Estudo fitoquímico de Psidium guineense SW. (Araçá) e avaliação da sua atividade antioxidante e fator de proteção solar

Abstract

For centuries, plants have been one of the main sources of resources for humanity. Unimaginable source of substances thanks to its primary and secondary metabolism, which are responsible for the production of a variety of substances. These substances, from natural sources, are increasingly used in the development of technologically prepared bioproducts, with proven efficacy, safety and quality, with application in the most diverse areas and used in the production of lotions, moisturizers, toothpastes, shampoos, sunscreens, etc. Brazil has the greatest biodiversity on the planet, with about 20% of all the world's flora and consisting of great genetic diversity, making it promising for the study and applicability of active substances of natural origin for the development of bioproducts. This research aimed to investigate the chemical constitution of the ethanolic extract of the fruits of Psidium guineense Swartz, isolating and identifying substances present in its fruits, as well as to evaluate the antioxidant potential and the photoprotective capacity of the ethanol extract and its addition in polawax cream, glimpsing a potential use in cosmetic preparations. In the city of Areia, PB, the fruits were collected and at the Federal University of Paraíba (UFPB), Campus II, the fruits were dried, macerated and their ethanolic phase obtained by extraction by maceration. From the ethanol extract, phytochemical screening was performed to prove or deny the presence of important secondary metabolite groups: tannins, saponins, steroids, triterpenes, flavonoids, alkaloids, coumarins and quinones. For this, colorimetric and precipitation reactions were used. Two highlighted substances, obtained as yellow powder, were purified on chromatographic columns. These two substances, Pa-1 and Pa-2, were analyzed by Nuclear Magnetic Resonance (NMR) at 1H and 13C in the Bruker Avance III equipment at 400 MHz and 100 MHz, using the solvent dimethylsulfoxide (DMSO) and acetone, both deuterated. The quantification of total flavonoids was carried out by the spectrophotometric method using the flavonoid rutin as a standard, quantification of the antioxidant activity by the DPPH radical capture method and the photoprotective potential of the ethanol extract was evaluated using the in vitro methodology proposed by Sayer. With the results obtained, it was possible to identify the groups of secondary metabolites present in the ethanolic extract of the Fruto da P. guineense and to isolate two flavonoids, kaempferol and quercetin. As well as quantified the content of total flavonoids, the antioxidant capacity in terms of EC50 and the sun protection factor (SPF) of the pure extract and mixed with polawax cream.