Antileukemic, Antileishmanial and Antifungal Activities of Secondary Metabolites from the Endophytic Fungus Nigrospora sphaerica
In this study, in vitro antileukemic, antileishmanial, antifungal and antibacterial activities of secondary metabolites (1 – 11) isolated from the endophytic fungus Nigrospora sphaerica were examined. The endophytic fungus Nigrospora sphaerica was isolated from Vinca rosea (Apocynaceae) leaves growing in Egypt. The isolated compounds were chemically identified as ergosta-6,22-diene-3β,5α,8α-triol (1) , ergosta-7,22-diene-3β-ol (2), ergosta-4,6,8 (14),22-tetraene-3β-ol (3), ergosta-4,6,8 (14),22 tetraene-3-one (4), ergosta-5,7,22-triene-3β-ol (5), ergosta-6,22-diene-5,8 epoxide-3β-ol (6), ergosta-7,22-epoxy-3β-ol (7), 4-(hydroxymethyl) -3,5-dimethyl dihydrofuran-2(3 H)-one (8), 3- (1-hydroxyethyl) -4-methyl dihydrofuran-2(3 H)-one (9), uridine (10) and adenosine (11). All compounds (except 4 and 6) were isolated for the first time from this fungus. Four fatty acids have been also isolated and chemically identified as stearic acid, oleic acid, palmitic acid, and myristic acid using GC/MS. Compounds 5, 6 and 8 showed good antileukemic activity against HL60 Cells with IC50 values of 0.03, 0.39 and 0.2 µg/mL, respectively and against K562 cells with IC50 values of 0.35, 0.35, and 0.49 µg/mL, respectively. Compounds 2, 3 and 5 showed moderate antileishmanial activity with IC50 values of 30.2, 26.4 and 36.4 µg/mL, respectively. Compound 6 showed antifungal activity against Cryptococcus neoformans with an IC50 value of 14.8 µg/mL.