中文摘要：

目的：评价甘草提取物对人原代黑素细胞酪氨酸酶及黑素合成的影响。方法：选择2．5、5．0、10．0、15．0、20．0、30．0mg／L6个浓度的甘草作用于体外培养的人表皮黑素细胞72h，分别测定细胞增殖活性、酪氨酸酶活性和黑素含量，western blot方法检测甘草作用后黑素细胞中酪氨酸酶蛋白的表达。结果：甘草显著抑制黑素合成和酪氨酸酶活性，且呈浓度依赖性。结论：甘草通过下调酪氨酸酶的表达抑制黑素合成和酪氨酸酶活性。

英文摘要：

Objective： To assess the effects of licorice on melanin synthesis. Methods： Normal human melanocytes were isolated from human forskin and incubated with 2.5, 5.0, 10.0, 15.0, 20.0 and 30.0 pg/mL licorice for 72 h respectively, in vivo. The proliferation of melanocytes, melanin content and tyrosinase activity were measured. The protein expression of tyrosinase was evaluated with western blot technique. Results： Melanin synthesis was reduced and tyrosinase activity was significantly inhibited when licorice was cultured with melanocytes in a dose dependent manner, compared to control group. Conclusion： Licorice can inhibit melanogenesis and tyrosinase activity through downregulating the expression of tyrosinase.