In this study, two quercetin-α-d-glucopyranosides were synthesized via the acceptor reaction of a glucansucrase obtained from Leuconostoc mesenteroides B-1299CB, with quercetin and sucrose. The two transfer products were purified via HPLC, and the structures of the products were identified as quercetin-4′-O-α-d-glucopyranoside (Q-G1) and quercetin-3′-O-α-d-glucopyranoside (Q-G1′), in accordance with the results of 1 H, 13 C, HSQC, H-H COSY, HMBC analyses. The primary product (Q-G1) evidenced slower effects on DPPH radical-scavenging activity (SC 50 =25.2μM) than was seen with quercetin (SC 50 =6.5μM). The water solubility of Q-G1 was 12.7mM, whereas the quercetin was barely soluble in water. The K i value of Q-G1 (674.5μM) was almost identical to that of quercetin (673.3μM) with regard to tyrosinase inhibition effects.