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Sanz CG, Dias KA, Bacil RP, Serafim RA, Andrade LH, Ferreira EI, Serrano SH. Electrochemical characterization of para- and meta-nitro substituents in aqueous media of new antichagasic pharmaceutical leaders. Electrochim Acta 2021. [DOI: 10.1016/j.electacta.2020.137582] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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2
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99mTc Labelling Strategies for the Development of Potential Nitroimidazolic Hypoxia Imaging Agents. INORGANICS 2019. [DOI: 10.3390/inorganics7110128] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Technetium-99m has a rich coordination chemistry that offers many possibilities in terms of oxidation states and donor atom sets. Modifications in the structure of the technetium complexes could be very useful for fine tuning the physicochemical and biological properties of potential 99mTc radiopharmaceuticals. However, systematic study of the influence of the labelling strategy on the “in vitro” and “in vivo” behaviour is necessary for a rational design of radiopharmaceuticals. Herein we present a review of the influence of the Tc complexes’ molecular structure on the biodistribution and the interaction with the biological target of potential nitroimidazolic hypoxia imaging radiopharmaceuticals presented in the literature from 2010 to the present. Comparison with the gold standard [18F]Fluoromisonidazole (FMISO) is also presented.
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Shen X, Gates KS. Enzyme-Activated Generation of Reactive Oxygen Species from Heterocyclic N-Oxides under Aerobic and Anaerobic Conditions and Its Relevance to Hypoxia-Selective Prodrugs. Chem Res Toxicol 2019; 32:348-361. [PMID: 30817135 DOI: 10.1021/acs.chemrestox.9b00036] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Enzymatic one-electron reduction of heterocyclic N-oxides can lead to the intracellular generation of reactive oxygen species via several different chemical pathways. These reactions may be relevant to hypoxia-selective anticancer drugs, antimicrobial agents, and unwanted toxicity of heterocylic nitrogen compounds.
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Negi B, Kumar D, Kumbukgolla W, Jayaweera S, Ponnan P, Singh R, Agarwal S, Rawat DS. Anti-methicillin resistant Staphylococcus aureus activity, synergism with oxacillin and molecular docking studies of metronidazole-triazole hybrids. Eur J Med Chem 2016; 115:426-37. [DOI: 10.1016/j.ejmech.2016.03.041] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Revised: 02/12/2016] [Accepted: 03/16/2016] [Indexed: 01/09/2023]
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5
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Bussy U, Boisseau R, Thobie-Gautier C, Boujtita M. Electrochemistry-mass spectrometry to study reactive drug metabolites and CYP450 simulations. Trends Analyt Chem 2015. [DOI: 10.1016/j.trac.2015.02.017] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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6
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de Paiva YG, Pinho Júnior W, de Souza AA, Costa CO, Silva FP, Lima-Junior CG, Vasconcellos ML, Goulart MO. Electrochemical and computational studies, in protic medium, of Morita-Baylis-Hillman adducts and correlation with leishmanicidal activity. Electrochim Acta 2014. [DOI: 10.1016/j.electacta.2014.05.066] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Mansour AM. Synthesis, spectroscopic, electrochemical, DFT and SAR studies of nifuroxazide complexes with Pd(II), Pt(II) and Ru(II). Polyhedron 2014. [DOI: 10.1016/j.poly.2014.04.020] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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8
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Bolhuis A, Aldrich-Wright JR. DNA as a target for antimicrobials. Bioorg Chem 2014; 55:51-9. [DOI: 10.1016/j.bioorg.2014.03.009] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2014] [Revised: 03/22/2014] [Accepted: 03/24/2014] [Indexed: 11/28/2022]
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Proteomic analysis of a NAP1 Clostridium difficile clinical isolate resistant to metronidazole. PLoS One 2014; 9:e82622. [PMID: 24400070 PMCID: PMC3882210 DOI: 10.1371/journal.pone.0082622] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2013] [Accepted: 10/26/2013] [Indexed: 01/05/2023] Open
Abstract
BACKGROUND Clostridium difficile is an anaerobic, Gram-positive bacterium that has been implicated as the leading cause of antibiotic-associated diarrhea. Metronidazole is currently the first-line treatment for mild to moderate C. difficile infections. Our laboratory isolated a strain of C. difficile with a stable resistance phenotype to metronidazole. A shotgun proteomics approach was used to compare differences in the proteomes of metronidazole-resistant and -susceptible isolates. METHODOLOGY/PRINCIPAL FINDINGS NAP1 C. difficile strains CD26A54_R (Met-resistant), CD26A54_S (reduced- susceptibility), and VLOO13 (Met-susceptible) were grown to mid-log phase, and spiked with metronidazole at concentrations 2 doubling dilutions below the MIC. Peptides from each sample were labeled with iTRAQ and subjected to 2D-LC-MS/MS analysis. In the absence of metronidazole, higher expression was observed of some proteins in C. difficile strains CD26A54_S and CD26A54_R that may be involved with reduced susceptibility or resistance to metronidazole, including DNA repair proteins, putative nitroreductases, and the ferric uptake regulator (Fur). After treatment with metronidazole, moderate increases were seen in the expression of stress-related proteins in all strains. A moderate increase was also observed in the expression of the DNA repair protein RecA in CD26A54_R. CONCLUSIONS/SIGNIFICANCE This study provided an in-depth proteomic analysis of a stable, metronidazole-resistant C. difficile isolate. The results suggested that a multi-factorial response may be associated with high level metronidazole-resistance in C. difficile, including the possible roles of altered iron metabolism and/or DNA repair.
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Tsutsumi LS, Owusu YB, Hurdle JG, Sun D. Progress in the discovery of treatments for C. difficile infection: A clinical and medicinal chemistry review. Curr Top Med Chem 2014; 14:152-75. [PMID: 24236721 PMCID: PMC3921470 DOI: 10.2174/1568026613666131113154753] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Revised: 09/06/2013] [Accepted: 09/15/2013] [Indexed: 02/07/2023]
Abstract
Clostridium difficile is an anaerobic, Gram-positive pathogen that causes C. difficile infection, which results in significant morbidity and mortality. The incidence of C. difficile infection in developed countries has become increasingly high due to the emergence of newer epidemic strains, a growing elderly population, extensive use of broad spectrum antibiotics, and limited therapies for this diarrheal disease. Because treatment options currently available for C. difficile infection have some drawbacks, including cost, promotion of resistance, and selectivity problems, new agents are urgently needed to address these challenges. This review article focuses on two parts: the first part summarizes current clinical treatment strategies and agents under clinical development for C. difficile infection; the second part reviews newly reported anti-difficile agents that have been evaluated or reevaluated in the last five years and are in the early stages of drug discovery and development. Antibiotics are divided into natural product inspired and synthetic small molecule compounds that may have the potential to be more efficacious than currently approved treatments. This includes potency, selectivity, reduced cytotoxicity, and novel modes of action to prevent resistance.
