Microbial transformation of osthole by human intestinal fungi and anti-osteoporosis activities of its metabolites

Osthole is one of the major constituents in Cnidium monnieri (L.) Cuss. and possesses anti-osteoporosis activity. In this work, the biotransformation of osthole was performed based on the human intestinal fungi Mucor circinelloides. Six metabolites including three new metabolites (S2, S3, S4) were obtained, and their chemical structures were elucidated by spectroscopic data analysis. The major biotransformation reactions involved hydroxylation and glycosylation. In addition, all metabolites were evaluated for their anti-osteoporosis activity using MC3T3-E1 cells. The results demonstrated that S4, S5 and S6 could significantly promote MC3T3-E1 cell growth compared to osthole.