Development of herbal sunscreen formulations from the leaves of Sri Lankan medicinal plants, <em>Hibiscus furcatus</em> wild. and <em>Olax zeylanica</em> Linn

Abstract

Excessive exposure to ultraviolet (UV) radiation in the sunlight has many deleterious consequences on human skin. In order to alleviate these harmful effects, sunscreen formulations are widely used. Although most of these synthetic sunscreens are highly effective, the adverse effects associated with these products should not be neglected. The current trend, therefore, is to explore natural sources to develop novel sunscreen formulations that are efficacious and more human-friendly. This study was conducted to formulate herbal sunscreens using two Sri Lankan medicinal plants used as remedies for dermatological conditions, <em>hibiscus furcatus </em>wild (nabiriththa) and <em>olax zeylanica </em>linn. (mella) and to evaluate their efficacy. Initially, aqueous-methanolic extracts were prepared from the leaves of the two plants, followed by the preparation of sunscreen formulations from each extract by incorporating different concentrations of the extracts into an aqueous cream base. Thereafter, the uv absorbance and sun protection factor (spf) were obtained. The sunscreen formulations containing 75% of each extract displayed high UV absorbance and the highest spf values. The photostability profiles indicated that some formulations prepared from <em>o. zeyalnica </em>were more effective than the formulations developed from <em>h. furcatus</em>. Therefore, this preliminary study demonstrated the suitability of <em>h. furcatus </em>and <em>o. zeylanica </em>extracts towards the development of commercial herbal sunscreens.