Stereo- and regiospecific biotransformation of curcumenol by four fungal strains

Abstract

Biotransformations of curcumenol (1) were performed by four fungal strains, Mucor spinosus AS 3.2450, Penicillium urticae IFFI 04015, Cunninghamella echinulata AS 3.3400, Aspergillus carbonarius IFFI 02087. Five metabolites were prepared in the biotransformation process of 1, and their structures were elucidated as 15-hydroxycurcumenol (2), 1α-hydroxycurcumenol (3), 14-hydroxycurcumenol (4), 3β-hydroxycurcumenol (5) and 12-hydroxycurcumenol (6) by spectroscopic data analysis. Among them, metabolites 2–5 are novel. All of these four fungal strains showed the ability of highly stereo- and regiospecific hydroxylation for the substrate (1), which could be used as tools for preparing the hydroxylated derivatives and in vivo metabolites of curcumenol. In addition, the inhibitory effects of substrate and obtained products on nitric oxide production in lipopolysaccaride-activated macrophages were evaluated. The substrate (1) and metabolites 2, 5, and 6 showed significant inhibitory effects.