malaysia
| | - Toh-Seok Kam
- Department of Chemistry and ‡Institute of Biological Sciences, University of Malaya , 50603 Kuala Lumpur, Malaysia
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30
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Wong SP, Chong KW, Lim KH, Lim SH, Low YY, Kam TS. Arborisidine and Arbornamine, Two Monoterpenoid Indole Alkaloids with New Polycyclic Carbon-Nitrogen Skeletons Derived from a Common Pericine Precursor. Org Lett 2016; 18:1618-21. [PMID: 27033525 DOI: 10.1021/acs.orglett.6b00478] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Two new monoterpene indole alkaloids, characterized by previously unencountered natural product skeletons, viz., arborisidine (1), incorporating indolizidine and cyclohexanone moieties fused to an indole unit, and arbornamine (2), incorporating an unprecedented 6/5/6/5/6 "arbornane" skeleton (distinct from the eburnan or tacaman skeleton), were isolated from a Malayan Kopsia arborea. The structures of the alkaloids were determined based on analysis of the NMR and MS data. Possible biogenetic pathways to these alkaloids from a common pericine precursor (3) are presented.
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Affiliation(s)
- Suet-Pick Wong
- Department of Chemistry, Faculty of Science, University of Malaya , 50603 Kuala Lumpur, Malaysia
| | - Kam-Weng Chong
- Department of Chemistry, Faculty of Science, University of Malaya , 50603 Kuala Lumpur, Malaysia
| | - Kuan-Hon Lim
- School of Pharmacy, University of Nottingham Malaysia Campus , Jalan Broga, 43500 Semenyih, Selangor, Malaysia
| | - Siew-Huah Lim
- Department of Chemistry, Faculty of Science, University of Malaya , 50603 Kuala Lumpur, Malaysia
| | - Yun-Yee Low
- Department of Chemistry, Faculty of Science, University of Malaya , 50603 Kuala Lumpur, Malaysia
| | - Toh-Seok Kam
- Department of Chemistry, Faculty of Science, University of Malaya , 50603 Kuala Lumpur, Malaysia
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31
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Qazzaz ME, Raja VJ, Lim KH, Kam TS, Lee JB, Gershkovich P, Bradshaw TD. In vitro anticancer properties and biological evaluation of novel natural alkaloid jerantinine B. Cancer Lett 2016; 370:185-97. [PMID: 26515390 DOI: 10.1016/j.canlet.2015.10.013] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [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: 07/13/2015] [Revised: 10/08/2015] [Accepted: 10/09/2015] [Indexed: 01/13/2023]
Abstract
Natural products play a pivotal role in medicine especially in the cancer arena. Many drugs that are currently used in cancer chemotherapy originated from or were inspired by nature. Jerantinine B (JB) is one of seven novel Aspidosperma indole alkaloids isolated from the leaf extract of Tabernaemontana corymbosa. Preliminary antiproliferative assays revealed that JB and JB acetate significantly inhibited growth and colony formation, accompanied by time- and dose-dependent apoptosis induction in human cancer cell lines. JB significantly arrested cells at the G2/M cell cycle phase, potently inhibiting tubulin polymerisation. Polo-like kinase 1 (PLK1; an early trigger for the G2/M transition) was also dose-dependently inhibited by JB (IC50 1.5 µM). Furthermore, JB provoked significant increases in reactive oxygen species (ROS). Annexin V+ cell populations, dose-dependent accumulation of cleaved-PARP and caspase 3/7 activation, and reduced Bcl-2 and Mcl-1 expression confirm apoptosis induction. Preclinical in silico biopharmaceutical assessment of JB calculated rapid absorption and bioavailability >70%. Doses of 8-16 mg/kg JB were predicted to maintain unbound plasma concentrations >GI50 values in mice during efficacy studies. These findings advocate continued development of JB as a potential chemotherapeutic agent.