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Affiliation(s)
| | | | | | - Dianqing Sun
- Department of Pharmaceutical Sciences, The Daniel K. Inouye College of Pharmacy, University of Hawai'i at Hilo, 34 Rainbow Drive, Hilo, HI 96720, USA.
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Roouf Bhat A, Arshad M, Ju Lee E, Pokharel S, Choi I, Athar F. Synthesis, characterization, and anti-amoebic activity of N-(pyrimidin-2-yl)benzenesulfonamide derivatives. Chem Biodivers 2013; 10:2267-77. [PMID: 24327446 DOI: 10.1002/cbdv.201300009] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2013] [Indexed: 11/07/2022]
Abstract
A new series of N-(pyrimidin-2-yl)benzenesulfonamide derivatives, 3a-3i and 4a-4i, was synthesized from pyrimidin-2-amines, 2a-2i, with the aim to explore their effects on in vitro growth of Entamoeba histolytica. The chemical structures of the compounds were elucidated by elemental analysis, FT-IR, (1) H- and (13) C-NMR, and ESI mass-spectral data. In vitro anti-amoebic activity was evaluated against HM1 : IMSS strain of Entamoeba histolytica. The IC50 values were calculated by using the double dilution method. The results were compared with the IC50 value of the standard drug 'metronidazole'. The selected compounds were tested for their cytotoxic activities by cell-viability assay using H9C2 cardiac myoblasts cell line, and the results indicated that all the compounds displayed remarkable >80% viabilities to a concentration of 100 μg/ml.
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Affiliation(s)
- Abdul Roouf Bhat
- School of Biotechnology, Yeungnam University, Gyeongsan 712 - 749, Republic of Korea, (phone: +82-53-810-3024; fax: +82-53-810-4769)
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Andres T, Eckmann L, Smith DK. Voltammetry of nitrobenzene with cysteine and other acids in DMSO. Implications for the biological reactivity of reduced nitroaromatics with thiols. Electrochim Acta 2013. [DOI: 10.1016/j.electacta.2013.01.047] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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13
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Hocquet D, Llanes C, Thouverez M, Kulasekara HD, Bertrand X, Plésiat P, Mazel D, Miller SI. Evidence for induction of integron-based antibiotic resistance by the SOS response in a clinical setting. PLoS Pathog 2012; 8:e1002778. [PMID: 22719259 PMCID: PMC3375312 DOI: 10.1371/journal.ppat.1002778] [Citation(s) in RCA: 89] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2012] [Accepted: 05/14/2012] [Indexed: 01/23/2023] Open
Abstract
Bacterial resistance to β-lactams may rely on acquired β-lactamases encoded by class 1 integron-borne genes. Rearrangement of integron cassette arrays is mediated by the integrase IntI1. It has been previously established that integrase expression can be activated by the SOS response in vitro, leading to speculation that this is an important clinical mechanism of acquiring resistance. Here we report the first in vivo evidence of the impact of SOS response activated by the antibiotic treatment given to a patient and its output in terms of resistance development. We identified a new mechanism of modulation of antibiotic resistance in integrons, based on the insertion of a genetic element, the gcuF1 cassette, upstream of the integron-borne cassette blaOXA-28 encoding an extended spectrum β-lactamase. This insertion creates the fused protein GCUF1-OXA-28 and modulates the transcription, the translation, and the secretion of the β-lactamase in a Pseudomonas aeruginosa isolate (S-Pae) susceptible to the third generation cephalosporin ceftazidime. We found that the metronidazole, not an anti-pseudomonal antibiotic given to the first patient infected with S-Pae, triggered the SOS response that subsequently activated the integrase IntI1 expression. This resulted in the rearrangement of the integron gene cassette array, through excision of the gcuF1 cassette, and the full expression the β-lactamase in an isolate (R-Pae) highly resistant to ceftazidime, which further spread to other patients within our hospital. Our results demonstrate that in human hosts, the antibiotic-induced SOS response in pathogens could play a pivotal role in adaptation process of the bacteria. The bacterial SOS response is a conserved regulatory network that is induced in response to DNA damage. Its activation in vitro leads to the emergence of resistance to antibiotics, leading to speculation that this is an important clinical mechanism of acquiring resistance. We found evidence here that antibiotic-induced SOS response plays a role in bacterial genome rearrangement in vivo within humans. The major classes of antibiotics can trigger the bacterial SOS response and our data raise questions about their wide use and their subsequent effect on the bacterial genetic adaptability. This suggests that emergence of antibiotic resistance during therapy could be reduced by inhibiting the bacterial SOS response. We showed that acquired resistance genes could spread latently in susceptible bacterial strains until needed. These findings could impact current policies for control of antibiotic resistance, which rely on the detection of resistant bacteria and on the assumption that resistance mechanisms have a functional cost to the bacteria. More generally, SOS response may spur changes in the behavior of bacteria and their faster adaptation to hostile environments, including humans.
