Six novel steroids from culture of basidiomycete Polyporus ellisii

Investigation of the culture of basidiomycete Polyporus ellisii led to the isolation of a novel compound 3β,9α,15α-trihydroxy-(22E,24R)-10(5→4)-abeo-ergosta-6,8(14),22-trien-5-one(1)with a new 5/7/6/5 ring system of ergosterol skeleton.In addition,five new steroids,5β,6β-epoxy-3β,7α,9α-trihydroxy-(22E,24R)-ergosta-8(14),22-dien-15-one(2),5β,6β-epoxy-3β,7α-dihydroxy-(22E,24R)-ergosta-8(14),22-dien-15-one(3),5α,6α-epoxy-3β,9α,15α-trihydroxy-(22E,24R)-ergosta-8(14),22-dien-7-one(4),15α-acetoxy-(22E,24R)-ergosta-4,6,8(14),22-tetraen-3-one(5),15β-methoxy-(22E,24R)-ergosta-4,6,8(14),22-tetraen-3-one(6),along with four known ergosterols(7-10),were obtained.All structures were elucidated based on 1D and 2D NMR spectral data.New compounds were evaluated for cytotoxicity against five human cancer cell lines,only compound 4 was found to exhibit a favorable cytotoxicity profile toward all tested tumor cell lines.