Department of Pharmaceutical Technology and Center of Excellence for Innovation in Chemistry, Naresuan University, Thailand.
Int J Cosmet Sci. 2011 Dec;33(6):572-9. doi: 10.1111/j.1468-2494.2011.00673.x. Epub 2011 Jul 25.
Catechins are major antioxidants in green tea (Camellia sinensis or Camellia assamica), but because they do not permeate the skin well, the application of green tea in cosmetic products has so far been limited. This study aims to evaluate the cutaneous absorption of catechins from an extract of green tea and from a green tea extract-loaded chitosan microparticle. The catechin skin metabolism was also examined. The results suggest that chitosan microparticles significantly improve the ability of catechins to permeate skin. The cutaneous metabolism of the catechins significantly affected their permeation profiles. Epicatechin (EC) and epigallocatechin (EGC) penetrated the skin more than epigallocatechin gallate (EGCG) and epicatechin gallate (ECG). The galloyl groups in EGCG and ECG were enzymatically hydrolysed to EGC and EC, respectively. Dehydroxylation of catechins was also observed. Chitosan microparticles effectively prevented enzymatic changes of the catechins; therefore, chitosan microparticles are here found to be the promising carriers for enhancing the skin permeation.
儿茶素是绿茶（Camellia sinensis 或 Camellia assamica）中的主要抗氧化剂，但由于它们不易穿透皮肤，因此迄今为止，绿茶在化妆品中的应用一直受到限制。本研究旨在评估从绿茶提取物和负载绿茶提取物的壳聚糖微球中儿茶素的皮肤吸收情况。还检查了儿茶素的皮肤代谢情况。结果表明，壳聚糖微球显著提高了儿茶素穿透皮肤的能力。儿茶素的皮肤代谢显著影响了它们的渗透特性。表儿茶素（EC）和表没食子儿茶素（EGC）比表没食子儿茶素没食子酸酯（EGCG）和表儿茶素没食子酸酯（ECG）更容易穿透皮肤。EGCG 和 ECG 中的没食子酰基在酶的作用下水解成 EGC 和 EC。儿茶素也发生了去羟基化反应。壳聚糖微球能有效防止儿茶素的酶促变化；因此，壳聚糖微球被发现是增强皮肤渗透的有前途的载体。
