Our previous study on whitening constituents-containing plants showed that the inhibition of melanin synthesis for KC-2T (100 ug╱mL) was stronger than that of arbutin (2.72 mg╱mL). KC-2T was derived from Psychotria rubra (LOUR.) POIR. of Rubiaceae after suitable extraction and treatment. In this project, the safety of KC-2T cytotoxicity, the eye irritation test and primary skin irritation test were carried out. The results showed that KC-2T was non-cytotoxicity, mild irritation and non-skin irritation. In the first year project, vanillic acid (16.8 mg╱mL), the constituent in the plant containing Psychotria rubra (LOUR.) POIR., showed stronger inhibition of tyrosinase activity by means of inhibition zone test than that of arbutin (27.2 mg╱mL). In this project, the mechanisms of whitening effect of vanillic acid were studied. The result showed that vanillic acid had no good effect on the synthesis of tyrosinase. However, vanillic acid had inhibitory effect on tyrosinase activity in B16 mouse cell.
