The Experts below are selected from a list of 60 Experts worldwide ranked by ideXlab platform
Hugo Cerecetto - One of the best experts on this subject based on the ideXlab platform.
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esr spin trapping studies of free radicals generated from Nitrofuran Derivative analogues of nifurtimox by electrochemical and trypanosoma cruzi reduction
Free Radical Research, 2003Co-Authors: Claudio Oleaazar, Juan Diego Maya, Antonio Morello, Carolina Rigol, Fernando Mendizabal, Claudio Moncada, Eliana Cabrera, Rossana Di Maio, Mercedes Gonzalez, Hugo CerecettoAbstract:Electron spin resonance (ESR) spectra of radicals obtained from two analogues of the antiprotozoal drug nifurtimox by electrolytic and Trypanosoma cruzi reduction were analyzed. The electrochemistry of these compounds was studied using cyclic voltammetry. STO 3-21G ab initio and INDO molecular orbital calculations were performed to obtain the optimized geometries and spin distribution, respectively. The antioxidant effect of glutathione on the nitroheterocycle radical was evaluated. DMPO spin trapping was used to investigate the possible formation of free radicals in the trypanosome microsomal system. Nitro1 and Nitro2 Nitrofuran analogues showed better antiparasitic activity than nifurtimox. Nitro2 produced oxygen redox cycling in T. cruzi epimastigotes. The ESR signal intensities were consistent with the trapping of either the hydroxyl radical or the Nitro2 analogue radicals. These results are in agreement with the biological observation that Nitro2 showed anti-Chagas activity by an oxidative stress mec...
Claudio Oleaazar - One of the best experts on this subject based on the ideXlab platform.
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esr spin trapping studies of free radicals generated from Nitrofuran Derivative analogues of nifurtimox by electrochemical and trypanosoma cruzi reduction
Free Radical Research, 2003Co-Authors: Claudio Oleaazar, Juan Diego Maya, Antonio Morello, Carolina Rigol, Fernando Mendizabal, Claudio Moncada, Eliana Cabrera, Rossana Di Maio, Mercedes Gonzalez, Hugo CerecettoAbstract:Electron spin resonance (ESR) spectra of radicals obtained from two analogues of the antiprotozoal drug nifurtimox by electrolytic and Trypanosoma cruzi reduction were analyzed. The electrochemistry of these compounds was studied using cyclic voltammetry. STO 3-21G ab initio and INDO molecular orbital calculations were performed to obtain the optimized geometries and spin distribution, respectively. The antioxidant effect of glutathione on the nitroheterocycle radical was evaluated. DMPO spin trapping was used to investigate the possible formation of free radicals in the trypanosome microsomal system. Nitro1 and Nitro2 Nitrofuran analogues showed better antiparasitic activity than nifurtimox. Nitro2 produced oxygen redox cycling in T. cruzi epimastigotes. The ESR signal intensities were consistent with the trapping of either the hydroxyl radical or the Nitro2 analogue radicals. These results are in agreement with the biological observation that Nitro2 showed anti-Chagas activity by an oxidative stress mec...
Jacqueline A Upcroft - One of the best experts on this subject based on the ideXlab platform.
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susceptibility in vitro of clinically metronidazole resistant trichomonas vaginalis to nitazoxanide toyocamycin and 2 fluoro 2 deoxyadenosine
Parasitology Research, 2010Co-Authors: Janelle M Wright, Linda A Dunn, Zygmunt Kazimierczuk, Anita Burgess, Kenia G Krauer, Peter Upcroft, Jacqueline A UpcroftAbstract:This study investigates the susceptibility of a clinically metronidazole (Mz)-resistant isolate of Trichomonas vaginalis to alternative anti-trichomonal compounds. The microaerobic minimal inhibitory concentration (MIC) of the 5-nitroimidazole (NI) drug, Mz, against a typical Mz-susceptible isolate of T. vaginalis is around 3.2 microM Mz while the clinically, highly Mz-resistant isolate has an MIC of 50-100 microM. This isolate was cross-resistant to other members of the 5-NI family of compounds including tinidazole and other experimental compounds and maintained resistance under anaerobic conditions. In addition, this isolate was cross-resistant to the 5-nitrothiazole compound nitazoxanide and the 5-Nitrofuran Derivative, furazolidone. Adenosine analogues toyocamycin and 2-fluoro-2'-deoxyadenosine with no nitro group were also less effective against the clinically Mz-resistant isolate than a Mz-susceptible one. Three other isolates which were determined to be Mz-resistant soon after isolation lost resistance in the long term. One other isolate has maintained some level of permanent Mz resistance (MIC of 25 microM). A multi-drug resistance mechanism may be involved in these clinically Mz-resistant isolates.
