中药桂枝抑制黑素生成的作用机理研究

Down-regulation of Melanin Synthesis by Ramulus Cinnamomi and its Mechanism

目的研究中药桂枝对小鼠黑素细胞系M el-a黑素生成、酪氨酸酶活性及基因表达的影响,阐明桂枝抑制黑素生成的机理。方法用药物处理M el-a细胞后进行黑素含量、L-DOPA染色、放免法测定酪氨酸酶活性,western b lot和实时RT-PCR分别测酪氨酸酶及酪氨酸酶相关蛋白的蛋白和mRNA表达水平。选取熊果苷作为阳性对照。结果10μg/m l浓度的桂枝提取物在细胞培养水平对黑素生成有明显地抑制作用,强于20μg/m l浓度的熊果苷。桂枝可以抑制酪氨酸酶mRNA表达;减少这种限速酶的蛋白产量,在细胞量相同的情况下,桂枝明显抑制酪氨酸酶的氧化活性。结论中药桂枝有很强的抑制黑素产生的作用,其作用是通过抑制酪氨酸酶的基因表达、蛋白合成和氧化活性这三方面来实现。

Objective To investigate the effects of Ramulus Cinnamomi extracts on melanogenesis of mel-a cells,including the content of melanin,the activity and content of tyrosinase and other tyrosinase related proteins, Methods Melanin content was measured using NaOH assay. L-DOPA staining and isotope assay were used to measure the activity of tyrosinase, Western blot and real-time RT-PCR were used to measure the protein content and mRNA level of tyrosinase and related proteins, Arbutin was used as positive control, Results 10μg/ml Ramulus Cinnamomi extracts could down regulate the melanin synthesis, and was more effective than that of 20 μg/ml arbutin, The Ramulus Cinnamomi extracts could inhibit the mRNA expression and protein translation of tyrosinase,and inhibit the activity of tyrosinase. Conclusion The Ramulus Cinnamomi extracts can strongly inhibit the melanin synthesis;the mechanism of its effect is via inhibiting of the mRNA expression,protein translation and activity of tyrosinase.