Protective effects of (-)-epicatechin-3-gallate on UVA-induced damage in HaCaT keratinocytes
Protective effects of (-)-epicatechin-3-gallate on UVA-induced damage in HaCaT keratinocytes
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DOI：
10.1007/s00403-005-0540-5
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发表时间：
2005-04-01
影响因子：
3
通讯作者：
Hung, CF
中科院分区：
文献类型：
--
作者：
Huang, CC;Fang, JY;Hung, CF
(-)-表没食子儿茶素-3-没食子酸酯（EGCG）是绿色茶的一种成分，已被广泛研究，并被证明是一种强大的抗氧化剂，保护皮肤细胞免受光损伤。然而，在这项研究中，我们证明了另一种没食子儿茶素，（-）-表儿茶素-3-没食子酸酯（ECG），也能够保护人类角质形成细胞免受紫外线A（UVA）光诱导的损伤。我们发现ECG剂量依赖性地抑制UVA诱导的角质形成细胞死亡，细胞活力测定。此外，ECG在抑制UVA诱导的细胞死亡方面具有与EGCG相似的效力。因此，进一步研究ECG的作用机制。通过流式细胞仪检测，UVA诱导的过氧化氢（H2 O2）在角质形成细胞中的产生被ECG以浓度依赖的方式抑制，这表明ECG可以作为一种自由基清除剂，而角质形成细胞的光损伤。ECG的清除作用通过ECG处理减轻H2 O2和次黄嘌呤-黄嘌呤氧化酶引起的细胞损伤来证实。在平行实验中，UVA诱导的角质形成细胞细胞外信号调节激酶的激活被ECG阻断。我们在这里提供的第一个证据表明，心电图是一种有效的保护剂，保护角质形成细胞免受光损伤。由于心电图是丰富的绿色茶，我们认为，这种化合物是有益的皮肤护理。
(-)- Epigallocatechin-3-gallate (EGCG), a constituent of green tea, has been extensively studied and shown to be a powerful antioxidant protecting skin cells against photodamage. In this study, however, we demonstrated that another gallated catechin, (-)-epicatechin-3- gallate ( ECG), was also able to protect human keratinocytes against damage induced by ultraviolet A (UVA) light. We found that ECG dose-dependently inhibited UVA-induced keratinocyte death as determined by cell viability assay. Moreover, ECG had similar potency to EGCG in inhibiting UVA-induced cell death. Therefore, the mechanism of action of ECG was further investigated. As assayed by flow cytometry, UVA-induced hydrogen peroxide (H2O2) production in keratinocytes was inhibited by ECG in a concentration-dependent manner, suggesting that ECG can act as a free radical scavenger while keratinocytes were photodamaged. The scavenging effect of ECG was confirmed by the fact that ECG treatment attenuated cell damage induced by H2O2 and hypoxanthine-xanthine oxidase. In a parallel experiment, UVA-induced activation of extracellular signal-regulated kinase in keratinocytes was blocked by ECG. We provided here the first evidence that ECG is a potent protectant that protects keratinocytes from photodamage. Because ECG is abundant in green tea, we believe that this compound is beneficial for skin care.