Project description:BackgroundEndophyte bestows beneficial aspects to its inhabiting host, along with a contribution to diverse structural attributes with biological potential. In this regard, antimicrobial profiling of fungal endophytes from medicinal plant Adiantum philippense revealed bioactive Nigrospora sphaerica from the leaf segment. Chemical and biological profiling through TLC-bioautography and hyphenated spectroscopic techniques confirmed the presence of phomalactone as an antimicrobial metabolite.ResultsThe chemical investigation of the broth extract by bioassay-guided fractionation confirmed phomalactone as a bioactive antimicrobial secondary metabolite. The antimicrobial activity of phomalactone was found to be highest against Escherichia coli by disc diffusion assay. The MIC was found to be significant against both Escherichia coli and Xanthomonas campestris in the case of bacteria and dermatophyte Candida albicans at 150 μg/ml, respectively.ConclusionsOverall, the results highlighted the antimicrobial potential of phomalactone from the endophyte Nigrospora sphaerica exhibiting a broad spectrum of antimicrobial activity against human and phytopathogenic bacteria and fungi. This work is the first report regarding the antibacterial activity of phomalactone.
Project description:Nigrosphaerin A, a new isochromene derivative (1), was isolated from the endophytic fungus Nigrospora sphaerica and chemically identified as 3-(3,4-dihydroxyphenyl)-4,6,8-trihydroxy-1H-isochromen-1-one-6-O-?-d-glucopyranoside. In addition nineteen known compounds (2-20) were isolated from the same fungus and chemically identified. Compounds (1-3, 5, and 7-16) were isolated for the first time from this fungus. In vitro antileukemic, antileishmanial, antifungal, antibacterial and antimalarial activities of (1-20) were examined. Compounds 5, 7, 9 and 10 showed good antileukemic activity against HL60 cells with IC50 values of 0.03, 0.39, 0.2 and 0.4 ?g/mL, respectively and against K562 cells with IC50 values of 0.35, 0.35, 0.49 and 0.01 ?g/mL, respectively. Compounds 3, 4 and 6 showed moderate antileishmanial activity with IC50 values of 30.2, 26.4 and 36.4 ?g/ml, respectively. Compound 7 showed moderate antifungal activity against Cryptococcus neoformans with IC50 value of 14.8 ?g/mL.
