Evaluation of the photoprotective potential of new marine origin UV-filters: study of the photostability, phototoxicity, allergenic potential and performance

Abstract

Marine natural compounds have often been used in sunscreens due to their antioxidant and biological filter activities. Among these substances, mycosporine-like aminoacids are remarkable for their UV filter properties and some analogs have already been used in sunscreens. However, there are not many studies evaluating the photorreactivity and photosensitization of agae metabolites and these kinds of studies as well as the evaluation of UV absorption are extremely important for the evaluation of a new UV filter candidate. Thus, the aim of the present study is to evaluate the photoprotective potential of new marine origin UV-filters through photostability, phototoxicity, allergenic potential and performance studies of sunscreen formulations containing new synthetic substances based on mycophenolic acid, which was obtained from endophytic fungi of red algal Bostrychia radicans. For this purpose, firstly more mycophenolic acid will be obtained from the extracts of Phomopsis longicolla and Penicillium brevicompactum. After that, new synthetic analogues based on mycophenolic acid will be prepared from reactions with caffeic and cinnamic acids in order to promote molecular weight enhancement, reduction of polarity, enhancement of UVA absorption and some other structural modifications on mycophenolic acid. The synthetic analogues will be submitted to the evaluation of UV absorption spectra and photodegradation. Phototoxicity will be evaluated by using 3T3 monolayer fibroblast culture to determine cell viability in the presence and absence of UVA radiation. Non-phototoxic substances will be tested by peptide depletion assays (GSH, cysteine and lysine), to predict the allergenic potential of chemicals. Then, the performance of three substances with higher photoprotective potential will be evaluated when added to cosmetic formulations through the evaluation of stability, photostability and in vitro cutaneous penetration studies as well as through the in vivo efficacy studies, where the analysis of clinical and histological alterations, such as apoptosis markers, on hairless mouse skin submitted to UV radiation, will be performed. (AU)