Avaliação in vitro da atividade fotoprotetora de extratos vegetais do cerrado de Mato Grosso

Abstract

RESUMO:O cerrado brasileiro é um bioma detentor de grande diversidade biológica. No entanto, são escassas as pesquisas de espécies vegetais, especialmente do cerrado mato-grossense, com potencial para serem utilizadas como filtros solares naturais. O objetivo desta pesquisa foi estudar o potencial fotoprotetor de espécies de diferentes famílias (Apocynaceae, Lythraceae, Oxalidaceae) do cerrado da região do Rio Manso, Chapada dos Guimarães -MT. A absorbância dos extratos etanólicos secos foram medidas em diferentes concentrações entre os comprimentos de onda de 260 a 400nm para verificar a absorção nas regiões ultravioleta A e B (UVA e UVB). As plantas que apresentaram absorbância na região estudada foram submetidas a uma análise fitoquímica qualitativa preliminar para determinar a presença de polifenóis e alcalóides, constituintes característicos de plantas que absorvem a radiação UV. Os extratos etanólicos secos que apresentaram absorção em UVB foram submetidos ao teste de determinação in vitro do Fator de Proteção Solar (FPS) desenvolvido por Mansur. M. Velame apresentou absorção na região UVB com absorbância máxima em 318nm, enquanto que a L. pacari e O. hirsutissima apresentaram absorbância na região UVA. Na concentração utilizada e padronizada, nenhuma das espécies apresentou FPS ≥2, sendo assim não podem ser consideradas plantas com potencial fotoprotetor.Unitermos: Apocynaceae, atividade fotoprotetora, Cerrado de Mato Grosso, fator de proteção solar in vitro, Lythraceae, Oxalidaceae.ABSTRACT: "In vitro sunscreen activity evaluation of plants extracts from Mato Grosso cerrado". The Brazilian savanna is a holding biome of large biological diversity. However, the researches of plants species are scarce, especially at the Mato Grosso´s savanna; which have potential to be used as natural sunscreen. The objective of this research was to study the photoprotector potential of several species (Apocynaceae, Lythraceae, Oxalidaceae) from the savanna´s region at the Manso River, Chapada dos Guimarães -MT. The absorbance of dry ethanolic extracts were measured in different concentrations, between waves from 260nm until 400 nm in length. Just to check the absorption in the A and B ultraviolet regions (UVA and UVB). The plants that presented absorbance by the studied area were submitted to a preliminary qualitative phytochemical analysis to determine if there are polyphenols and alkaloids inside, because they are typical constituents of plants that absorber the UV radiation. The dry ethanolic extracts, that presented absorption in UVB, were submitted to a in vitro Sun Protection Factor (SPF) determination test, developed by Mansur. M.velame presented absorption in the UVB region with maximal absorbance at 318 nm, while L. pacari and O. hirsutissima presented absorbance in the UVA region. At the used and standardized concentration, no species presented SPF ≥ 2, so they cannot be considered plants with photoprotector potential.

Development of O/W emulsions containing Euterpe oleracea extract and evaluation of photoprotective efficacy

“…The SPF results obtained in our experimental study are consistent with findings reports in previous studies (Silva et al, 2005;Souza et al, 2005;Lopes et al, 2007;Violante et al, 2009;Ferrari, Rocha-Filho, 2011;Mansur et al, 2012). The cited studies described the difficulty in increase in the SPF value by the addition of natural active agents in the formulation containing chemical and/or physical UV filters.…”

“…Given the structural similarities between polyphenolic compounds and organic UV filters, in addition to the antioxidant activity of these bioactive compounds, they might exert photoprotective activity (Velasco et al, 2008a;Velasco et al, 2008b;Violante et al, 2009).…”

Phytochemical analysis and evaluation of antioxidant and photoprotective activities of extracts from flowers ofBromelia laciniosa(Bromeliaceae)

“…Subsequently, spectrophotometric scanning was performed at wavelengths between 260 and 400 nm, with intervals of 5 nm. The readings were carried out using a 1-cm quartz cell, and ethanol was used as blank [20]. Calculation of sun protection factor (SPF) was obtained according to the equation developed by Mansur et al [21]:…”

Development of Broad-Spectrum Natural Sunscreens using Combinations of five Plant Species

“…For those subject to analysis, the values exceeded the amounts normally found in the literature. [16][17][18][19] According to Cabral et al, 20 natural sunscreens presented considerably low absorption, so the use of plant extracts is recommended as adjuncts to the synthetic filters. Thus, the innovative product was surprising since it met the goal of developing a different naturally occurring product that provides skin protection, contributing to consumer acceptance.…”