A novel acylated quercetin glycoside and compounds of inhibitory effects on α-glucosidase from Panax ginseng flower buds

A novel acylated quercetin glycoside, floralpanasenoside A (1) and five known flavonoid glycosides, panasenoside (2), quercetin 3-O-(2''-β-D-glucopyranosyl)-β-D- galactopyranoside (3), trifolin (4) kaempferol 7-O-α-L-rhamnoside (5), and afzelin (6) were isolated from the flower buds of Panax ginseng. Their structures were established by spectroscopic data and comparison with the literature values. Four of the six isolated compounds including 1 (IC50 = 62.4) exhibited α-glucosidase inhibitory activity with IC50 values lower than acarbose (385.2 μM). The molecular docking study indicated that 1 bound to the active site of α-glucosidase with numerous hydrogen bond interactions.