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Affiliation(s)
- Mohannad E Qazzaz
- School of Pharmacy, Centre for Biomolecular Sciences, The University of Nottingham, University Park, Nottingham NG7 2RD, UK
| | - Vijay J Raja
- School of Pharmacy, Centre for Biomolecular Sciences, The University of Nottingham, University Park, Nottingham NG7 2RD, UK
| | - Kuan-Hon Lim
- School of Pharmacy, University of Nottingham Malaysia Campus, Jalan Broga, 43500 Semenyih, Selangor, Malaysia
| | - Toh-Seok Kam
- Department of Chemistry, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Jong Bong Lee
- School of Pharmacy, Centre for Biomolecular Sciences, The University of Nottingham, University Park, Nottingham NG7 2RD, UK
| | - Pavel Gershkovich
- School of Pharmacy, Centre for Biomolecular Sciences, The University of Nottingham, University Park, Nottingham NG7 2RD, UK
| | - Tracey D Bradshaw
- School of Pharmacy, Centre for Biomolecular Sciences, The University of Nottingham, University Park, Nottingham NG7 2RD, UK.
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32
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Yap WS, Gan CY, Sim KS, Lim SH, Low YY, Kam TS. Aspidofractinine and Eburnane Alkaloids from a North Borneo Kopsia. Ring-Contracted, Additional Ring-Fused, and Paucidactine-Type Aspidofractinine Alkaloids from K. pauciflora. J Nat Prod 2016; 79:230-239. [PMID: 26717050 DOI: 10.1021/acs.jnatprod.5b00992] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Eleven new indole alkaloids (1-11) comprising seven aspidofractinine and four eburnane alkaloids, were isolated from the stem-bark extract of Kopsia pauciflora occurring in Malaysian Borneo. The aspidofractinine alkaloids include a ring-contracted, an additional ring-fused, a paucidactine regioisomer, two paucidactine, and one kopsine alkaloid. The structures of several of these alkaloids were also confirmed by X-ray diffraction analyses. The bisindole alkaloids isolated, norpleiomutine and kopsoffinol, showed in vitro growth inhibitory activity against human PC-3, HCT-116, MCF-7, and A549 cells and moderate effects in reversing multidrug-resistance in vincristine-resistant human KB cells.
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Affiliation(s)
| | - Chew-Yan Gan
- University Malaysia of Computer Science and Engineering , Jalan Alamanda 2, Precint 1, 62000 Putrajaya, Malaysia
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33
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Lim JL, Sim KS, Yong KT, Loong BJ, Ting KN, Lim SH, Low YY, Kam TS. Biologically active vallesamine, strychnan, and rhazinilam alkaloids from Alstonia: Pneumatophorine, a nor-secovallesamine with unusual incorporation of a 3-ethylpyridine moiety. Phytochemistry 2015; 117:317-324. [PMID: 26125941 DOI: 10.1016/j.phytochem.2015.06.024] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [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: 01/22/2015] [Revised: 04/22/2015] [Accepted: 06/22/2015] [Indexed: 06/04/2023]
Abstract
Four alkaloids comprising two vallesamine, one strychnan, and one pyranopyridine alkaloid, in addition to 32 other known alkaloids were isolated from two Malayan Alstonia species, Alstonia pneumatophora and Alstonia rostrata. The structures of these alkaloids were determined using NMR and MS analyses, and in one instance, confirmed by X-ray diffraction analysis. The nor-6,7-secovallesamine alkaloid, pneumatophorine, is notable for an unusual incorporation of a 3-ethylpyridine moiety in a monoterpenoid indole. The rhazinilam-type alkaloids (rhazinicine, nor-rhazinicine, rhazinal, and rhazinilam) showed strong cytotoxicity toward human KB, HCT-116, MDA-MB-231, and MRC-5 cells, while pneumatophorine, the uleine alkaloid undulifoline, and the strychnan alkaloids, N4-demethylalstogustine and echitamidine, induced concentration dependent relaxation in phenylephrine-precontracted rat aortic rings.
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Affiliation(s)
- Jun-Lee Lim
- Department of Chemistry, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Kae-Shin Sim
- Institute of Biological Sciences, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Kien-Thai Yong
- Institute of Biological Sciences, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Bi-Juin Loong
- Department of Biomedical Sciences, University of Nottingham Malaysia Campus, Jalan Broga, 43500 Semenyih, Selangor, Malaysia
| | - Kang-Nee Ting
- Department of Biomedical Sciences, University of Nottingham Malaysia Campus, Jalan Broga, 43500 Semenyih, Selangor, Malaysia
| | - Siew-Huah Lim
- Department of Chemistry, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Yun-Yee Low
- Department of Chemistry, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Toh-Seok Kam
- Department of Chemistry, University of Malaya, 50603 Kuala Lumpur, Malaysia.
