Six new ergosterols from the marine-derived fungus Rhizopus sp.

Six new ergosterols, including 3β-hydroxyl-(22E, 24R)-ergosta-5,8,22-trien-7,15-dione (1), 3β-hydroxyl-(22E, 24R)-ergosta-5,8,14,22-tetraen-7-one (2), 3β,15β-dihydroxyl-(22E, 24R)-ergosta-5,8(14),22-trien-7-one (3), 3β,15α-dihydroxyl-(22E, 24R)-ergosta-5,8(14),22-trien-7-one (4), 3β-hydroxyl-(22E, 24R)-ergosta-5,8(14),22-trien-7,15-dione (5), and 5α,8α-epidioxy-23,24(R)-dimethylcholesta-6,9(11),22-trien-3β-ol (6), have been isolated from the marine-derived fungus Rhizopus sp., along with four known ones (7–10). The structures of the new compounds were determined on the basis of extensive spectroscopic data. All compounds were evaluated for their cytotoxic activities on P388, A549, HL-60, and BEL-7420 cell lines by the MTT and SRB methods.