Identification of Obscurolide-Type Metabolites and Antifungal Metabolites from the Termite-Associated Streptomyces neopeptinius BYF101

초록

Streptomyces spp. are well-known symbioticmicroorganismsthat produce antimicrobial metabolites against various pathogens.We isolated actinomycetes from the body surface of the termite Odontotermes formosanus and identified it as Streptomycesneopeptinius BYF101 based on 16S rRNA phylogenetic analysis.Chemical analysis of the cultures of termite-associated S.neopeptinius BYF101 via HR-MS2 and GNPS analysesenabled the isolation and identification of 20 metabolites, includingthe unreported obscurolide-type metabolites (1-3). The chemical structures of unreported compounds (1-3) were elucidated using HR-ESI-MS and1D and 2D NMR analysis, and their absolute configurations were determinedvia chemical reactions followed by the application of competing enantioselectiveacylation (CEA) and computational methods for ECD and DP4+ probabilitycalculation. The isolated compounds (1-20) were tested to determine their antifungal activity against twohuman fungal pathogens, Candida albicans and Cryptococcus neoformans. Among the compounds tested, indole-3-carboxylicacid (9) displayed antifungal activity against C. neoformans, with an MIC value of 12 & mu;g/mL.

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