摘要
目的 探讨积雪草甙外用脱色素的作用机制。方法 体外观察积雪草甙对蘑菇酪氨酸酶活性的作用并进行酶促反应动力学分析。进一步以系列浓度的积雪草甙作用于体外培养的Cloudman 591黑素瘤细胞,测定细胞酪氨酸酶活性、黑素含量和细胞增殖率。结果 积雪草甙能剂量依赖性抑制蘑菇酪氨酸酶活性,酶促动力学分析提示积雪草甙为蘑菇酪氨酸酶混合型抑制剂。进一步研究发现,积雪草甙能抑制体外培养的Cloudman S91黑素瘤细胞酪氨酸酶活性和黑素合成,但对细胞增殖无明显影响。与氢醌相比,积雪草甙抑制酪氨酸酶活性低于相同浓度的氢醌。结论 积雪草甙可直接作用于黑素细胞,抑制黑素合成,是一种无细胞毒性的皮肤脱色剂。
Objective Clinical studies have demonstrated that topical asiaticoside improves hyperpigmented lesions of epidermal hypermelanoses such as melasma and freckles, etc. The basic mechanisms underlying this effects of asiaticoside are not known. In this study, we studied the effects of asiaticoside on the activity of mushroom tyrosinase and melanogenesis in Cloudman S91 melanoma cells to elucidate this problem. Methods The effects of asiaticoside on the L-dopa oxidase of mushroom tyrosinase was analysed in a cell-free system, were incubated with Cloudman S91 melanoma cells at serial concentrations for 72 h, and then melanin content and tyrosinase activity were measured. Results We found that asiaticoside had dose-dependent inhibitory effect on the activity of mushroom tyrosinase. showing 44% of inhibition as compared with the control at concentration of 4 μg/mL. According to a kinetic study of tyrosinase with L-dopa as a substrate, asiaticoside is a mixed type inhibitor for the enzyme. Furtherly, we investigated the in vitro effect of asiaticoside on melanogenesis in Cloudman S91 melanoma cells, the results showed that asiaticoside decreased significantly melanogenesis in terms oi tyrosinase activity and melanin synthesis, although had no significant effect on cellular prolifer-ative potential. However, the inhibitor, effects of asiaticoside on melanogenesis was inferior to hydroquinone. Conclusion These results suggested that asiaticoside could be used as a non-cell-toxic whitening agent for the skin.
出处
《中国中西医结合皮肤性病学杂志》
CAS
2004年第1期7-10,共4页
Chinese Journal of Dermatovenereology of Integrated Traditional and Western Medicine
