Faculdade de Ciências Farmacêuticas de Ribeirão Preto, University of São Paulo, São Paulo, Brazil.
Skin Pharmacol Physiol. 2009;22(6):299-304. doi: 10.1159/000241299. Epub 2009 Sep 25.
Green tea (Camellia sinensis) and Ginkgo biloba extracts in cosmetic formulations have been suggested to protect the skin against UV-induced damage and skin ageing. Thus, it is very important to assess the human skin penetration of their major flavonoids to verify if they penetrate and remain in the skin to exert their proposed effects. The aim of this study was to evaluate the human skin penetration of epigallocatechin-3-gallate (EGCG) and quercetin from green tea and G. biloba extracts vehiculated in cosmetic formulations. This study was conducted with fresh dermatomed human Caucasian skin from abdominal surgery mounted on static Franz diffusion cells. Skin samples were mounted between two diffusion half-cells and 10 mg/cm(2) of formulations supplemented with 6% of green tea or G. biloba extract were applied on the skin surface. The receptor fluid was removed after 6 and 24 h and analyzed by high-performance liquid chromatography for the quantification of the flavonoids. The stratum corneum was removed by tape stripping and immersed in methanol and the epidermis was mechanically separated from the dermis and triturated in methanol to extract EGCG and quercetin. The results showed that the flavonoids under study penetrated into the skin, without reaching the receptor fluid. The majority of EGCG was quantified in the stratum corneum (0.87 microg/cm(2)), which was statistically higher than the EGCG concentrations found in viable epidermis (0.54 microg/cm(2)) and in the dermis (0.38 microg/cm(2)). The majority of quercetin was quantified in the viable epidermis (0.23 microg/cm(2)), which was statistically higher than the EGCG concentration found in the stratum corneum layer (0.17 microg/cm(2)). Finally, it can be concluded that EGCG and quercetin from green tea and G. biloba extracts vehiculated in cosmetic formulations presented good skin penetration and retention, which can favor their skin effects.
绿茶（Camellia sinensis）和银杏叶提取物在化妆品配方中被认为可以保护皮肤免受紫外线引起的损伤和皮肤老化。因此，评估其主要类黄酮在人体皮肤中的渗透情况非常重要，以验证它们是否渗透并留在皮肤中发挥其预期作用。本研究旨在评估绿茶和银杏叶提取物中表没食子儿茶素-3-没食子酸酯（EGCG）和槲皮素在载于化妆品配方中的透皮情况。本研究使用来自腹部手术的新鲜去皮人体白种人皮肤，将其安装在静态 Franz 扩散细胞上。将 10mg/cm(2)补充有 6%绿茶或银杏叶提取物的制剂应用于皮肤表面，在皮肤表面上。在 6 和 24 小时后去除受体液，并通过高效液相色谱法分析黄酮类化合物的含量。通过胶带剥离去除角质层，并用甲醇浸泡，将表皮从真皮中机械分离并在甲醇中捣碎以提取 EGCG 和槲皮素。结果表明，所研究的类黄酮渗透到皮肤中，但未到达受体液。大部分 EGCG 定量在角质层（0.87μg/cm(2)）中，明显高于活表皮（0.54μg/cm(2)）和真皮（0.38μg/cm(2)）中的 EGCG 浓度。大部分槲皮素定量在活表皮（0.23μg/cm(2)）中，明显高于角质层（0.17μg/cm(2)）中的 EGCG 浓度。最后，可以得出结论，载于化妆品配方中的绿茶和银杏叶提取物中的 EGCG 和槲皮素具有良好的皮肤渗透性和保留性，这有利于它们的皮肤效果。
