Psoralea corylifolia Lin. also known as "broken paper", "poggu fat", chives. It is a rose family, and it is an annual upright herb of legume, 60-150cm high. The leaf is single leaf, 7-8mm long; The petiole is 2-4.5cm long, the leaf is broad and ovate, the inflorescence is axillary, there are 10-30 flowers, yellow or blue corolla, the petals have a petal stalk obviously, the flag valve is inverted ovate, the pod is oval, and the flower and fruit period are 7-10 months.

Fruit is used as medicine, it has the function of tonifying kidney and strengthening yang, tonifying spleen and invigorating stomach, and can treat skin diseases such as psoriasis.

Psoralen, isopsoralen and 8-methoxypsoralen are 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. Therefore, Psoralea corylifolia can increase the speed and quantity of melanin production by increasing the activity of tyrosinase. Psoralen B can dilate blood vessels, improve local tissue nutrition, increase skin pigmentation, promote the synthesis of skin melanin, and make it sink to the subcutaneous.

1.Psoralen Extract:The vitiligo liniment 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.Psoralen Extract:Psoralen tincture, 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.Psoralen Extract:8- methoxalin liposome gel, because MOP rarely entered the blood circulation, reduced many adverse reactions (retinal toxicity and hepatotoxicity), and increased its retention time and retention in the basal layer of epidermis, thus promoting melanin synthesis.

4.Psoralen Extract:Psoralea corylifolia injection 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.