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

One new isochromene derivative along with nineteen known compounds was isolated from the endophytic fungus Nigrospora sphaerica. Four compounds showed good antileukemic activity. Three compounds showed moderate antileishmanial activity. One compound showed good antifungal activity. •The phytochemical and biological properties of the endophytic fungus Nigrospora sphaerica were examined. Nigrosphaerin A, a new isochromene derivative, along with nineteen known compounds was isolated and identified. Four compounds showed good in vitro antileukemic activity. Three compounds showed moderate in vitro antileishmanial activity. One compound showed good antifungal activity. 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 0.4μg/mL, respectively and against K562 cells with IC50 values of 0.35, 0.35, 0.49 and 0.01μg/mL, respectively. Compounds 3, 4 and 6 showed moderate antileishmanial activity with IC50 values of 30.2, 26.4 and 36.4μg/ml, respectively. Compound 7 showed moderate antifungal activity against Cryptococcus neoformans with IC50 value of 14.8μg/mL.