Biotransformation of osthole by Mucor spinosus

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), ostheno1-7-O-beta-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 D-2 NMR and MS spectroscopy. Among them, metabolites 6 and 8 were new. The hydroxylation, dehydrogenation, demethylation and glycosylati on 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. (C) 2012 Elsevier Ltd. All rights reserved.