To develop a new skin whitening agent, arbutin-beta-glycosides were synthesized and evaluated for their melanogenesis inhibitory activities. Three active compounds were synthesized via the transglycosylation reaction of Thermotoga neapolitana beta-glucosidase and purified by recycling preparative HPLC. As compared with arbutin (IC(50 )= 6 mM), the IC(50 )values of these compounds were 8, 10, and 5 mM for beta-D -glucopyranosyl-(1-->6)-arbutin, beta-D: -glucopyranosyl-(1-->4)-arbutin, and beta-D -glucopyranosyl-(1-->3)-arbutin, respectively. beta-D: -Glucosyl-(1-->3)-arbutin also exerted the most profound inhibitory effects on melanin synthesis in B16F10 melanoma cells. Melanin synthesis was inhibited to a significant degree at 5 mM, at which concentration the melanin content was reduced to below 70% of that observed in the untreated cells. Consequently, beta-D: -glucopyranosyl-(1-->3)-arbutin is a more effective depigmentation agent and is also less cytotoxic than the known melanogenesis inhibitor, arbutin.

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