Ali Bahsas - One of the best experts on this subject based on the ideXlab platform.
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synthesis structural elucidation and in vitro antiparasitic activity against trypanosoma cruzi and leishmania chagasi parasites of novel tetrahydro 1 benzazepine Derivatives
Bioorganic & Medicinal Chemistry, 2010Co-Authors: Sandra Gomezayala, Julian Castrillon, Alirio Palma, Sandra Milena Leal, Patricia Escobar, Ali BahsasAbstract:Forty six new 1,4-epoxy-2-exo-aryl- and cis-2-aryl-4-hydroxytetrahydro-1-benzazepine Derivatives were synthesized and fully characterized. All compounds were tested in vitro against both Trypanosoma cruzi and Leishmania chagasi parasites and also for cytotoxicity using Vero and THP-1 mammalian cell lines. Many of the evaluated compounds showed remarkable activity against the epimastigote and intracellular amastigote forms of T. cruzi, with IC50 values comparable with that of control drug nifurtimox, a Nitrofuran Derivative currently used in the treatment of Chagas’ disease. Other Derivatives were found to have good activity against L. chagasi promastigotes, with low toxicity against the mammalian cells, but neither of them was active on intracellular amastigotes of L. chagasi infecting THP-1 macrophages.
Iouri Borissevitch - One of the best experts on this subject based on the ideXlab platform.
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Characteristics of the excited states of Nitrofurantoin, an anti-inflammatory and photoactive Nitrofuran Derivative
Journal of Luminescence, 2017Co-Authors: G. G. Parra, Lucimara P. Ferreira, Debora C. K. Codognato, Carla Cristina Schmitt Cavalheiro, Iouri BorissevitchAbstract:Abstract Spectral characteristics of bio and photoactive Nitrofuran Derivative drug [ N -(5-nitro-2-furfurylidene)−1-aminohydantoin], (Nitrofurantoin, NFT) were investigated using optical absorption and fluorescence spectroscopies, both in “steady-state” and time resolved forms. The irradiation of the NFT in the UV region in aqueous solution induces the fluorescence with quantum yield Φ fl ≈0.03% and lifetime τ fl ≈1 ns with these values being practically independent of the NFT protonation state. The NFT transient absorption spectrum and lifetime (τ T ) depend on the NFT protonation state with τ T being 0.04 μs for mono-protonated NFT state, 0.22 μs for its non-protonated one, and with quantum yield, Φ T ≈ 0.0001% which is practically independent of its protonation state. The quenching of this transient by molecular oxygen accompanied by simultaneous singlet oxygen formation ( 1 O 2 ) allows associate this specie with the NFT molecules in the triplet state being the efficiency of this process dependent of NFT protonation state, η pH10 ≈0.53 and η pH2.5 ≈0.07. The extremely low quantum yields, Φ fl and Φ T , and short τ fl and τ T are, probably, associated with alternative ways of the dissipation of the NFT excited state energy: the NFT photoisomerization and NO • photorelease. The synergic action of two highly reactive species such as 1 O 2 and NO • in biological medium is extremely valuable for applications in photochemotherapy, thus making NFT a potential candidate for further studies in vitro and in vivo .