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Affiliation(s)
- Didier Hocquet
- Department of Immunology, Medicine and Microbiology, University of Washington, Seattle, Washington, United States of America
- EA4266, Laboratoire de Bactériologie, Université de Franche-Comté, Besançon, France
| | - Catherine Llanes
- EA4266, Laboratoire de Bactériologie, Université de Franche-Comté, Besançon, France
| | - Michelle Thouverez
- Laboratoire d'Hygiène Hospitalière, CHRU, Besançon, France
- UMR6249 Chrono-Environnement, Université de Franche-Comté, Besançon, France
| | - Hemantha D. Kulasekara
- Department of Immunology, Medicine and Microbiology, University of Washington, Seattle, Washington, United States of America
| | - Xavier Bertrand
- Laboratoire d'Hygiène Hospitalière, CHRU, Besançon, France
- UMR6249 Chrono-Environnement, Université de Franche-Comté, Besançon, France
| | - Patrick Plésiat
- EA4266, Laboratoire de Bactériologie, Université de Franche-Comté, Besançon, France
| | - Didier Mazel
- Institut Pasteur, Unité Plasticité du Génome Bactérien, CNRS UMR3525, Département Génomes et Génétique, Paris, France
- * E-mail: (DM); (SIM)
| | - Samuel I. Miller
- Department of Immunology, Medicine and Microbiology, University of Washington, Seattle, Washington, United States of America
- * E-mail: (DM); (SIM)
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Dridi B, Fardeau ML, Ollivier B, Raoult D, Drancourt M. The antimicrobial resistance pattern of cultured human methanogens reflects the unique phylogenetic position of archaea. J Antimicrob Chemother 2011; 66:2038-44. [DOI: 10.1093/jac/dkr251] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
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Ikbal M, Yilmaz G, Dogan H, Alp MY, Cebi AH. The evaluation of genotoxic potential of ornidazole, nitroimidazole, in lymphocyte culture of patients with amebiasis. Drug Chem Toxicol 2011; 34:162-6. [PMID: 21314465 DOI: 10.3109/01480545.2010.494668] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The genotoxicity study of ornidazole (ONZ) was carried out on human lymphocyte chromosomes, using sister chromatid exchange (SCE) and micronucleus (MN). Thirty-two patients with Entemoeba histolitica infection who received 1000 mg/day for 10 days were included in this study. SCE and MN were measured before and after therapy. A statistically significant increase was observed in the SCE (P < 0.001) and MN frequencies (P < 0.001) after ornidazole therapy. It was concluded that ONZ has a potential geno- and cytotoxic effect in human peripheral lymphocyte cultures. For this reason, further, detailed studies are needed to elucidate the ONZ mechanism of genotoxicity and its carcinogenic potential.
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Affiliation(s)
- Mevlit Ikbal
- Department of Medical Genetics, Karadeniz Technical University Medical Faculty, Trabzon, Turkey
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Bollo S, Jara-Ulloa P, Zapata-Torres G, Cutiño E, Sturm J, Núñez-Vergara L, Squella J. Voltammetric reduction of 4-nitroimidazole derivatives: Influence of the N-1 substitution in protic and aprotic media. Electrochim Acta 2010. [DOI: 10.1016/j.electacta.2010.03.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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17
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Rivera-Borroto O, Marrero-Ponce Y, Meneses-Marcel A, Escario J, Gómez Barrio A, Arán V, Martins Alho M, Montero Pereira D, Nogal J, Torrens F, Ibarra-Velarde F, Montenegro Y, Huesca-Guillén A, Rivera N, Vogel C. Discovery of Novel Trichomonacidals Using LDA-Driven QSAR Models and Bond-Based Bilinear Indices as Molecular Descriptors. ACTA ACUST UNITED AC 2008. [DOI: 10.1002/qsar.200610165] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Celik A, Aras Ateş N. The Frequency of Sister Chromatid Exchanges in Cultured Human Peripheral Blood Lymphocyte Treated with Metronidazolein Vitro. Drug Chem Toxicol 2008; 29:85-94. [PMID: 16455592 DOI: 10.1080/01480540500408663] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
5-Nitroimidazoles are a group of antiprotozoal and antibacterial agents. Thanks to their antimicrobial activity, these chemotherapeutic agents inhibit the growth of both anaerobic bacteria and certain anaerobic protozoa. One of the useful drugs used in the treatment of infections caused by Trichomonas vaginalis, Entamoeba histolytica, and Giardia lamblia is metronidazole (MTZ). The mutagenicity of metronidazole [1-(hydroxyethyl)-2-methyl-5-nitroimidazole] has been previously shown in different prokaryotic systems but not in eukaryotic systems. The objective of this study is to determine the mutagenic and cytotoxic effects of MTZ at plasma concentration and higher in vitro. In this study, we evaluated the mutagenicity and cytotoxicity of MTZ in cultured human peripheral blood lymphocytes. Doses were selected according to plasma concentration of drug. End points analyzed included mitotic index (MI), replication index (RI), and sister chromatid exchange (SCE). An analysis of variance test (ANOVA) was performed to evaluate the results. A significant decrease (p < 0.001) in MI and RI as well as an increase in SCE frequency (p < 0.001) was observed compared with control cultures. Our results indicate the genotoxic and cytotoxic effect of MTZ in cultured human peripheral blood lymphocytes at plasma concentrations slightly higher than encountered therapeutically.
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Affiliation(s)
- Ayla Celik
- Department of Biology, Faculty of Science and Letters, Mersin University, Mersin, Turkey.
