Location: Natural Products Utilization ResearchTitle: Nigrosphaerin A., a new isachromene derivative from the endophytic fungus Nigrospora sphaerica Author
Submitted to: Phytochemistry Letters
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/3/2013
Publication Date: 1/1/2014
Citation: Metwaly, A.M., Kadry, H.A., El-Hela, A.A., Mohammad, A.I., Ma, G., Culter, S.J., Ross, S.A. 2014. Nigrosphaerin A., a new isachromene derivative from the endophytic fungus Nigrospora sphaerica. Phytochemistry Letters. 7:1-5. Interpretive Summary: Fungi belonging to the genus Nigrospora have been a rich source of bioactive secondary metabolites. This work resulted in the isolation of Nigrosphaerin A, a new isochromene derivative in addition to nineteen known compounds. Four compounds showed good in vitro antileukemic activity. Three compounds showed moderate in vitro antileishmanial activity. One compound showed good antifungal activity. The result of this work could improve our goal to treat infective diseases from natural sources.
Technical Abstract: 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-ß-D- glucopyranoside. In addition nineteen known compounds (2-20) 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 0.01µg /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 .