Non-terpenoid biotransformations by Mucor species

Biotransformation is an important tool for the structural modification of organic compounds, especially natural products with complex structures, which are difficult to achieve using ordinary methods. It is also useful as a model for mammalian metabolism due to similarities between mammalian and microbial enzyme systems. The development of novel biocatalytic methods is a continuously growing area of chemistry, microbiology, and genetic engineering, and novel microorganisms and/or their enzymes are being screened intensively. This review covers the transformation of non-terpenoid compounds such as steroids, coumarins, flavonoids, drugs, pesticides and others by Mucor spp. up to the end of 2012

Evaluation of dispersive liquid–liquid microextraction in the stereoselective determination of cetirizine following the fungal biotransformation of hydroxyzine and analysis by capillary electrophoresis

AbstractWe developed a capillary electrophoresis (CE) and dispersive liquid–liquid microextraction (DLLME) method to stereoselectively analyze hydroxyzine (HZ) and cetirizine (CTZ) in liquid culture media. The CE analyses were performed on an uncoated fused-silica capillary; 50mmolL−1 sodium borate buffer (pH 9.0) containing 0.8% (w/v) S-β-CD was used as the background electrolyte. The applied voltage and temperature were +6kV and 15°C, respectively, and the UV detector was set to 214nm. Chloroform (300µL) and ethanol (400µL) were used as the extraction and disperser solvents, respectively, for the DLLME. Following the formation of a cloudy solution, the samples were subjected to vortex agitation at 2000rpm for 30s and to centrifugation at 3000rpm for 5min. The recoveries ranged from 87.4 to 91.7%. The method was linear over a concentration range of 250–12,500ngmL−1 for each HZ enantiomer (r>0.998) and 125–6250ngmL−1 for each CTZ enantiomer (r>0.998). The limits of quantification were 125 and 250ngmL−1 for CTZ and HZ, respectively. Among the six fungi studied, three species were able to convert HZ to CTZ enantioselectively, particularly the fungus Cunninghamella elegans ATCC 10028B, which converted 19% of (S)-HZ to (S)-CTZ with 65% enantiomeric excess

Estudo comparativo de técnicas de screening para avaliação da atividade anti-bacteriana de extratos brutos de espécies vegetais e de substâncias puras

In this work, the effectiveness of four screening techniques (three techniques of the diffusion method and one microdilution broth method) were compared. Evaluated were the ethanolic and dichloromethanic extracts of Miconia rubiginosa (Melastomataceae) against six standard bacteria (ATCC). The results showed statistical disagreement among the three diffusion techniques. Among the diffusion techniques, the well technique displayed the best result. However the microdilution broth method demonstrated to be the most adequate method to evaluate the antibacterial activity of plant crude extracts and pure compounds when compared to the other methodologies

Terpenoid biotransformations by Mucor species

Terpenoids are natural products of great interest due to their widespread use in agrochemicals, drugs, fragrances, flavouring and pigments. Biocatalysts are increasingly being used in the search for new derivatives with improved properties especially to obtain structurally novel leads for new drugs which are difficult to obtain using conventional organic chemical methods. This review, covering up to the end of 2012, reports on the application of Mucor species as catalysts in terpenoid biotransformation to obtain new drug targets, enhance pharmacological activity or decrease the unwanted effects of starting material

The potential of an Aspergillus fumigatus Brazilian strain to produce antimicrobial secondary metabolites O potencial de uma cepa brasileira de Aspergillus fumigatus para produzir metabólitos secundários antimicrobianos

