Avaliação das atividades antioxidante e fotoprotetora in vitro de partições do extrato metanólico de Mitracarpus frigidus (Rubiaceae)

Introduction: The excessive exposure to solar light can cause skin lesions, mainly due to ultraviolet (UVs) rays. The incidence of skin lesions may be reduced by the use of sunscreens. In the last years, several researches were reported based on the investigation of the antioxidant and photoprotective potential of different plant species. Objective: The study aimed to evaluate in vitro antioxidant and photoprotective potential of hexane partition (PHC), dichloromethane partition (PDC), ethyl acetate partition (PAC) and hydroalcoholic partition (PAGC) of methanolic extract from Mitracarpus frigidus (Willd. ex Reem Schult.) K. Schum. (Rubiaceae) aerial parts. Material and Methods: The methanolic extract of M. frigidus (MFM) was submitted to a liquid-liquid partition from the solvents hexane, dichloromethane, and ethyl acetate, remaining a hydroalcoholic partition at the end of the process. Then, the total flavonoid content was dosed and the antioxidant and photoprotective capacity of the partitions were evaluated based on DPPH test: free radical scavenging method, method of reducing the phosphomolybdenum complex, assay of the b-carotene/linoleic acid system; determination of the Sun Protection Factor (SPF) and the UVA, UVB and UVC absorption spectra. Results: Only the ACP was promising for antioxidant (IC50 2.15 ± 0.20 µg/mL; %RAA 312 ± 25.59 e 120 ± 9.85 compared to rutin and quercetin, respectively, and %I 70.31 ± 0.48) and photoprotective (SPF 12.11 ± 0.02) activities, it might be due to the great content of flavonoid compounds found in the sample (336.91 ± 1.89 mg/g). Conclusion: The search for natural products with biological activity has become a worldwide trend. Therefore, it is possible to affirm that the ACP can act as an adjuvant in sunscreens.