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Marrero-Ponce Y, Meneses-Marcel A, Castillo-Garit JA, Machado-Tugores Y, Escario JA, Barrio AG, Pereira DM, Nogal-Ruiz JJ, Arán VJ, Martínez-Fernández AR, Torrens F, Rotondo R, Ibarra-Velarde F, Alvarado YJ. Predicting antitrichomonal activity: A computational screening using atom-based bilinear indices and experimental proofs. Bioorg Med Chem 2006; 14:6502-24. [PMID: 16875830 DOI: 10.1016/j.bmc.2006.06.016] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2006] [Revised: 06/06/2006] [Accepted: 06/08/2006] [Indexed: 11/30/2022]
Abstract
Existing Trichomonas vaginalis therapies are out of reach for most trichomoniasis people in developing countries and, where available, they are limited by their toxicity (mainly in pregnant women) and their cost. New antitrichomonal agents are needed to combat emerging metronidazole-resistant trichomoniasis and reduce the side effects associated with currently available drugs. Toward this end, atom-based bilinear indices, a new TOMOCOMD-CARDD molecular descriptor, and linear discriminant analysis (LDA) were used to discover novel, potent, and non-toxic lead trichomonacidal chemicals. Two discriminant functions were obtained with the use of non-stochastic and stochastic atom-type bilinear indices for heteroatoms and H-bonding of heteroatoms. These atomic-level molecular descriptors were calculated using a weighting scheme that includes four atomic labels, namely atomic masses, van der Waals volumes, atomic polarizabilities, and atomic electronegativities in Pauling scale. The obtained LDA-based QSAR models, using non-stochastic and stochastic indices, were able to classify correctly 94.51% (90.63%) and 93.41% (93.75%) of the chemicals in training (test) sets, respectively. They showed large Matthews' correlation coefficients (C); 0.89 (0.79) and 0.87 (0.85), for the training (test) sets, correspondingly. The result of predictions on the 15% full-out cross-validation test also evidenced the robustness and predictive power of the obtained models. In addition, canonical regression analyses corroborated the statistical quality of these models (R(can) of 0.749 and of 0.845, correspondingly); they were also used to compute biological activity canonical scores for each compound. On the other hand, a close inspection of the molecular descriptors included in both equations showed that several of these molecular fingerprints are strongly interrelated with each other. Therefore, these models were orthogonalized using the Randić orthogonalization procedure. These classification functions were then applied to find new lead antitrichomonal agents and six compounds were selected as possible active compounds by computational screening. The designed compounds were synthesized and tested for in vitro activity against T. vaginalis. Out of the six compounds that were designed, and synthesized, three molecules (chemicals VA5-5a, VA5-5c, and VA5-12b) showed high to moderate cytocidal activity at the concentration of 10 microg/ml, other two compounds (VA5-8pre and VA5-8) showed high cytocidal and cytostatic activity at the concentration of 100 microg/ml and 10 microg/ml, correspondingly, and the remaining chemical (compound VA5-5e) was inactive at these assayed concentrations. Nonetheless, these compounds possess structural features not seen in known trichomonacidal compounds and thus can serve as excellent leads for further optimization of antitrichomonal activity. The LDA-based QSAR models presented here can be considered as a computer-assisted system that could potentially significantly reduce the number of synthesized and tested compounds and increase the chance of finding new chemical entities with antitrichomonal activity.
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Affiliation(s)
- Yovani Marrero-Ponce
- Institut Universitari de Ciència Molecular, Universitat de València, Edifici d'Instituts de Paterna, Poligon la Coma s/n (detras de Canal Nou), PO Box 22085, E-46071 Valencia, Spain.
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Julião MSDS, Ferreira EI, Ferreira NG, Serrano SH. Voltammetric detection of the interactions between RNO2− and electron acceptors in aqueous medium at highly boron doped diamond electrode (HBDDE). Electrochim Acta 2006. [DOI: 10.1016/j.electacta.2006.03.054] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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21
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S�rgio?da?Silva?Juli�o M, Almeida �, Aquiles?La?Scalea M, Ferreira N, Compton R, Pires?Serrano S. Voltammetric Behavior of Nitrofurazone at Highly Boron Doped Diamond Electrode. ELECTROANAL 2005. [DOI: 10.1002/elan.200403093] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Cavaş T, Ergene-Gözükara S. Genotoxicity evaluation of metronidazole using the piscine micronucleus test by acridine orange fluorescent staining. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2005; 19:107-111. [PMID: 21783466 DOI: 10.1016/j.etap.2004.05.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2004] [Accepted: 05/25/2004] [Indexed: 05/31/2023]
Abstract
In this study, genotoxic potential of metronidazole, an antibiotic-antiparasitic agent widely used both clinical and veterinary areas, was evaluated using the piscine micronucleus test. Specimens of Oreochromis niloticus (Pisces: Cichlidae) were exposed to different concentrations (5, 10, 15mg/L) of metronidazole and 4mg/L cyclophosphamide (as positive control) for 24, 48 and 72h. A fluorescent staining technique with acridine orange (AO) was performed to improve the sensitivity of erythrocyte micronucleus assay with fish. AO selectively stains newly formed immature erythrocytes (PCEs) therefore allows to obtain more sensitive results by detection of the micronucleated PCEs differed than mature erythrocytes (NCEs) by their RNA-containing cytoplasm. The ratio of PCE/NCE in peripheral blood was also evaluated to assess cytotoxicity. As a result, it was observed that the frequencies of micronucleated PCEs increased both dose and time dependently while PCE/NCE ratios decreased. Our results revealed that metronidazole has cytotoxic and genotoxic effects on fish. The use of acridine orange staining technique also seems useful in assessment of short-term genotoxic effects of chemicals, when fish are used as experimental animal.
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Affiliation(s)
- Tolga Cavaş
- Department of Biology, Faculty of Sciences and Letters, Mersin University, 33342 Mersin, Turkey
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Voltammetric studies on nitro radical anion formation from furazolidone and kinetic of the coupled chemical reaction. J Electroanal Chem (Lausanne) 2004. [DOI: 10.1016/j.jelechem.2004.01.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Cavalcanti JCM, de Abreu FC, Oliveira NV, de Moura MABF, Chaves JG, Alves RJ, Bertinaria M, Fruttero R, Goulart MOF. Effect of the leaving group on the electrodic reduction mechanism of anti-Helicobacter pylori metronidazole derivatives, in aprotic and protic media. Bioelectrochemistry 2004; 63:353-7. [PMID: 15110302 DOI: 10.1016/j.bioelechem.2003.10.031] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2003] [Revised: 09/12/2003] [Accepted: 10/06/2003] [Indexed: 12/01/2022]
Abstract
Because redox properties are central to bioreductive drug activity and selectivity, six 2-methyl-5-nitroimidazole, substituted at the N1-ethyl side chain with I, Br, Cl, OAc, OMs and NH(3)(+) were synthesized and submitted to cyclic voltammetry and electrolyses, in order to define their electrodic reduction mechanism, in aprotic [dimethylsulphoxide (DMSO)+0.1 mol l(-1) tetrabuthylammonium perchlorate (TBAP)] and phosphate-buffered media, on glassy carbon electrode, in comparison with metronidazole. Three of these compounds, namely, the iodo, bromo and ammonium salt derivatives showed significant anti-Helicobacter pylori (strain resistant to metronidazole) activity. All the cyclic voltammograms (CV), in aprotic medium, are similar to the one for metronidazole, except for -I, -Br and -NH(3)(+) derivatives. The CV of the N1-ethylhalide (-I, -Br) 5-nitroimidazole showed more intense and irreversible first waves, even at faster sweep rates (nu<2 V s(-1)). The absence of the first wave anodic counterpart, along with analysis of the dependence of E(p), I(p) and other parameters with nu, and results from electrolysis (consumption of two electrons) showed the process to be an ECE system, with halide release, after uptake of two electrons. This behaviour represents a case of dissociative electron transfer (ET). For the ammonium salt, self-protonation mechanism was evident. The facility of reduction represented by the first wave potential and concerning the substituents is NH(3)(+)>Br>I>Cl>OMs>OH>OAc. In aqueous phosphate-buffered medium, the electrochemical behaviour of all the compounds is similar to the one of metronidazole, represented by a unique and irreversible 4e(-)/4H(+) wave. The order of reduction ease is NH(3)(+)>Br approximately OMs>I>OH>OAc. Aprotic medium allows a better discrimination between the substituents. Concerning biological activity, despite the impossibility of establishing a correlation, it has been observed that the more electrophilic compounds showed better anti-H. pylori activity.
