Inhibitory effects of hydroquinone-α-glucoside (HQ-α-G) on the melanogenesis were investigated and compared with those of arbutin. The levels of inhibitory effects of HQ-α-G and arbutin on the tyrosinase activity were nearly the same. Inhibitory effects of both compounds on the melanogenesis, were studied using cultured B16 melanoma cells, and HQ-α-G was also found to have a similar effect to that of arbutin without inhibiting cell growth. In this experiment, while HQ-α-G hardly inhibited cell growth at 1 mM, arbutin inhibit it significantly at the same concentration. From these results it is suggested that HQ-α-G as well as arbutin inhibited the melanogenesis by affecting tyrosinase rather than by killing melanocytes. Furthermore, the melanogenesis of guineapigs with brown hair was reduced to about 80% by applying them each compound. The great differences in toxicity to normal human keratinocyte were not recognized between these two glucosides. It is, therefore, considered that HQ-α-G is an effective and safe ingredient for cosmetics.
