Biotransformation of osthole by Mucor spinosus

Abstract

Osthole (1) as a natural product, has the potent anti-osteoporosis activity. In the present paper, a scaled-up biotransformation of 1 by Mucor spinosus AS 3.3450 was carried out for improving its activities and water-solubility. Nine metabolites were obtained in the biotransformation process of 1, and their structures were elucidated as 4′-hydroxyl-osthole (2), osthenol (3), osthenol-7-O-β-d-glucoside (4), 5′-hydroxyl-osthole (5), 5′-hydroxyl-2′,3′-dihydro-osthole (6), 2′,3′-dihydroxyl-osthole (7), 2′-ketone-3′-hydroxyl-osthole (8), 2′-acetoxy-3′-hydroxy-osthole (9) and 2′-hydroxyl-isoothole (10), on the basis of extensive spectral data including 2D NMR and MS spectroscopy. Among them, metabolites 6 and 8 were new. The hydroxylation, dehydrogenation, demethylation and glycosylation reactions of 1 by M. spinosus AS 3.3450 were reported in the present study. And anti-osteoporosis activities of all products were also evaluated by using MC3T3-E1 cells.