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Affiliation(s)
- J C M Cavalcanti
- Departamento de Química, CCEN, UFAL, Cidade Universitária-Tabuleiro do Martins, Maceió, Alagoas 57072-970, Brazil
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25
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Cyclic voltammetric determination of free radical species from nitroimidazopyran: a new antituberculosis agent. J Electroanal Chem (Lausanne) 2004. [DOI: 10.1016/j.jelechem.2003.07.031] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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26
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López Nigro MM, Palermo AM, Mudry MD, Carballo MA. Cytogenetic evaluation of two nitroimidazole derivatives. Toxicol In Vitro 2003; 17:35-40. [PMID: 12537960 DOI: 10.1016/s0887-2333(02)00123-6] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
5-Nitroimidazoles are a well-established group of antiprotozoal and antibacterial agents. Thanks to their antimicrobial activity these chemotherapeutic agents inhibit the growth of both anaerobic bacteria and certain anaerobic protozoa such as Trichomonas vaginalis, Entamoeba histolytica and Giardia lamblia. The aim of the present study is to achieve a precise characterization of the genotoxic activity of these compounds and to establish the value of cytogenetic assays in order to determine the effect of these drugs, at therapeutic doses, to settle an improved risk assessment. Two nitroimidazole were studied, metronidazole and ornidazole, at four different concentrations (0.1, 1, 10 and 50 microg/ml of peripheral blood lymphocyte culture). Endpoints analyzed included: mitotic index (MI), replication index (RI), sister chromatid exchange (SCE) and chromosomal aberrations (CA). An analysis of variance test (ANOVA) was performed to evaluate the results. A significant decrease (P<0.0001) in MI as well as an increase in SCE (P<0.0001) and CA (0.0001) frequencies for both drugs was observed. No modifications in RI were found. The results suggest a genotoxic and cytotoxic effect of MTZ and ONZ in human peripheral blood cultures in vitro.
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Affiliation(s)
- M M López Nigro
- CIGETOX-Citogenética y Genética Toxicológica, Dpto de Bioquímica Clínica, Facultad de Farmacia y Bioquímica (FFyB), UBA, Buenos Aires, Argentina
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27
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Bontá M, Chauviere G, Périé J, Núñez-Vergara L, Squella J. Nitro radical anions from megazol and related nitroimidazoles in aprotic media. A father–son type reaction triggered by an acidic proton. Electrochim Acta 2002. [DOI: 10.1016/s0013-4686(02)00390-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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28
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La-Scalea MA, Serrano SHP, Ferreira EI, Brett AMO. Voltammetric behavior of benznidazole at a DNA-electrochemical biosensor. J Pharm Biomed Anal 2002; 29:561-8. [PMID: 12062657 DOI: 10.1016/s0731-7085(02)00081-x] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Benznidazole is a drug used commonly as a therapeutic agent against Chagas' disease in Brazil. To clarify the cytotoxic action of benznidazole the electrochemical reduction of benznidazole has been investigated using a DNA-electrochemical biosensor, prepared by modification of a glassy carbon electrode with DNA, and the results compared with reduction at a bare glassy carbon electrode. The dependence of peak potential with pH follows slopes of 59 and 52 mV per pH unit in acid media, respectively, which corresponds to a mechanism involving the same number of electrons and protons. In neutral and alkaline solution no significant dependence of peak potential with pH was found. During the electrochemical reduction of benznidazole the formation of the hydroxylamine derivative occurs, involving a total of four electrons. The potentials for reduction were less negative when using the DNA-modified glassy carbon electrode than at the bare glassy carbon electrode although the mechanism was the same, and at pH 7.51 the peak current was four times higher than that obtained with the bare electrode. The DNA-biosensor enabled pre-concentration of the drug onto the electrode surface and the in situ damage caused to the DNA on the electrode surface by the product of benznidazole reduction could be detected electrochemically. The results are in agreement with the hypothesis that the hydroxylamine derivative is the reactive species responsible for the cytotoxic action of benznidazole.
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Affiliation(s)
- M A La-Scalea
- Departamento de Farmácia, Faculdade de Ciências Farmacêuticas, Universidade de São Paulo, Av. Prof. Lineu Prestes, 580, 05508-900 São Paulo, Brazil
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29
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Rodriguez Ferreiro G, Cancino Badías L, Lopez-Nigro M, Palermo A, Mudry M, González Elio P, Carballo MA. DNA single strand breaks in peripheral blood lymphocytes induced by three nitroimidazole derivatives. Toxicol Lett 2002; 132:109-15. [PMID: 12044544 DOI: 10.1016/s0378-4274(02)00039-5] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Tinidazole (TNZ), ornidazole (ONZ) and metronidazole (MTZ) are antiparasitic drugs (nitroimidazole derivatives) that have proven to be effective against Trichomonas vaginalis, Entoamoeba histolytica, Giardia lamblia and Helicobacter pylori. The reduction of the nitro group and the generation of short-lived reactive intermediates are the basis of its parasiticidal activity. This reduction is associated with its mutagenic activity in bacteria, although in mammalian cells DNA damage seems to be related to the production of reactive oxygen species (ROS). Using alkaline single cell electrophoresis, a significant increase in single strand breaks and alkali labile sites in human peripheral blood lymphocytes (PBL) exposed to MTZ, ONZ and TNZ at 10, 100 and 500 microg/ml is observed. MTZ causes less damage, especially at higher concentrations, when compared with TNZ, the most harmful of the drugs tested. These findings suggest that primary damage is induced under aerobic conditions and confirms that these nitroimidazoles are DNA damaging agents.