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34
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Wong SP, Gan CY, Lim KH, Ting KN, Low YY, Kam TS. Arboridinine, a Pentacyclic Indole Alkaloid with a New Cage Carbon-Nitrogen Skeleton Derived from a Pericine Precursor. Org Lett 2015; 17:3628-31. [PMID: 26183592 DOI: 10.1021/acs.orglett.5b01757] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A new monoterpene indole alkaloid characterized by an unprecedented pentacyclic cage skeleton, arboridinine (1), was isolated from a Malaysian Kopsia species. The structure and absolute configuration of the alkaloid were determined based on NMR, MS, and X-ray diffraction analysis. A possible biogenetic pathway from a pericine precursor is presented.
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Affiliation(s)
- Suet-Pick Wong
- †Department of Chemistry, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Chew-Yan Gan
- ‡University Malaysia of Computer Science and Engineering, Jalan Alamanda 2, Precint 1, 62000 Putrajaya, Malaysia
| | | | | | - Yun-Yee Low
- †Department of Chemistry, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Toh-Seok Kam
- †Department of Chemistry, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia
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35
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Hong FJ, Chong KW, Low YY, Thomas NF, Kam TS. Transformations of Ferric Chloride-Generated Stilbene Cation Radicals. The Effect of Aromatic Substitution and a Comparison with Anodic Oxidation. Chem Asian J 2015; 10:2207-20. [PMID: 26097065 DOI: 10.1002/asia.201500488] [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] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Indexed: 11/10/2022]
Abstract
A systematic study on the FeCl3-induced oxidation of 1,2-diarylalkenes was carried out with the focus on the variation of product type as a function of aromatic substitution, as well as to compare the reactivity of stilbene cation radicals generated via Fe(III) oxidation with those generated by anodic oxidation. The aromatic substituents were found to fall into three main categories, namely those that give rise to tetralins and/or dehydrotetralins, those that give products possessing pallidol and ampelopsin F-type carbon skeletons, and last, those that give rise to trimeric products, indanes, and dehydrotetralins/tetralins. The latter are those stilbenes with a para-methoxy substituent in one ring and a para- or meta-EWG (CF3, NO2, Cl, F) in the other, and represent the most prominent departure when compared with the behavior of the same stilbenes under the conditions of anodic oxidation. Reaction pathways to rationalize the formation of the different products are presented.
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Affiliation(s)
- Fong-Jiao Hong
- Department of Chemistry, University of Malaya, 50603, Kuala Lumpur, Malaysia
| | - Kam-Weng Chong
- Department of Chemistry, University of Malaya, 50603, Kuala Lumpur, Malaysia
| | - Yun-Yee Low
- Department of Chemistry, University of Malaya, 50603, Kuala Lumpur, Malaysia
| | - Noel F Thomas
- Department of Chemistry, University of Malaya, 50603, Kuala Lumpur, Malaysia
| | - Toh-Seok Kam
- Department of Chemistry, University of Malaya, 50603, Kuala Lumpur, Malaysia.
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36
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Lim KH, Raja VJ, Bradshaw TD, Lim SH, Low YY, Kam TS. Ibogan, tacaman, and cytotoxic bisindole alkaloids from tabernaemontana. Cononusine, an iboga alkaloid with unusual incorporation of a pyrrolidone moiety. J Nat Prod 2015; 78:1129-1138. [PMID: 25919190 DOI: 10.1021/acs.jnatprod.5b00117] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Six new indole alkaloids, viz., cononusine (1, a rare example of an iboga-pyrrolidone conjugate), ervaluteine (2), vincamajicine (3), tacamonidine (4), 6-oxoibogaine (5), and N(4)-chloromethylnorfluorocurarine chloride (6), and two new vobasinyl-iboga bisindole alkaloids, ervatensines A (7) and B (8), in addition to other known alkaloids, were isolated from the stem-bark extract of the Malayan Tabernaemontana corymbosa. The structures of these alkaloids were established on the basis of NMR and MS analyses and, in one instance (7), confirmed by X-ray diffraction analysis. Vincamajicine (3) showed appreciable activity in reversing multidrug resistance in vincristine-resistant KB cells (IC50 2.62 μM), while ervatensines A (7) and B (8) and two other known bisindoles displayed pronounced in vitro growth inhibitory activity against human KB cells (IC50 < 2 μM). Compounds 7 and 8 also showed good growth inhibitory activity against A549, MCF-7, MDA-468, HCT-116, and HT-29 cells (IC50 0.70-4.19 μM). Cell cycle and annexin V-FITC apoptosis assays indicated that compounds 7 and 8 inhibited proliferation of HCT-116 and MDA-468 cells, evoking apoptotic and necrotic cell death.
