Herbal sun protection agents: Human studies

Topical sunscreens are the mainstay for protection from ultraviolet (UV) radiation. With skin cancer rates on the rise and great interest in reversing or preventing the effects of photoaging, new molecules with potential to defend against UV damage have received a great deal of attention. Specifically, there is a growing interest in herbal substances that offer protection against the damaging effects of UV rays. Herbal substances may work as adsorbents of the UV rays and antioxidants and potentially have few side effects. Many of them have shown the potential to protect from UV rays in in vitro studies and animal models; however, only a limited number of human studies were conducted which we discuss in the current review. Among the most studied herbal substances that have proven photoprotective activity are green tea extract, carotenoids, and Polypodium leucotomos extract (PLE). They have been shown to increase minimal erythema dose and improve signs of photodamage. PLE has been shown to be helpful in holistic treatment of several conditions, including polymorphous light eruption, solar urticaria, and melasma; it also may be used as an adjuvant to the UVB treatment of vitiligo and photodynamic therapy of actinic keratosis.