During the course of screening for biologically leading active natural products from fungi, a strain of Aspergillus fumigatus was assessed for antimicrobial activity production. Four parameters consisting of medium culture, pH, temperature and time of fermentation were investigated. The extracts from the fungus cultures displayed different TLC profiles and produced, at least, one inhibition zone in the bioautography assays. Overlapping inhibition zones in the range of Rf 0.09 to 0.65 against Kocuria rhizophila were detected in the bioautography assay of the chloroform extract obtained from Jackson's medium culture, initial pH of 6.0 and incubation at 40ºC for 144 hours. However, the obtained extracts by developing the fungus culture in Vogel's medium furnished the smallest number of active compounds. The obtained chromatographic profiles of the extracts from the fungus cultures by high performance liquid chromatography with photodiode array detector were distinctive, allowing to infer that A. fumigatus secondary metabolites production could be affected by modifying any of the undertaken parameters. It should be pointed out that a remarkable difference among HPLC profiles was observed by using different media culture.<br>Em estudos desenvolvidos para encontrar produtos naturais biologicamente ativos provenientes de fungos, uma cepa de Aspergillus fumigatus foi avaliada para a produção de atividade antimicrobiana. Quatro parâmetros, consistindo de meio de cultura, pH, temperatura e tempo de fermentação, foram investigados. Os extratos obtidos das culturas do fungo apresentaram perfis cromatográficos diferentes e produziram, ao menos, uma zona de inibição quando avaliados por bioautografia. Zonas de inibição sobrepostas na faixa de Rf 0.09 a 0.65, contra Kocuria rhizophila, foram detectadas na bioautografia do extrato clorofórmico obtido da cultura desenvolvida no meio de Jackson, pH inicial 6,0 e incubação a 40ºC por 144 horas. Entretanto, os extratos obtidos por desenvolver a cultura do fungo no meio de Vogel forneceram o menor número de compostos ativos. Os perfis cromatográficos obtidos dos extratos das culturas do fungo por cromatografia líquida de alta eficiência com detector de arranjo de diodos foram distintos, permitindo inferir que a produção de metabólitos secundários por Aspergillus fumigatus pode ser afetada pela modificação dos parâmetros investigados. Deve ser ressaltado que uma notável diferença nos perfis cromatográficos obtidos por CLAE foi observada por utilizar diferentes meios de cultura

Antimicrobial potential of Casearia sylvestris against oral bacteria

Abstract Aim The aim of this study was to obtain Casearia sylvestris leave extracts by different extractive methods, including the obtention of essential oil, in order to compare their antimicrobial activities to conventional mouthwash chlorhexidine against oral bacteria. Material and method For this evaluation, extracts from the leaves were obtained by different methods of extraction (infusion, decoction, maceration and percolation) using different solvent systems: water 100%, ethanol 100%, methanol 100%, water: ethanol 3:7; water: ethanol 7:3; water: methanol 7:3 and water: methanol 3:7. The essential oil, which corresponds to a volatile fraction, was obtained by hydrodistillation using Clevenger modified apparatus. The microdilution broth method was used to determine the values of minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) for the following microorganisms: Streptococcus mutans ATCC 25175, S. mitis ATCC 49456, S. sanguinis ATCC 10556, S. salivarius ATCC 25975, Lactobacillus casei ATCC 11578 and Enterococcus faecalis ATCC4082. Chlorhexidine gluconate was used as a positive control. Result All extracts evaluated in the used protocol displayed MIC values higher than 400 µg/mL and few showed bactericidal activity. The antimicrobial activity of essential oil was higher than the activity of the extracts, and the best minimum inhibitory concentration and minimum bactericidal concentration values were obtained against L. casei (MIC of 0.023 µg/mL and MBC of 0.046 µg/mL) and S. mutans (MIC of 25 µg/mL and MBC of 50 µg/mL), respectively. Conclusion The essential oil of Casearia sylvestris has significant antimicrobial activity against oral microorganisms

Assessment of the stereoselective fungal biotransformation of albendazole and its analysis by HPLC in polar organic mode

A high-performance liquid chromatographic method using polar organic mode was developed to analyze albendazole (ABZ), albendazole sulfone (ABZSO(2)) and the chiral and active metabolite albendazole sulfoxide (ABZSOX, ricobendazole) that was further applied in stereoselective fungal biotransformation studies. The chromatographic separation was performed on a Chiralpak AS column using acetonitrile:ethanol (97:3, v/v) plus 0.2% triethylamine and 0.2% acetic acid as the mobile phase at a flow rate of 0.5 mL min(-1). The present study employed hollow fiber liquid-phase microextraction as sample preparation. The method showed to be linear over the concentration range of 25-5000 ng mL(-1) for each ABZSOX enantiomer, 200-10,000 ng mL(-1) for ABZ and 50-1000 ng mL(-1) for ABZSO(2) metabolite with correlation coefficient (r)&gt; 0.9934. The mean recoveries for ABZ, rac-ABZSOX and ABZSO(2) were, respectively, 9%, 33% and 20% with relative standard deviation below 10%. Within-day and between-day precision and accuracy assays for these analytes were studied at three concentration levels and were lower than 15%. This study opens the door regarding the possibility of using fungi in obtaining of the active metabolite ricobendazole. Nigrospora sphaerica (Sacc.) E. W. Mason (5567), Pestalotiopsis foedans (VR8), Papulaspora immersa Hotson (SS13) and Mucor rouxii were able to stereoselectively metabolize ABZ into its chiral metabolite. Among them, the fungus Mucor rouxii was the most efficient in the production of (+)-ABZSOX. (C) 2011 Elsevier B.V. All rights reserved.Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq)CNPq (Conselho Nacional de Desenvolvimento Cientifico e Tecnologico