Katiyar et al. have published a review on green tea polyphenolic antioxidants and skin photoprotection.1 Green tea is consumed as a popular beverage worldwide, particularly in Asian countries such as China, Korea, Japan and India, and it contains polyphenolic compounds known as epicatechins, which are antioxidant in nature. Many laboratories have shown that topical treatment or oral consumption of green tea polyphenols inhibits chemical carcinogens or UV radiationinduced skin tumorigenesis in different animal models. Studies have shown that green tea extract also possesses anti-inflammatory activity. These anti-inflammatory and anti-carcinogenic properties of green tea are due to the polyphenolic constituents present therein. The major and most chemopreventive constituent in green tea responsible for these biochemical or pharmacological effects is (-)-epigallocatechin-3-gallate (EGCG).
Understanding the molecular mechanisms of green tea effects is a subject of investigation in many laboratories. Using green tea polyphenols in skin treatments has been shown to modulate the biochemical pathways involved in inflammatory responses, cell proliferation and responses of chemical tumor promoters as well as UV light-induced inflammatory markers of skin inflammation. Topical treatment with EGCG on mouse skin also results in prevention of UV B-induced immunosuppression and oxidative stress. The protective effects of green tea, either through topical treatment or oral consumption, against UV light-induced inflammatory or carcinogenic responses in human skin are not well understood. Based on beneficial effects of green tea on skin, which has been documented extensively using mouse models and a few human skin studies, many pharmaceutical and cosmetic companies are supplementing their skin care products with green tea extracts. Therefore, the focus of this communication is to review and analyze the photoprotective effects of green tea polyphenols on skin.
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