茶叶提取物EGCG和GCG及ECG对B16细胞内黑色素生成的抑制作用

为研究茶叶提取物表没食子儿茶素没食子酸酯(epigallocatechin gallate,EGCG)、没食子儿茶素没食子酸酯(gallocatechingallate,GCG)和表儿茶素没食子酸酯(epicatechingallate,ECG)对体外培养B16小鼠黑色素瘤细胞黑色素生成及酪氨酸酶活性的影响,分别用不同浓度的EGCG、GCG、ECG和熊果苷(Arbutin,AR)处理细胞,观察效应物对细胞形态的影响,用溴化二苯四偶氮法(MTT法)测定茶叶提取物对细胞增殖率的影响,以左旋多巴(L–DOPA)为底物,测定细胞内酪氨酸酶的活性,采用氢氧化钠裂解法测定细胞内黑色素的含量。结果显示,EGCG、ECG、GCG能显著抑制B16细胞的黑色素生成和酪氨酸酶的活性,且呈剂量依赖关系;当浓度为60μg/mL时,细胞增殖率均低于50%,酪氨酸酶活性与对照组相比分别降低了26.67%、27.27%和32.71%,黑色素生成抑制率均在30%以上。结果表明,茶叶提取物能通过多种途径抑制黑色素生成,且GCG的作用效果最优,ECG的作用效果次之,三者的作用效果均优于熊果苷的作用效果。

Inhibitory effects of tea extracts EGCG,GCG and ECG on the melanogenesis in melanoma cell B16

Inhibitory effects of tea extracts EGCG, GCG and ECG on melanoma cell B16 from mouse were studied in this paper. Cells were treated with different concentrations of GCG, ECG, EGCG and Arbutin, and their morphology was observed in an inverted microscope. The proliferation rate of B16 was determined using MTT method, tyrosinase activity was detected by using L-DOPA as substrate, and NaOH-lysis approach was employed to measure the melanin synthesis. The results showed that EGCG, ECG, GCG could significantly inhibit the melanogenesis and tyrosinase activity in cells B16 with a dose-dependent manner. The proliferation rate would be lower than 50% when the concentration was increased to 60 μg/mL. Compared with the control group, tyrosinase activities affected by the three substances were reduced by 26.67%, 27.27% and 32.71%, respectively, the melanin inhibition rates were all above 30%. In conclusion, tea extracts could efficiently inhibit melanogenesis. The inhibitory effect of GCG was best, followed by ECG, EGCG, and arbutin in turn.