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Affiliation(s)
- Kuan-Hon Lim
- †School of Pharmacy, University of Nottingham Malaysia Campus, Jalan Broga, 43500 Semenyih, Selangor, Malaysia
| | - Vijay J Raja
- ‡School of Pharmacy, Centre for Biomolecular Sciences, The University of Nottingham, University Park, Nottingham, Nottinghamshire NG72RD, U.K
| | - Tracey D Bradshaw
- ‡School of Pharmacy, Centre for Biomolecular Sciences, The University of Nottingham, University Park, Nottingham, Nottinghamshire NG72RD, U.K
| | - Siew-Huah Lim
- §Department of Chemistry, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Yun-Yee Low
- §Department of Chemistry, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Toh-Seok Kam
- §Department of Chemistry, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia
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37
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Yap VA, Loong BJ, Ting KN, Loh SHS, Yong KT, Low YY, Kam TS, Lim KH. Hispidacine, an unusual 8,4'-oxyneolignan-alkaloid with vasorelaxant activity, and hispiloscine, an antiproliferative phenanthroindolizidine alkaloid, from Ficus hispida Linn. Phytochemistry 2015; 109:96-102. [PMID: 25468714 DOI: 10.1016/j.phytochem.2014.10.032] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [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: 09/13/2014] [Revised: 10/24/2014] [Accepted: 10/29/2014] [Indexed: 05/24/2023]
Abstract
Hispidacine, an 8,4'-oxyneolignan featuring incorporation of an unusual 2-hydroxyethylamine moiety at C-7, and hispiloscine, a phenanthroindolizidine alkaloid, were isolated from the stem-bark and leaves of the Malaysian Ficus hispida Linn. Their structures were established by spectroscopic analysis. Hispidacine induced a moderate vasorelaxant activity in rat isolated aorta, while hispiloscine showed appreciable antiproliferative activities against MDA-MB-231, MCF-7, A549, HCT-116 and MRC-5 cell lines.
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Affiliation(s)
- Veronica Alicia Yap
- School of Pharmacy, University of Nottingham Malaysia Campus, Jalan Broga, 43500 Semenyih, Selangor, Malaysia
| | - Bi-Juin Loong
- Department of Biomedical Sciences, University of Nottingham Malaysia Campus, Jalan Broga, 43500 Semenyih, Selangor, Malaysia
| | - Kang-Nee Ting
- Department of Biomedical Sciences, University of Nottingham Malaysia Campus, Jalan Broga, 43500 Semenyih, Selangor, Malaysia
| | - Sandy Hwei-San Loh
- School of Biosciences, University of Nottingham Malaysia Campus, Jalan Broga, 43500 Semenyih, Selangor, Malaysia
| | - Kien-Thai Yong
- Institute of Biological Sciences, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Yun-Yee Low
- Department of Chemistry, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Toh-Seok Kam
- Department of Chemistry, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Kuan-Hon Lim
- School of Pharmacy, University of Nottingham Malaysia Campus, Jalan Broga, 43500 Semenyih, Selangor, Malaysia.
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38
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Nge CE, Gan CY, Lim KH, Ting KN, Low YY, Kam TS. Criofolinine and Vernavosine, New Pentacyclic Indole Alkaloids Incorporating Pyrroloazepine and Pyridopyrimidine Moieties Derived from a Common Yohimbine Precursor. Org Lett 2014; 16:6330-3. [DOI: 10.1021/ol503072g] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Choy-Eng Nge
- Department
of Chemistry, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Chew-Yan Gan
- University Malaysia of Computer Science and Engineering, Jalan Alamanda 2, Precint 1, 62000 Putrajaya, Malaysia
| | | | | | - Yun-Yee Low
- Department
of Chemistry, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Toh-Seok Kam
- Department
of Chemistry, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia
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39
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Gan CY, Yoganathan K, Sim KS, Low YY, Lim SH, Kam TS. Corynanthean, eburnan, secoleuconoxine, and pauciflorine alkaloids from Kopsia pauciflora. Phytochemistry 2014; 108:234-242. [PMID: 25442910 DOI: 10.1016/j.phytochem.2014.09.014] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [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: 07/18/2014] [Revised: 08/28/2014] [Accepted: 09/01/2014] [Indexed: 06/04/2023]
Abstract
Eleven indole alkaloids, comprising four corynanthean, two eburnane, one aspidofractinine, one secoleuconoxine, one andranginine, and two pauciflorine type alkaloids were isolated from the stem-bark and leaf extracts of Kopsia pauciflora. Their structures were determined using NMR and MS analyses. The catharinensine type alkaloid kopsirensine B and the secoleuconoxine alkaloid arboloscine A showed moderate to weak activity in reversing MDR in vincristine-resistant KB cells. The alkaloid content was markedly different compared to that of a sample from Malaysian Borneo.
