Biotransformation of 4-phenylcoumarin by transgenic hairy roots of Polygonum multiflorum

Abstract

In order to find a new method for preparation of coumarin glycosides, the glycosylation of 4-phenylcoumarin was achieved for the first time by biotransformation using transgenic hairy roots of Polygonum multiflorum. Two substrates, 7-hydroxy-4-phenylcoumarin (1) and 5,7-dihydroxy-4-phenylcoumarin (2) were synthesized through Pechmann condensation. Two biotransformed products, 4-phenylcoumarin-7-O-β-D-glucopyranoside (3) and 7-hydroxy-4-phenylcoumarin-5-O-β-D-glucopyranoside (4), biosynthesized by transgenic hairy roots ofP. multiflorum were isolated and identified using 1H-NMR, 13C-NMR, HMBC and ESI-MS spectral technologies. Biosynthesis product 4 was a novel compound. Co-culture time curve on conversion was also established. Time course experiment revealed that the optimal co-culture time of compounds 1 and 2 was 4 and 2 day, respectively. In conclusion, biotransformation was shown to be an effective method to prepare 4-phenylcoumarin glycoside. Key words: Biotransformation, 4-phenylcoumarin, Polygonum multiflorum, transgenic hairy roots.