Microbial glycosylation of cardamonin by Mucor spinosus

Microbial transformation of cardamonin by Mucor spinosus (CGMCC 3.3450) in preparative scale resulted in the isolation of two new products.  Their structures were elucidated unambiguously by ESI-MS, ¹H NMR, ¹³C NMR and 2D NMR spectra analyses as 4-O-β-D-glucopyranosyl-6-hydroxy-2-methoxychalcone (1, 4-GluC) and 6-O-β-D-glucopyranosyl-4-hydroxy-2-methoxychalcone (2, 6-GluC), respectively.  The time-course of biotransformation by M. spinosus showed that both 4-GluC and 6-GluC appeared on the 2^nd day.  The optimal biotransformation temperature was 28 ℃, the optimal biotransformation time was 72 h and the optimal concentration for cardamonin was 40 mg·mL⁻¹.  This is the first time for successful microbial glycosylation of cardamonin in present research.