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Affiliation(s)
- Chew-Yan Gan
- University Malaysia of Computer Science and Engineering, Jalan Alamanda 2, Precint 1, 62000 Putrajaya, Malaysia
| | - K Yoganathan
- Bioinformatics Institute (BII), Agency for Science, Technology and Research (A*STAR), 30 Biopolis Street, 07-01 Matrix, Singapore 138671, Singapore
| | - Kae-Shin Sim
- Institute of Biological Sciences, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Yun-Yee Low
- Department of Chemistry, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Siew-Huah Lim
- Department of Chemistry, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Toh-Seok Kam
- Department of Chemistry, University of Malaya, 50603 Kuala Lumpur, Malaysia.
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40
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Sim DSY, Chong KW, Nge CE, Low YY, Sim KS, Kam TS. Cytotoxic vobasine, tacaman, and corynanthe-tryptamine bisindole alkaloids from Tabernaemontana and structure revision of tronoharine. J Nat Prod 2014; 77:2504-2512. [PMID: 25333996 DOI: 10.1021/np500589u] [Citation(s) in RCA: 24] [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] [Indexed: 06/04/2023]
Abstract
Seven new indole alkaloids (1-7) comprising four vobasine, two tacaman, and one corynanthe-tryptamine bisindole alkaloid were isolated from the stem-bark extract of a Malayan Tabernaemontana. Two of the new vobasine alkaloids (1, 3), as well as 16-epivobasine (15) and 16-epivobasenal (17), showed appreciable cytotoxicity toward KB cells (IC50 ca. 5 μg/mL). The structure of the known Tabernaemontana alkaloid tronoharine (8) was revised based on newly acquired NMR data, as well as X-ray diffraction analysis.
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Affiliation(s)
- Dawn Su-Yin Sim
- Department of Chemistry and ‡Institute of Biological Sciences, University of Malaya , 50603 Kuala Lumpur, Malaysia
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41
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Tan SJ, Lim JL, Low YY, Sim KS, Lim SH, Kam TS. Oxidized derivatives of macroline, sarpagine, and pleiocarpamine alkaloids from Alstonia angustifolia. J Nat Prod 2014; 77:2068-2080. [PMID: 25211145 DOI: 10.1021/np500439u] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [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 total of 20 new indole alkaloids comprising mainly oxidized derivatives of macroline- (including alstofonidine, a macroline indole incorporating a butyrolactone ring-F), pleiocarpamine-, and sarpagine-type alkaloids were isolated from the bark and leaf extracts of Alstonia angustifolia. The structures and relative configurations of these alkaloids were determined using NMR and MS analyses and in some instances confirmed by X-ray diffraction analyses. Alkaloids 3, 7, 35, and 41 showed moderate to weak activity, while 21 showed strong activity in reversing multidrug resistance in vincristine-resistant KB cells.
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Affiliation(s)
- Shin-Jowl Tan
- Department of Chemistry and ‡Institute of Biological Sciences, University of Malaya , 50603 Kuala Lumpur, Malaysia
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42
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Abstract
Racemic andransinine (1), an indole alkaloid derivative obtained during isolation of alkaloids from Alstonia angustiloba and Kopsia pauciflora, was found to undergo spontaneous resolution when crystallized in EtOAc, forming racemic conglomerates (an equimolar mechanical mixture of enantiomerically pure individual crystals). X-ray analyses of the enantiomers (obtained from crystals from EtOAc solution and from chiral-phase HPLC) provided the absolute configuration of each enantiomer as (15R,16S,21R)-(+)-andransinine (1a or I+) and (15S,16R,21S)-(-)-andransinine (1b or I-).
