Biotransformation of isoimperatorin by Cunninghamella blakesleana AS 3.970

The biotransformation of isoimperatorin (1) by Cunninghamella blakesleana AS 3.970 yielded 6 novel products, 14-hydroxyl-isoimperatorin (2), 11-carbonyl-14-hydroxyl isoimperatorin (3), 11-carbonyl-14-hydroxyl-12,13-dihydrogen-iso-imperatorin (4), 14-hydroxyl-12,13-dihydrogenisoimperatorin (5), isoimperatorin-14-O-β-d-mannoside (6) and isoimperatorin-14-O-β-d-glucoside (7), respectively. The chemical structures of these metabolites were elucidated based on extensive spectral data including 2D NMR and HRMS. The hydroxylation, hydrogenation, carbonylation and glycosylation reactions of 1 by C. blakesleana AS 3.970 were observed in the present study. In addition, anti-osteoporosis activities of substrate and all transformed products were evaluated by using MC3T3-E1 cells. Our results suggested that hydroxylation or glycosylation of C-14 would enhance anti-osteoporosis activity significantly.

Figure optionsDownload as PowerPoint slideHighlights
► Six transformed products of isoimperatorin (1) were isolated and identified. All of them were novel compounds.
► The hydroxylation, hydrogenation, carbonylation and glycosylation reactions of 1 by Cunninghamella blakesleana were observed.
► The structure–activity relationships (SAR) of bioconversion products in anti-osteoporosis activities were discussed.