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Affiliation(s)
- Gisell Rodriguez Ferreiro
- Grupo de Genética Toxicología y Salud Ambiental, Centro de Investigaciones Biomédicas, Instituto Superior de Ciencias Medicas de la Habana, Havana, Cuba
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30
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Cyclic voltammetric studies on nitro radical anion formation from megazol and some related nitroimidazole derivatives. J Electroanal Chem (Lausanne) 2001. [DOI: 10.1016/s0022-0728(01)00557-5] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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31
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Jorgensen MA, Trend MA, Hazell SL, Mendz GL. Potential involvement of several nitroreductases in metronidazole resistance in Helicobacter pylori. Arch Biochem Biophys 2001; 392:180-91. [PMID: 11488591 DOI: 10.1006/abbi.2001.2427] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Susceptibility of Helicobacter pylori to the antibiotic metronidazole has been attributed to the activity of an oxygen-insensitive NADPH-dependent nitroreductase (RdxA), with resistance to this antimicrobial arising from null mutations in rdxA. To obtain a better understanding of the factors involved in resistance, nitroreductase and metronidazole reduction activities were investigated in matched pairs of clinical and laboratory-derived sensitive and resistant H. pylori strains. Significant differences in enzyme activities were observed between sensitive and resistant strains, suggesting that metronidazole susceptibility in H. pylori was associated with more than one enzyme activity. To establish the mutations occurring in rdxA, the genes from seventeen bacterial strains, including matched pairs were sequenced. To assess whether metronidazole was responsible for inducing random mutations in this gene, the complete nucleotide sequence of gene hp0630, encoding an NAD(P)H-quinone reductase which also has NADPH-dependent nitroreductase activity, was determined in the same strains. All resistant strains showed nonsense, missense, or frameshift mutations randomly throughout rdxA. In contrast, no mutations were observed in hp0630. The results confirmed the presence of rdxA null mutations in resistant strains and suggested that other factors involved in the metabolism of metronidazole contributed to the resistant phenotype.
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Affiliation(s)
- M A Jorgensen
- School of Microbiology and Immunology, The University of New South Wales, Sydney, NSW 2052, Australia
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32
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Tocher JH. Selective interaction of tirapazamine with DNA bases and DNA. A comparison of cyclic voltammetry and electrolysis techniques. Free Radic Res 2001; 35:159-66. [PMID: 11697196 DOI: 10.1080/10715760100300701] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
An electrochemical model has been used to study the reductive activation of the hypoxic cell cytotoxin tirapazamine (TPZ, 3-amino-1,2,4-benzotriazine-1,4-dioxide). Cyclic voltammetry and controlled potential electrolysis have been used to generate and study the 1-electron reduction product, the assumed biologically active species. Cyclic voltammetry of tirapazamine in dimethylformamide shows a quasi-reversible 1-electron reduction with the product showing a tendency to participate in a following chemical reaction. Controlled potential electrolysis to generate the 1-electron reduction product was unsuccessful due to the formation of a new redox-active species at less negative reduction potentials. However, the cyclic voltammetry of tirapazamine in the presence of E. coli DNA shows a decrease in the lifetime of the radical anion, signifying direct interaction with the DNA. The radical lifetime also decreased in the presence of adenine, thymine and guanine, but increased upon addition of cytosine and ribose. The study shows that cyclic voltammetry is an extremely useful tool for investigating the interaction between bio-reductive drugs and biological target molecules.
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Affiliation(s)
- J H Tocher
- Department of Life Sciences, University of East London, Romford Road, London E15 4LZ
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33
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Carbajo J, Bollo S, Núñez-Vergara L, Navarrete P, Squella J. Voltammetric studies of aromatic nitro compounds: pH-dependence on decay of the nitro radical anion in mixed media. J Electroanal Chem (Lausanne) 2000. [DOI: 10.1016/s0022-0728(00)00343-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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34
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35
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Mikata Y, Kishigami M, Nishida M, Yano S, Kawamoto T, Ikeuchi Y, Yoneda F. Formation of 8-oxo-7,8-dihydro-2'-deoxyguanosine under anaerobic conditions by reductively activated nitro 5-deazaflavin derivatives. Bioorg Med Chem Lett 1999; 9:2141-4. [PMID: 10465533 DOI: 10.1016/s0960-894x(99)00349-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Electrolytically reduced 6- and 8-nitro-5-deazaflavin derivatives have been found to interact to react specifically with guanine base by means of cyclic voltammetry. Electrolytic reductions of 6- and 8-nitro-5-deazaflavin derivatives in the presence of the 2'-deoxyguanosine under anaerobic conditions resulted in prominent formation of 8-oxo-7,8-dihydro-2'-deoxyguanosine.
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Affiliation(s)
- Y Mikata
- Department of Chemistry, Faculty of Science, Nara Women's University, Japan
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36
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Brett AM, Serrano SH, La-Scalea MA, Gutz IG, Cruz ML. Mechanism of interaction of in situ produced nitroimidazole reduction derivatives with DNA using electrochemical DNA biosensor. Methods Enzymol 1999; 300:314-21. [PMID: 9919533 DOI: 10.1016/s0076-6879(99)00137-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- A M Brett
- Departmento de Química, Universidade De Coimbra, Portugal
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37
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Núñez-Vergara LJ, Díaz-Araya G, Olea-Azar C, Atria AM, Bollo-Dragnic S, Squella JA. Scavenging of the one-electron reduction product from nisoldipine with relevant thiols: electrochemical and EPR spectroscopic evidences. Pharm Res 1998; 15:1690-5. [PMID: 9833989 DOI: 10.1023/a:1011948410183] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
PURPOSE To determine the formation of the one-electron reduction product from nisoldipine and its reactivity with relevant thiols in mixed medium. METHODS Cyclic voltammetry (CV) and electron paramagnetic resonance (EPR) techniques were used to determine the one-electron reduction product corresponding to the nitro radical anion. CV was employed to assess both the rate constants corresponding to the decay of the radicals and its interaction with relevant thiols. RESULTS The nisoldipine radical anion follows second order kinetics, with an association rate constant of 283+/-16 l mol(-1) sec(-1). Nitro radical anion from nisoldipine significantly reacted with thiol compounds. This reactivity was significantly higher than the natural decay of the radical in mixed medium. EPR spectra recorded in situ using DMF/ 0.1 N NaOH (pH 13) confirmed the formation of the nitro radical anion, giving a well-resolved spectra in 35 lines using 0.1 G modulation. CONCLUSIONS Electrochemical and EPR data indicated that all the tested thiols scavenged the nitro radical anion from nisoldipine. The following tentative order of reactivity towards the thiols can be proposed: cysteamine approximately glutathione > N-acetylcysteine > captopril > penicillamine.
