桑白皮多酚对B16细胞内黑色素生成的影响及其机制

摘要

Aim To investigate the inhibitory effect of polyphenol from Cortex Mori( CMP) on melanogenesis in mouse melanoma B16 cells and its possible mecha- nism. Methods Melanoma B16 cells with high ex-pression melanin were induced by α-melanocyte-stimu-lating hormone ( α-MSH) to establish cell model. Cell viability was detected by MTT assay. The melanin syn-thesis and tyrosinase activity were measured by NaOH and L-Dopa assays, respectively. The tyrosinase (TYR), tyrosinase-related protein-1 (TRP-1), tyrosi-nase-related protein-2 ( TRP-2 ) and microphthalmia associated transcription factor ( MITF ) protein and mRNA levels were measured by Western blot and qRT-PCR, respectively. Results CMP could inhibit the melanin synthesis and tyrosinase activity in α-MSH stimulated B16 cells in a dose-dependent manner ( P<0.05) . The melanin content and tyrosinase activity significantly decreased by 52.95% , 32.85% at 20 mg ·L-1of CMP, respectively. Treatment of 100 mg· L-1of arbutin reduced the melanin content and tyrosi- nase activity by 17.29% , 16.75% , respectively. Based on the results of this study, CMP showed a stronger anti-melanogenesis activity than that of positive control arbutin. After treated by CMP, the protein and mRNA levels of TYR, TRP-1, TRP-2 and MITF were significantly inhibited compared to the α-MSH group ( P<0.05) . Conclusions CMP could suppress the melanogenesis in α-MSH stimulated B16 cells, and its mechanism may be related to its regulation of the pro-tein and mRNA expressions of TYR, TRP-1, TRP-2 and MITF, and the inhibition of tyrosinase activity.%目的 研究桑白皮多酚( polyphenol from Cortex Mori, CMP)对小鼠B16细胞内黑色素生成的影响,并探究其作用机制.方法 体外培养小鼠B16 细胞,构建α-黑素细胞刺激素( α-MSH)诱导的黑色素高表达细胞模型. CMP 干预B16细胞,MTT法测定细胞活性;分别利用NaOH裂解法和L-Dopa氧化法,分析细胞内黑色素生成含量和酪氨酸酶活性的变化;Western blot 和实时荧光定量 PCR 法分别测定B16细胞中酪氨酸酶(TYR)、酪氨酸酶相关蛋白-1(TRP-1)、酪氨酸酶相关蛋白-2(TRP-2)、小眼畸形相关转录因子(MITF)的蛋白质和mRNA水平.结果 CMP对α-MSH诱导的B16细胞内黑色素生成及酪氨酸酶活力均具有明显的抑制作用(P<0.05),且呈量效关系.当CMP浓度为20 mg ·L-1时,对细胞内黑色素生成及酪氨酸酶活性抑制率分别为52.95% 、32.85% ,阳性对照熊果苷(100 mg·L-1)的抑制率分别为17.29% 、16.75% ,表明CMP对黑色素生成的抑制效果强于熊果苷.与α-MSH模型组相比,CMP干预后细胞内TYR、TRP-1、TRP-2、MITF的mRNA和蛋白表达被明显抑制(P<0.05).结论 CMP明显抑制α-MSH诱导黑色素的生成,其机制可能是通过调控 TYR、TRP-1、TRP-2、MITF mRNA和蛋白表达,进而抑制酪氨酸酶活性实现的.