Nigrosphaerin A a new isochromene derivative from the endophytic fungus Nigrospora sphaerica

摘要

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-β-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 μg/mL, respectively and against K562 cells with IC50 values of 0.35, 0.35, 0.49 and 0.01 μg/mL, respectively. Compounds >3, >4 and >6 showed moderate antileishmanial activity with IC50 values of 30.2, 26.4 and 36.4 μg/ml, respectively. Compound >7 showed moderate antifungal activity against Cryptococcus neoformans with IC50 value of 14.8 μg/mL.