Enzymatic synthesis of resveratrol α-glucoside by amylosucrase of Deinococcus geothermalis .

Glycosylation of resveratrol was carried out by using the amylosucrase of Deinococcus geothermalis, and the glycosylated products were tested for their solubility, chemical stability, and biological activities. Two major glycosylated products were synthesized and identified as resveratrol-4'-O-α-glucoside and resveratrol-3-O-α-glucoside by nuclear magnetic resonance analysis with a ratio of 5:1. The water solubilities of two resveratrol-α-glucoside isomers (α-piceid isomers) were approximately 3.6 and 13.5 times higher than that of s-piceid and resveratrol, respectively, and highly stable in buffered solutions. The antioxidant activity of α-piceid isomers was examined by radical scavenging capability. The radical scavenging activity of α-piceid isomers was initially lower than that of resveratrol, but as time passed, the activity of α-piceid isomers became similar to that of reseveratrol. The α-piceid isomers also showed better tysoinase inhibitory activity and inhibition capability for melanin synthesis in B16F10 melanoma cells than s-piceid. The cellular uptake of α-piceid isomers, which was assessed by ultra-performance liquid chromatography analysis of the cell-free extracts of B16F10 melanoma cells, demonstrated that the glycosylated form of resveratrol was gradually converted to resveratrol inside the cells. These results indicate that the enzymatic glycosylation of resveratrol will be a useful method for the enhancement of the bioavailability of resveratrol.