Yokota T, Nishio H, Kubota Y, Mizoguchi M
Basic Research Laboratory, Kanebo, LTD, Odawara, Kanagawa, Japan.
Pigment Cell Res. 1998 Dec;11(6):355-61. doi: 10.1111/j.1600-0749.1998.tb00494.x.
Glabridin is the main ingredient in hydrophobic fraction of licorice extract affecting on skins. In this study, we investigated inhibitory effects of glabridin on melanogenesis and inflammation using cultured B16 murine melanoma cells and guinea pig skins. The results indicated that glabridin inhibits tyrosinase activity of these cells at concentrations of 0.1 to 1.0 microg/ml and had no detectable effect on their DNA synthesis. Combined analysis of SDS-polyacrylamide gel electrophoresis and DOPA staining on the large granule fraction of these cells disclosed that glabridin decreased specifically the activities of T1 and T3 tyrosinase isozymes. It was also shown that UVB-induced pigmentation and erythema in the skins of guinea pigs were inhibited by topical applications of 0.5% glabridin. Anti-inflammatory effects of glabridin in vitro were also shown by its inhibition of superoxide anion productions and cyclooxygenase activities. These data indicated that glabridin is a unique compound possessing more than one function; not only the inhibition of melanogenesis but also the inhibition of inflammation in the skins. By replacing each of hydroxyl groups of glabridin with others, it was revealed that the inhibitory effect of 2'-O-ethyl glabridin was significantly stronger than that of 4'-O-ethyl-glabridin on melanin synthesis in cultured B16 cells at the concentration of 1.0 mg/ml. With replacement of both of two hydroxyl groups, the inhibitory effect was totally lost. Based on these data, we concluded that two hydroxyl groups of glabridin are important for the inhibition of melanin synthesis and that the hydroxyl group at the 4' position of this compound is more closely related to melanin synthesis.
光甘草定是甘草提取物中影响皮肤的疏水部分的主要成分。在本研究中，我们使用培养的B16小鼠黑色素瘤细胞和豚鼠皮肤研究了光甘草定对黑色素生成和炎症的抑制作用。结果表明，光甘草定在0.1至1.0微克/毫升的浓度下可抑制这些细胞的酪氨酸酶活性，并且对其DNA合成没有可检测到的影响。对这些细胞的大颗粒部分进行SDS-聚丙烯酰胺凝胶电泳和多巴染色的联合分析表明，光甘草定特异性地降低了T1和T3酪氨酸酶同工酶的活性。还表明，局部应用0.5%的光甘草定可抑制豚鼠皮肤中紫外线B诱导的色素沉着和红斑。光甘草定在体外的抗炎作用还通过其对超氧阴离子产生和环氧化酶活性的抑制作用得以体现。这些数据表明，光甘草定是一种具有多种功能的独特化合物；不仅抑制黑色素生成，还抑制皮肤炎症。通过用光甘草定的每个羟基替换为其他基团，发现在1.0毫克/毫升的浓度下，2'-O-乙基光甘草定对培养的B16细胞中黑色素合成的抑制作用明显强于4'-O-乙基光甘草定。当两个羟基都被替换时，抑制作用完全丧失。基于这些数据，我们得出结论，光甘草定的两个羟基对于抑制黑色素合成很重要，并且该化合物4'位的羟基与黑色素合成关系更密切。