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Affiliation(s)
- L J Núñez-Vergara
- Laboratory of Bioelectrochemistry, Faculty of Chemical & Pharmaceutical Sciences, University of Chile, Santiago.
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38
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Bailly C, Chaires JB. Sequence-specific DNA minor groove binders. Design and synthesis of netropsin and distamycin analogues. Bioconjug Chem 1998; 9:513-38. [PMID: 9736486 DOI: 10.1021/bc980008m] [Citation(s) in RCA: 215] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- C Bailly
- INSERM U-124 et Laboratoire de Pharmacologie Antitumorale Moléculaire du Centre Oscar Lambret, IRCL, Place de Verdun, 59045 Lille, France.
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39
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Petrin D, Delgaty K, Bhatt R, Garber G. Clinical and microbiological aspects of Trichomonas vaginalis. Clin Microbiol Rev 1998; 11:300-17. [PMID: 9564565 PMCID: PMC106834 DOI: 10.1128/cmr.11.2.300] [Citation(s) in RCA: 440] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Trichomonas vaginalis, a parasitic protozoan, is the etiologic agent of trichomoniasis, a sexually transmitted disease (STD) of worldwide importance. Trichomoniasis is the most common nonviral STD, and it is associated with many perinatal complications, male and female genitourinary tract infections, and an increased incidence of HIV transmission. Diagnosis is difficult, since the symptoms of trichomoniasis mimic those of other STDs and detection methods lack precision. Although current treatment protocols involving nitroimidazoles are curative, metronidazole resistance is on the rise, outlining the need for research into alternative antibiotics. Vaccine development has been limited by a lack of understanding of the role of the host immune response to T. vaginalis infection. The lack of a good animal model has made it difficult to conduct standardized studies in drug and vaccine development and pathogenesis. Current work on pathogenesis has focused on the host-parasite relationship, in particular the initial events required to establish infection. These studies have illustrated that the pathogenesis of T. vaginalis is indeed very complex and involves adhesion, hemolysis, and soluble factors such as cysteine proteinases and cell-detaching factor. T. vaginalis interaction with the members of the resident vaginal flora, an advanced immune evasion strategy, and certain stress responses enable the organism to survive in its changing environment. Clearly, further research and collaboration will help elucidate these pathogenic mechanisms, and with better knowledge will come improved disease control.
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Affiliation(s)
- D Petrin
- Department of Medicine, University of Ottawa, Ontario, Canada
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40
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Trinh S, Reysset G. Mutagenic action of 5-nitroimidazoles: in vivo induction of GC-->CG transversion in two Bacteroides fragilis reporter genes. Mutat Res 1998; 398:55-65. [PMID: 9626965 DOI: 10.1016/s0027-5107(97)00240-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The in vivo mutagenic potential of two 5-nitroimidazoles, metronidazole and dimetridazole, was evaluated in Bacteroides fragilis, a strictly anaerobic bacterium. Two antibiotic resistance genes, tetA(Q)3 and nimA, were used as DNA targets. The forward and back mutations were identified by nucleotide sequence analysis. Both drugs induced GC-->CG transversion exclusively. The results suggest that the reactive molecules generated during the intracellular reduction of the 5-nitroimidazoles are responsible for both base pair substitutions and DNA strand breaks, although the mechanisms and targets may be different.
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Affiliation(s)
- S Trinh
- Unité des Anaérobies, Institut Pasteur, Paris, France
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41
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Bailly C. Sequence-specific recognition and modification of double-helical DNA by minor-groove binding conjugates structurally related to netropsin and distamycin. ACTA ACUST UNITED AC 1998. [DOI: 10.1016/s1067-568x(98)80007-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/05/2023]
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42
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Cooper AJ, Kalinowski AP, Shoemaker NB, Salyers AA. Construction and characterization of a Bacteroides thetaiotaomicron recA mutant: transfer of Bacteroides integrated conjugative elements is RecA independent. J Bacteriol 1997; 179:6221-7. [PMID: 9335266 PMCID: PMC179533 DOI: 10.1128/jb.179.20.6221-6227.1997] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
We report the construction and analysis of a Bacteroides thetaiotaomicron recA disruption mutant and an investigation of whether RecA is required for excision and integration of Bacteroides mobile DNA elements. The recA mutant was deficient in homologous recombination and was more sensitive than the wild-type strain to DNA-damaging agents. The recA mutant was also more sensitive to oxygen than the wild type, indicating that repair of DNA contributes to the aerotolerance of B. thetaiotaomicron. Many Bacteroides clinical isolates carry self-transmissible chromosomal elements known as conjugative transposons. These conjugative transposons can also excise and mobilize in trans a family of unlinked integrated elements called nonreplicating Bacteroides units (NBUs). The results of a previous study had raised the possibility that RecA plays a role in excision of Bacteroides conjugative transposons, but this hypothesis could not be tested in Bacteroides spp. because no RecA-deficient Bacteroides strain was available. We report here that the excision and integration of the Bacteroides conjugative transposons, as well as NBU1 and Tn4351, were unaffected by the absence of RecA activity.
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Affiliation(s)
- A J Cooper
- Department of Microbiology, University of Illinois, Urbana 61801, USA.
