欧前胡素抑制人表皮黑素细胞黑素生成

目的：评价欧前胡素对培养人表皮黑素细胞黑素生成的作用。方法：体外分离、纯化培养人表皮黑素细胞。随机分为空白组、熊果苷组和欧前胡素组（12．5μM，25μM和50μM），作用48h，观察黑素细胞形态．检测黑素细胞活力、酪氨酸酶活性和黑素含量，免疫荧光显微镜观察欧前胡素对黑素细胞酪氨酸酶的影响。结果：不同浓度（0、12．5μM、25μM和50μM）欧前胡素作用于黑素细胞48h后，细胞活力分别为100％、107．8％、87．5％和59．7％。低浓度欧前胡素不影响黑素细胞形态,高浓度（50μM）对黑素细胞活力、酪氨酸酶活性、黑素含量有抑制作用，呈剂量依赖性。欧前胡素对酪氨酸酶蛋白在细胞内定位未见明显影响，但酪氨酸酶荧光强度降低。结论：欧前胡素抑制体外培养人表皮黑素细胞酪氨酸酶活性而降低黑素生成。

Inhibitory effects of imperatorin on melanogenesis of human epidermal melanocytes in vitro

Objective： To investigate the effects of imperatorin on cultured human epidermal melanocytes. Methods： Human epidermal melanocytes were separated and cultured in vitro. Melanocytes were randomly di- vided into control group, arbutin group and imperatorin group（ 12.5 μM, 25 μM, 50 μM）. After 48 h incuba- tion, the effects of morphology of melanocytes were observed under microscopy. The cell viability, tyrosinase activity and melanogenesis in cultured human epidermal melanocytes were measured. The effect of imperatorin on distribution of tyrosinase in melanocytes was observed by immunofluorescence method. Results： Our study showed that when different concentrations （0, 12.5 μM, 25 μM, 50 μM） of imperatorin were administered to melanocytes for 48 h, the cell vitality were 100%, 107.8%, 87.5% and 59.7% respectively. Imperatorin had no significant effect on cellular morphology but slightly increased viability of melanocytes at low dosages （ 12.5 - 25 μM）, and it inhibited cellular viability, tyrosinase activity and melanogenesis at 50 μM level. The inhibitory effects of imperatorin were in a concentration-dependent manner. Immunofluorescence microscopy showed that the location of tyrosinase in melanocytes was not obviously changed, but the fluorescence intensity of tyrosinase attenuated. Conclusion： Imperatorin can reduce melanogenesis by inhibiting tyrosinase activity in cultured human epidermal melanocytes.