Life Science Research Center, Lion Corporation, Kanagawa, Japan.
Int J Cosmet Sci. 2000 Aug;22(4):291-303. doi: 10.1046/j.1467-2494.2000.00023.x.
The efficacy of ellagic acid (EA), one of the naturally occurring polyphenols, in inhibiting melanogenesis was examined in vitro and in vivo. When mushroom-derived tyrosinase, a metaloprotein containing copper, was incubated with EA, enzymatic activity tended to decrease with decreasing copper concentration. Enzyme activity partially recovered when copper was added to the inactivated enzyme. Tyrosinase activity in the B16 melanoma cells was observed to recover in a dose-dependent manner when copper ions were added to the medium containing EA. Based on these results, EA is thought to react specifically with the copper located at the active centre of the tyrosinase molecule. Furthermore, when EA was applied for 6 weeks to brownish guinea-pigs, which have melanocytes in their skin, at the same time as irradiating for 2 weeks with ultra-violet light, skin pigmentation was clearly suppressed and the skin to which EA had been applied showed features similar to that of non-irradiated skin. These areas were irradiated again when the application of EA had been completed, and skin pigmentation occurred at the former site of EA application. In similar studies with hydroquinone, re-pigmentation did not occur on the sites at which hydroquinone (1%) had been applied. Based on the results reported here, EA is thought to suppress melanogenesis by reacting with activated melanocytes and without injuring cells.
研究了天然多酚之一鞣花酸（EA）在体外和体内抑制黑色素生成的功效。当蘑菇衍生的酪氨酸酶（一种含有铜的金属蛋白酶）与 EA 孵育时，酶活性随着铜浓度的降低而降低。当向失活的酶中添加铜时，酶活性部分恢复。当向含有 EA 的培养基中添加铜离子时，观察到 B16 黑色素瘤细胞中的酪氨酸酶活性呈剂量依赖性恢复。基于这些结果，EA 被认为与位于酪氨酸酶分子活性中心的铜特异性反应。此外，当 EA 在 6 周内应用于皮肤中有黑色素细胞的棕色豚鼠的同时，用紫外线照射 2 周时，皮肤色素沉着明显受到抑制，并且应用 EA 的皮肤显示出与未照射皮肤相似的特征。当 EA 的应用完成后，再次对这些区域进行照射，并且在 EA 应用的先前部位出现皮肤色素沉着。在与对苯二酚的类似研究中，在应用对苯二酚（1%）的部位没有出现再色素沉着。基于这里报道的结果，EA 被认为通过与活化的黑色素细胞反应而不损伤细胞来抑制黑色素生成。
