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SOUZA, R. O. In vitro and in vivo evaluation of photochemoprotective activity of Byrsonima crassifolia fraction and (+) catechin against the damages induced by UVB radiation. 2015. 140f. Thesis (Doctoral) Pharmaceutical Sciences School, University of São Paulo, 2015.Faculdade de CiênciasFarmacêuticas, Universidade de São Paulo, 2015. The skin is the largest tissue of the human body and it is constantly exposed to several harmful agents, such as the ultraviolet radiation (UVR), which is related to the DNA photodamage, generation of reactive oxygen species (ROS) and activation of inflammatory mediators. In these circumstances, even having an antioxidant defense system, the skin is exposed to oxidative stress due to the increase of free radicals concentration, which changes the pro oxidant / antioxidant equilibrium. In this context, natural substances have frequently been employed as a tool to improve the skin ́s endogenous protective system, which ultimately decreases the oxidative damage caused by UVR on the skin. Therefore, this study aimed to evaluate in vitro and in vivo photochemoprotective effect of Byrsonima crassifolia (BC) fraction and (+) catechin (CAT) in human keratinocytes culture and hairless mouse against UVB radiation. If compared to the extract, BC fraction showed higher in vitro antioxidant activity and higher total polyphenols content and phenolic compounds: (+) catechin (255 ± 3.2 mg / g fraction), () epigallocatechin-3-gallate (26 ± 1.68 mg / g of fraction) and quercetin 3O-β-D-glucopyranoside (12 ± 0.09 mg / g of fraction). The gel formulation containing to the BC fraction (1%) provided higher release of phenolic compounds on pig ear skin than the emulgel formulation. It was demonstrated that CAT was the major phenolic compound quantified in the viable epidermis (21.72 ± 5,2μg / cm).Thus, BC fraction or CAT were incorporated the gel formulation (1%) and in vivo skin penetration was evaluated. On the viable epidermis of mice hairless it was detected the phenolic compounds of the BC fraction, as well as CAT compound. Photochemoprotector evaluation in keratinocytes cell culture showed that both BC fraction and CAT were able to inhibit lipid peroxidation and to decrease the secretion of IL-6 and NFκB / p65 transcription in the cytoplasm. Regarding the in vivo functional activity, BC fraction and CAT were able to prevent/reduce the depletion of GSH levels, the inflammatory infiltrate and IL-1β and IL-6 secretion induced by UVB radiation. On the other hand, only the BC fraction was able to inhibit the activity/secretion of matrix metalloproteinase MMP-9, which illustrate its strong photochemoprotector activity and suggests that the plant fraction effect can be superior to the standard. It can be explained by the fact that the fraction is a complex sample in which several substances are present and these substances can enhance the polyphenol activity. These results are promising and suggest the use of BC fraction and CAT in the prevention/treatment of the damages induced by UVB radiation in the skin.

Avaliação in vitro e in vivo da atividade fotoquimioprotetora da fração de Byrsonima crassifolia e da (+)-catequina contra os danos induzidos pela radiação UVB