In Vitro Effect Of Piperine On The Growth And Migration Of Cultured Human Melanocytes

Background Piperine is the major alkaloid of Chinese black pepper and piper longum. Donata et al had used piper nigrum fruit orally with other Ayurvedic herbs to treat the patients with vitiligo and showed a positive response. The No.2TCMHs (Chinese black pepper and Glossy privet fruit were the most important component) in our hospital was used to treat vitiligo in the external way, which obtained a better efficacy. The previous study found that piper nigrum fruit and piperine could promote the growth and melanogenesis in melanoma cells and stimulate tyrosinase activity both within and without the cells. In the test of melanocytes, piper nigrum fruit and piperine could stimulate the proliferation and differentiation of melanocytes and stimulate melanogenesis by upregulating the expression of tyrosinase and TRP1. In the latest study: a sparsely pigmented mouse model was used to evaluate the effectiveness of piperine and synthetic analogues as potential treatments for vitiligo, They had got the conclusion that treatment with PIP,THP or rCHP and UVR induced a marked pigmentation response in HRA/Skin-II mice, which got better result clinically than UVR alone. This result supports that the potential use of these compounds in treating vitiligo. The current mechanism of using piperine to treat vitiligo is not yet clear and has no reports about the study of migration of the epidermal melanocytes. To further explore the possible mechanism, we observed the effect of piperine on the growth and migration of the cultured human melanocytes, so that the experimental basis will be provided for developing more safe and effective new drugs to treat vitiligo.Objective To study the effect of piperine, a natural chemical, on the proliferation, tyrosinase activity, melanogenesis and migration of the cultured human melanocytes.Methods The melanocytes were incubated with six different concentrations of natural piperine for 72h. Then cellular proliferation, tyrosinase activity, melanin content of the cells were measured. Meanwhile, the melanocytes were incubated with 6.25ug/ml of natural piperine for 48h, scratch methods and transwell assays were performed to observe the effect of piperine on the migration of melanocytes.Result At a range of 6.25～12.5ug/ml, piperine was found to promote melanocytes proliferation (P<0.05), which was most obvious at the concentration of 6.25 ug/ml (P<0.01). When the concentration was increased to 50ug/ml, the effect of melanocytes proliferation was inhibited (P<0.01). At a range of 25～50ug/ml, piperine was found to promote tyrosinase activity significantly (P<0.01). At a range of 3.125～50ug/ml, piperine was found to stimulate melanogenesis significantly, which was most obvious at the concentration of 12.5ug/ml . However, piperine had little effect on migration of the cultured human melanocyte.Conclusion piperine has a significant stimulatory effect on the proliferation, tyrosinase activity and melanogenesis of the cultured human melanocytes. But has little effect on melanocytes migration.