Microbial transformation of oleanolic acid by Fusarium lini and alpha-glucosidase inhibitory activity of its transformed products.

The biotransformation of a pentacyclic triterpene, oleanolic acid (1), with Fusarium lini afforded two oxidative metabolites, 2alpha,3beta-dihydroxyolean-12-en-28-oic acid (2), and 2alpha,3beta,11beta-trihydroxyolean-12-en-28-oic acid (3). Metabolite 3 was found to be a new compound. The structures were characterized on the basis of spectroscopic studies. These metabolites exhibited a potent inhibition of alpha-glucosidase enzyme.