表没食子儿茶素没食子酸酯对人表皮黑素细胞黑素合成的影响及机制

Effects of epigallocatechin-3-gallate on melanogenesis of human epidermal melanocytes

目的:观察表没食子儿茶素没食子酸酯(EGCG)对体外培养的人表皮黑素细胞的黑素合成和酪氨酸酶(TYR)活性以及TYR、酪氨酸酶相关蛋白(TRP)-1、TRP-2mRNA表达的影响,探讨EGCG对黑素合成的影响及其作用机制。方法:选择5.0、10.0、12.5、15.0、20.0μg/mL5个浓度的EGCG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、TYR活性、黑素含量;采用逆转录(RT)-PCR半定量检测EGCG对黑素细胞中TYR、TRP-1、TRP-2mRNA表达的影响。结果:EGCG显著抑制黑素合成和TYR活性,且呈浓度依赖性;EGCG可明显抑制黑素细胞中TYRmRNA和TRP-1mRNA的表达,但对TRP-2mRNA的表达无明显影响。结论:EGCG可抑制黑素合成和TYR活性,这种作用可能与EGCG下调TYR和TRP-1的表达有关。

Objective： To observe the effects of epigallocatechin-3-gallate （EGCG） on melanin synthesis and to study the its mechanism of depigmentation. Methods： Normal human melanocytes were isolated from human foreskin. Melanocytes were incubated with 5.0, 10.0 12.5, 15.0 and 20.0 μg/mL EGCG for 72 h respectively. The rate of proliferation, melanin content, and tyrosinase activity were measured. The mRNA expressions of tyrosinase, tyrosinase related protein （TRP） 1 and 2 were evaluated with RT-PCR. Results： The results showed that EGCG inhibited melanin synthesis and tyrosinase activity significantly compared with control. EGCG decreased the cellular melanin content in dose dependent manner and inhibited the expression of tyrosinase and TRP1, but had no effect on TRP2. Conclusions： EGCG can inhibit melanogenesis and the ac tivity of tyrosinase. This effectiveness may be induced by the downregulations of the tyrosinase and TRP1 mRNA.