Bakuchiol is photosensitive substances in Psoralea corylifolia. Therefore, UVA combined with sunshine or topical irradiation can promote the formation of skin melanin. Psoralea corylifolia can activate tyrosinase up to 44.9%. Psoralea corylifolia extract of 95% ethanol has obvious activation on tyrosinase, and tyrosinase is the key enzyme of melanin synthesis in human body. 

1. Bakuchiol composed of psoralen, plum, Angelica dahurica, cinnamon and other multiflavor drugs has the function of warming meridians and dredging collaterals, nourishing blood and dispelling wind; while 8-methoxypsoralen 0.05%/ml and acetic acid skin relaxant 0.0125%/ml can be used externally to treat vitiligo, with definite curative effect and good clinical effect.

2. Bakuchiol, which is mainly prepared by psoralen and isopsoralen, can increase tyrosinase activity in melanocytes, promote biochemical synthesis and operation of melanin, and promote skin color to return to normal.

3.Bakuchiol contains 8-methoxypsoralen, which can increase the sensitivity of skin to ultraviolet radiation. After ultraviolet irradiation, it can effectively inhibit DNA synthesis of epidermal keratinocytes, thereby inhibiting excessive proliferation of psoriatic keratinocytes and achieving therapeutic purposes.