Bioautography Guided Identification of Anticandidal Compounds from A. terreus st. 1

Abstract

Problem statement: Saprophytic and soil inhabiting microorganisms are prolific producers of secondary metabolites with wide range of structural and functional diversity. The objective of the current study was to screen and evaluate the anti-candidal properties of soil inhabiting fungi. Approach: Preliminary dual culture assay and bioautography was used to screen the fungi with potential anti-fungal activity and direct detection of antifungal compound/fraction in microbial extract on thin layer chromatograms, respectively. Disk diffusion, broth dilution and germ tube inhibitory assay were used to evaluate and confirm the anticandidal activity. Partial characterization of purified extract was carried out using High Performance Liquid Chromatography (HPLC) and Fast Performance Liquid Chromatography (FPLC) techniques. Result and Discussion: A. terreus was found to produce compound with anti-candidal and germ tube inhibitory activity against human pathogen Candida albicans at 200 mg ml^-1. Further proteinase inhibitory activity of the extract, tested using plate assay and SDS-PAGE ensures the anti-candidal activity of the extract. Present study identified and confirmed the potential anticandidal activity, interms of germ tube and proteinase inhibititory activity, of metabolites produced by A. terreus st.1. Conclusion: The bio-assay guided fractionation and purification resulted in identification of unique fraction with active anti-candidal activity. Thus this fraction may serve as one of the lead to develop novel anti-candidal therapeutics.