Microbial transformation of methyl protodioscin by Cunninghamella elegans

Biotransformation of methyl protodioscin (1) by Cunninghamella elegans (AS 3.1207) was investigated. Nine bioconversion products were isolated and identified. Eight of the bioconversion products were pregnane glycoside or steroidal saponins. It was found that steroidal saponin skeleton could be converted to pregnenolone skeleton only using microbial methods, which must have chemical procedures in the reported literatures. The found enriched the types of bioconversion reaction and provided a new way for the production of androstenedione. Most bioconversion products showed considerable cytotoxic activities against HepG2, NCI-H460, MCF-7 and HeLa cell lines compared to methyl protodioscin.