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Evaluation of the antioxidant and photoprotective activity of Xylopia langsdorffiana St-hill & Tul.
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1  1Postgraduate Program in Natural and Synthetic Bioactive Products, Health Sciences Centre, Federal University of Paraiba, João Pessoa, PB, Brazil


Introduction: The genus Xylopia is widely distributed in Brazil with several species used in folk medicine. Among them, Xylopia langsdorffiana ("peppermint"), which has several secondary metabolites such as alkaloids, diterpenes and flavonoids. In addition, pharmacological studies have already been carried out, demonstrating that this species has cytotoxic, gastroprotective, cicatrizing and spasmolytic activity. However, no studies have been done regarding its antioxidant and photoprotective activities. Objective: In order to contribute to the knowledge of this species, the antioxidant and photoprotective activity of its crude ethanolic extract (CEE) was evaluated. Methods: In order to test antioxidant activity in vitro, the radical scavenging method (DPPH) was used and the results obtained were expressed in EC50. The content of total phenolic compounds was determined using the Folin-Ciocalteu method and to determine the amount of total flavonoids was used the colorimetric method with AlCl3, where all analyzes were done in triplicate. To determine the photoprotective activity, the maximum absorbance technique was used, and it was possible to calculate the sun protection factor (SPF) in vitro. Results: X. langsdorffiana CEE presented EC50 575.01 ± 6.50 μg/mL and did not reach the required minimum value of <500 μg/mL to be considered active. The total phenolic content was 48.34 ± 1.64 mg EAG/g and the flavonoid content of 25.10 ± 2.62 mg querc./g, demonstrating that most of its phenols are flavonoids, and despite obtaining a significant quantity of flavonoids, they may not be related to antioxidant activity. In the evaluation of the photoprotective activity the CEE presented SPF with a value of 2.27 and was considered insufficient to perform activity. Conclusion: Despite having a significant amount of total flavonoids, the extract did not present good antioxidant and photoprotective activities, demonstrating that the presence of flavonoids in an extract does not necessarily imply good antioxidant and photoprotective activities.

Keywords: Antioxidant, Photoprotection, Xylopia