Photostabilization of sunscreens by incorporation of tea as the external phase

Abstract

The use of isolated ultraviolet (UV) filters in photoprotective formulations creates products with limited protection against radiation, emphasising the need to develop formulations containing UVA and UVB filter combinations. However, most of the formulations developed to include both filters are unstable as a result of this combination, as well as by exposure to UV radiation. It is, therefore, crucial to include additives that enable photostabilization. Tea is the second most widely consumed beverage in the world and represents a good source of bioactive compounds, particularly polyphenols, which provide antioxidant activity. In the present work formulations containing green tea or black tea, as well as the sunscreens avobenzone (UVA sunscreen) and octilmetoxinamato (UVB sunscreen), were developed and evaluated in order to develop new and effective photostable formulations providing broad spectrum photoprotection. These formulations have been developed with complete replacement of the external phase of the oil in water (O/W) emulsion by these teas. The results showed that both teas presented photostabilizing capacity, particularly for green tea in the storage conditions at room temperature and at 5 °C, and black tea for the samples stored at 40 °C. Key-words: green tea, black tea, photoprotective formulations, photostabilizing capacity, octyl methoxynnamate, avobenzone