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43
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Brett AMO, Serrano SHP, Gutz I, La-Scalea MA, Cruz ML. Voltammetric behavior of nitroimidazoles at a DNA-biosensor. ELECTROANAL 1997. [DOI: 10.1002/elan.1140091419] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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44
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Núñez-Vergara LJ, Ortiz ME, Bollo S, Squella JA. Electrochemical generation and reactivity of free radical redox intermediates from ortho- and meta-nitro substituted 1,4-dihydropyridines. Chem Biol Interact 1997; 106:1-14. [PMID: 9305405 DOI: 10.1016/s0009-2797(97)00050-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
This paper reports a comprehensive study by cyclic voltammetry on the electrochemical characteristics and the reactivity of the one-electron reduction product from a series of nitro aryl 1,4-dihydropyridines in mixed and aprotic media. In addition, the effects of 1,4-DHP on the oxygen consumption of T. cruzi epimastigotes are reported. One-electron reduction products from 1,4-DHP derivatives significantly reacted with both thiol compounds and the nuclei acid bases, adenine and uracil. This reactivity was significantly higher than the natural decay of the radicals in mixed media. Based on these results the following tentative order of reactivity towards the xeno/endobiotics is as follows: cysteamine > glutathione > adenineuracil. Both the stability and the reactivity of the nitro radical anions electrochemically generated from 1,4-DHP showed a linear dependence with pH. The sensitivity to pH of the radicals derived from o-nitro substituted derivatives was significantly higher than m-nitro substituted derivatives. On the other hand, in all cases an increase of pH produced a significant decrease in the interaction rate constant. Interaction studies carried out in aprotic media did not show any reactivity of the radicals towards both thiol compounds and the nuclei acid bases, adenine and uracil. Therefore, we concluded that the interaction process requires certain proton activity in the media. All the tested 1,4-dihydropyridines inhibited the oxygen consumption by T. cruzi epimastigotes, Tulahuén strain. The drugs with higher electron-affinity produced greater inhibition than those with lower electron-affinity (i.e. nicardipine vs nifedipine).
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Affiliation(s)
- L J Núñez-Vergara
- Laboratory of Bioelectrochemistry, Faculty of Chemical and Pharmaceutical Sciences, University of Chile, Santiago, Chile
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45
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Brett AMO, Serrano S, Gutz I, La-Scalea M. Electrochemical reduction of metronidazole at a DNA-modified glassy carbon electrode. ACTA ACUST UNITED AC 1997. [DOI: 10.1016/s0302-4598(96)05122-7] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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46
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Abstract
1. Nitroaromatic compounds are important chemotherapy agents. 2. Their selective toxicity is determined by reduction to the biologically active form in the absence of oxygen. 3. Nitroaromatics are extensively used in the treatment of anaerobic infections and to target hypoxic tumor cells in cancer therapy. 4. Possible mutagenic action is related to the relative ease of nitro group reduction. 5. The mode of action and clinical application of nitroaromatic compounds is summarized.
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Affiliation(s)
- J H Tocher
- Chemotherapy Research Unit, University of East London, UK
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47
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Brett AMO, Serrano SHP, Gutz IGR, La-Scalea MA. Comparison of the voltammetric behavior of metronidazole at a DNA-modified glassy carbon electrode, a mercury thin film electrode and a glassy carbon electrode. ELECTROANAL 1997. [DOI: 10.1002/elan.1140090204] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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48
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Núñez-Vergara LJ, Navarrete-Encina PA, Ortiz ME, Bollo S, Squella JA. Reactivity of the one-electron reduction product from nifedipine with relevant biological targets. Chem Biol Interact 1996; 101:89-101. [PMID: 8760391 DOI: 10.1016/0009-2797(96)03714-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The reactivity of the electrochemically generated nitro radical anion from nifedipine, a nitro aryl 1,4-dihydropyridine derivative, with relevant endobiotics and thiol-containing xenobiotics, was quantitatively assessed by cyclic voltammetry. The method was based on the decrease in the return-to-forward peak current ratio after the addition of compounds. A quantitative procedure to calculate the respective interaction constants between the radicals and the xeno/endobiotics is also provided. In the optimal selected conditions, i.e. mixed media (0.015 M aqueous citrate/DMF: 40/60, 0.3 M KCl, 0.1 TBAI) at pH 9.0 the following order of reactivity was obtained: glutathione > uracil > adenine and cysteamine > N-acetylcysteine > captopril > penicillamine. In all cases, the interaction rate constants for these derivatives were greater than the natural decay constant of the radical. Studies on the reactivity at pH 7.4 were also conducted. Results from these experiments indicate a significant reactivity between the radical and the endo/xenobiotics. The increase in the stability of the radical anion by increasing the pH of the mixed media resulted in a decreased reaction with the endo/xenobiotics tested. Computerized simulation with DIGISIM 2.0 of the proposed mechanisms fitted very well with the experimental results for both the natural decay of the radical and its reaction with the tested compounds.
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Affiliation(s)
- L J Núñez-Vergara
- Laboratory of Bioelectrochemistry, Faculty of Chemical and Pharmaceutical Sciences, University of Chile, Santiago, Chile
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Narcisi EM, Secor WE. In vitro effect of tinidazole and furazolidone on metronidazole-resistant Trichomonas vaginalis. Antimicrob Agents Chemother 1996; 40:1121-5. [PMID: 8723451 PMCID: PMC163276 DOI: 10.1128/aac.40.5.1121] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Trichomonas vaginalis is a common sexually transmitted protozoan parasite. Although often considered simply a nuisance infection, T. vaginalis has been implicated in premature rupture of placental membranes and increases in the risk of acquiring human immunodeficiency virus. Metronidazole, a 5-nitroimidazole, is currently the drug of choice to treat T. vaginalis infection. Because some patients have severe reactions to metronidazole and others are infected with metronidazole-resistant T. vaginalis, we were prompted to investigate alternative therapies. Tinidazole, another 5-nitroimidazole used in other countries to treat T. vaginalis infections, and furazolidone, a nitrofuran presently used to treat giardiasis and infections with some anaerobic enteric bacteria, were investigated for effectiveness against 9 metronidazole-susceptible and 12 metronidazole-resistant T. vaginalis patient isolates. The in vitro aerobic and anaerobic minimum lethal concentrations (MLC) and the time for drug efficacy were determined. Tinidazole killed the metronidazole-susceptible isolates at a low MLC but was effective against only 4 of the 12 metronidazole-resistant isolates. In contrast, furazolidone was effective at a low MLC for all isolates. When tinidazole was effective, it required > 6 h to kill trichomonads. However, furazolidone killed both metronidazole-susceptible and resistant trichomonads within 2 to 3 h of exposure. These data suggest that furazolidone may be a good candidate for treating metronidazole-resistant trichomoniasis and that further investigation of this drug is warranted.
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Affiliation(s)
- E M Narcisi
- National Center for Infectious Diseases, Centers for Disease Control and Prevention, U.S. Department of Health and Human Services, Atlanta, Georgia 30341-3717, USA
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