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

Abstract A novel polyhydroxylated C 29 -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 ( 1 H– 1 H COSY, HSQC, HMBC, and NOESY) experiments and comparison with the literature. Globosterol ( 1 ) possesses an unprecedented 25-methyl Δ 22 -C 10 -side chain and Δ 7 -3β,6β,9α-hydroxy-steroid nucleus, which represents the first example for C 29 -steroids of the group.