It is well-known that chronic exposure to ultraviolet light found in sunlight leads to photoaging. Photoaging of the skin refers to the loss of tone, wrinkling, discoloration, increased redness, and the development of skin cancer, even melanoma. There is good evidence that UV radiation induces the production of reactive oxygen species, otherwise known as oxygen free-radicals, which can overwhelm the skin’s natural anti-oxidant defenses. These reactive oxygen species go on to damage proteins, cell membranes, and other macromolecules. The damage to lipids, proteins, and DNA in skin cells can build up over time and become evident as photoaging. The extracellular matrix which contains collagen and elastin also sustains cumulative damage that contributes to photoaging.
Green tea has recently garnered a lot of attention for the antioxidant polyphenols that it contains. Both oral and topical administration of green tea polyphenols in human and mouse experimental models has shown their ability to prevent signs of ultraviolet-induced damage. Green tea has even been shown to inhibit and reverse the formation of skin cancers in mice subjected to ultraviolet photodamage. Topical treatment of human skin with green tea polyphenols has been shown to prevent the DNA damage that leads to skin cancer. Clearly, green tea is a powerful anti-oxidant, and there is good evidence to support its use in the general population to help prevent photoaging and to decrease the risk of skin cancer.
Pomegranate has entered the scene a little more recently but has generated explosive interest. The juice and peels contain powerful antioxidants, anthocyanins, a group of polyphenolic compounds that possess antioxidant and anti-inflammatory properties. In a comparative analysis, anthocyanins from pomegranate fruit were shown to possess higher antioxidant activity than vitamin E (alpha-tocopherol), ascorbic acid, and ß-carotene. Experiments in mouse models have shown that topical pre-treatment with pomegranate polyphenols prevented the molecular signs of ultraviolet-induced photodamage leading to skin cancer. Although green tea polyphenols have a head-start on pomegranate, the amount of research generated by pomegranate in the last 10 years has skyrocketed. More information related to prevention of cancer and cardiovascular disease by pomegranate is likely to be published in the near future.