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Affiliation(s)
- Yun-Yee Low
- Department of Chemistry, Faculty of Science, University of Malaya , 50603 Kuala Lumpur, Malaysia
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43
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Raja VJ, Lim KH, Leong CO, Kam TS, Bradshaw TD. Novel antitumour indole alkaloid, Jerantinine A, evokes potent G2/M cell cycle arrest targeting microtubules. Invest New Drugs 2014; 32:838-50. [DOI: 10.1007/s10637-014-0126-1] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2014] [Accepted: 06/03/2014] [Indexed: 01/07/2023]
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44
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Hong FJ, Low YY, Chong KW, Thomas NF, Kam TS. Biomimetic oxidative dimerization of anodically generated stilbene radical cations: effect of aromatic substitution on product distribution and reaction pathways. J Org Chem 2014; 79:4528-43. [PMID: 24754525 DOI: 10.1021/jo500559r] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
A systematic study of the electrochemical oxidation of 1,2-diarylalkenes was carried out with the focus on detailed product studies and variation of product type as a function of aromatic substitution. A reinvestigation of the electrochemical oxidation of 4,4'-dimethoxystilbene under various conditions was first carried out, and all products formed were fully characterized and quantitated. This was followed by a systematic investigation of the effect of aromatic substitution on the nature and distribution of the products. The aromatic substituents were found to fall into three main categories, viz., substrates in which the nature and position of the aromatic substituents gave rise to essentially the same products as 4,4'-dimethoxystilbene, for example, tetraaryltetrahydrofurans, dehydrotetralins, and aldehydes (p-MeO or p-NMe2 on one ring and X on the other ring, where X = o-MeO or p-alkyl, or m- or p-EWG; e.g., 4-methoxy-4'-trifluoromethylstilbene); those that gave rise to a mixture of indanyl (or tetralinyl) acetamides and dehydrotetralins (or pallidols) (both or one ring substituted by alkyl groups, e.g., 4,4'-dimethylstilbene); and those where strategic placement of donor groups, such as OMe and OH, led to the formation of ampelopsin F and pallidol-type carbon skeletons (e.g., 4,3',4'-trimethoxystilbene). Reaction pathways to rationalize the formation of the different products are presented.
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Affiliation(s)
- Fong-Jiao Hong
- Department of Chemistry, Faculty of Science, University of Malaya , 50603 Kuala Lumpur, Malaysia
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45
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Low YY, Hong FJ, Lim KH, Thomas NF, Kam TS. Transformations of the 2,7-Seco Aspidosperma alkaloid leuconolam, structure revision of epi-leuconolam, and partial syntheses of leuconoxine and leuconodines A and F. J Nat Prod 2014; 77:327-338. [PMID: 24428198 DOI: 10.1021/np400922x] [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
Several transformations of the seco Aspidosperma alkaloid leuconolam were carried out. The based-induced reaction resulted in cyclization to yield two epimers, the major product corresponding to the optical antipode of a (+)-meloscine derivative. The structures and relative configuration of the products were confirmed by X-ray diffraction analysis. Reaction of leuconolam and epi-leuconolam with various acids, molecular bromine, and hydrogen gave results that indicated that the structure of the alkaloid, previously assigned as epi-leuconolam, was incorrect. This was confirmed by an X-ray diffraction analysis, which revealed that epi-leuconolam is in fact 6,7-dehydroleuconoxine. Short partial syntheses of the diazaspiro indole alkaloid leuconoxine and the new leuconoxine-type alkaloids leuconodines A and F were carried out.
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Affiliation(s)
- Yun-Yee Low
- Department of Chemistry, Faculty of Science, University of Malaya , 50603 Kuala Lumpur, Malaysia
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46
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Lim SH, Low YY, Sinniah SK, Yong KT, Sim KS, Kam TS. Macroline, akuammiline, sarpagine, and ajmaline alkaloids from Alstonia macrophylla. Phytochemistry 2014; 98:204-215. [PMID: 24342109 DOI: 10.1016/j.phytochem.2013.11.014] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [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: 08/07/2013] [Revised: 11/04/2013] [Accepted: 11/21/2013] [Indexed: 06/03/2023]
Abstract
A total of seventeen alkaloids, comprising six macroline (including alstofolinine A, a macroline indole incorporating a butyrolactone ring-E), two ajmaline, one sarpagine, and eight akuammiline alkaloids, were isolated from the stem-bark and leaf extracts of the Malayan Alstonia macrophylla. The structure and relative configurations of these alkaloids were established using NMR, MS and in several instances, confirmed by X-ray diffraction analysis. Six of these alkaloids were effective in reversing multidrug-resistance (MDR) in vincristine-resistant KB cells.
