Polyhydroxylated steroids from an endophytic fungus, Chaetomium globosum ZY-22 isolated from Ginkgo biloba

A novel polyhydroxylated C29-sterol, 25ξ-methyl-22-homo-5α-cholest-7,22-diene-3β,6β,9α-triol, designated globosterol (1), together with one known tetrahydroxylated ergosterol (22E, 24R)-ergosta-7,22-diene-3β,5α,6β,9α-tetraol (2) has been isolated from the cultures of an endophytic fungus, Chaetomium globosum ZY-22 originated from the plant Ginkgo biloba. The structures and relative configurations of 1 and 2 were established on the basis of extensive spectroscopic analyses including 1D and 2D NMR (1H–1H COSY, HSQC, HMBC, and NOESY) experiments and comparison with the literature. Globosterol (1) possesses an unprecedented 25-methyl Δ22-C10-side chain and Δ7-3β,6β,9α-hydroxy-steroid nucleus, which represents the first example for C29-steroids of the group.