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Affiliation(s)
- Siew-Huah Lim
- Department of Chemistry, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Yun-Yee Low
- Department of Chemistry, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | | | - Kien-Thai Yong
- Institute of Biological Sciences, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Kae-Shin Sim
- Institute of Biological Sciences, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Toh-Seok Kam
- Department of Chemistry, University of Malaya, 50603 Kuala Lumpur, Malaysia.
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47
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Nge CE, Gan CY, Low YY, Thomas NF, Kam TS. Voatinggine and tabertinggine, pentacyclic indole alkaloids derived from an iboga precursor via a common cleavamine-type intermediate. Org Lett 2013; 15:4774-7. [PMID: 23991636 DOI: 10.1021/ol4021404] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Two new indole alkaloids, voatinggine (1) and tabertinggine (2), which are characterized by previously unencountered natural product skeletons, were isolated from a Malayan Tabernaemontana species. The structures and absolute configuration of these alkaloids were determined using NMR and MS analysis, and X-ray diffraction analysis. A possible biogenetic pathway to these novel alkaloids from an iboga precursor, and via a common cleavamine-type intermediate, is presented.
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Affiliation(s)
- Choy-Eng Nge
- Department of Chemistry, Faculty of Science, University of Malaya , 50603 Kuala Lumpur, Malaysia
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48
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Abstract
Eight new indole alkaloids (1-8) belonging to the rhazinilam-leuconolam-leuconoxine group, in addition to 52 other alkaloids, were isolated from the stem-bark extract of Leuconotis griffithii, viz., nor-rhazinicine (1), 5,21-dihydrorhazinilam-N-oxide (2), 3,14-dehydroleuconolam (3), and leuconodines A-E (4-8). The structures of these alkaloids were determined using NMR and MS analyses and in some instances confirmed by X-ray diffraction analyses. Alkaloids 1, 5, and 7 showed only moderate to weak cytotoxicity toward KB cells (IC50 12-18 μg/mL), while 8 showed moderate activity in reversing MDR in vincristine-resistant KB cells.
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Affiliation(s)
- Chew-Yan Gan
- Department of Chemistry, University of Malaya, Kuala Lumpur, Malaysia
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49
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Tan SJ, Lim KH, Subramaniam G, Kam TS. Macroline-sarpagine and macroline-pleiocarpamine bisindole alkaloids from Alstonia angustifolia. Phytochemistry 2013; 85:194-202. [PMID: 22995929 DOI: 10.1016/j.phytochem.2012.08.016] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [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: 06/28/2012] [Accepted: 08/22/2012] [Indexed: 06/01/2023]
Abstract
Nine bisindole alkaloids, comprising four belonging to the macroline-sarpagine group, and five belonging to the macroline-pleiocarpamine group, were isolated from the stem-bark extracts of Alstonia angustifolia (Apocynacea). Their structures were established using NMR and MS analyses.
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Affiliation(s)
- Shin-Jowl Tan
- Department of Chemistry, University of Malaya, 50603 Kuala Lumpur, Malaysia
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50
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Abstract
Odd Couple Methodology for the synthesis of alkaloid-pyrones using a novel pyrone annulation of β–carbolines and indoles with 3-siloxy-4-pyrones is reported. The approach has enabled semisynthesis of the unprecedented alkaloid-pyrone pleiomaltinine from the plant-derived indole-alkaloid pleiocarpamine.
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Affiliation(s)
- Robert E. Ziegler
- Department of Chemistry, Center for Chemical Methodology and Library Development (CMLD-BU), Boston University, 590 Commonwealth Avenue, Boston, MA 02215, USA, Fax: (+1) 617-358-2847
| | - Shin-Jowl Tan
- Department of Chemistry, University of Malaya, Kuala Lumpur, Malaysia 50603
| | - Toh-Seok Kam
- Department of Chemistry, University of Malaya, Kuala Lumpur, Malaysia 50603
| | - John A. Porco
- Department of Chemistry, Center for Chemical Methodology and Library Development (CMLD-BU), Boston University, 590 Commonwealth Avenue, Boston, MA 02215, USA, Fax: (+1) 617-358-2847
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