Efeito anti-inflamatório e antioxidante da Solanum stipulaceum Willd. ex Roem. & Schult na inflamação cutânea em camundongos

Abstract

Solanum stipulaceum, popularly known as "sacatinga", is a plant endemic to the Brazilian Caatinga, traditionally used for gastric disorders. Scientific evidence supports its gastroprotective effects, attributed to bioactive compounds with antioxidant and antiinflammatory properties, and confirms the presence of phenolic acids and flavonoids, reinforcing the relevance of investigating its anti-inflammatory potential. This study aimed to evaluate the anti-inflammatory and antioxidant effects of the hydroethanolic extract of Solanum stipulaceum leaves (EHSs) and of 4-hydroxybenzoic acid in a mouse model of skin inflammation. Female Swiss mice were subjected to inflammation induction in the right ear by topical application of 12-O-tetradecanoylphorbol-13-acetate (TPA; 1 μg/ear in 20 μL acetone). Five minutes later, the animals received topical treatment with EHSs and AHB at different doses (0.3, 1.0, and 3.0 mg/ear), vehicle (acetone), or dexamethasone (0.05 mg/ear) as a positive control. The contralateral ears received only vehicle and served as paired controls. Six hours after inflammation induction, the animals were euthanized, and ear tissues were collected using an 8 mm punch for evaluation of edema (mass difference between ears), macroscopic analysis, histological analysis (dermo-epidermal thickness), myeloperoxidase (MPO) activity, cytokine quantification, total hydroperoxides, and catalase (CAT) activity. Compared to the vehicle + TPA group, topical treatment with EHSs (0.3, 1.0, and 3.0 mg/ear) and AHB (3.0 mg/ear) promoted significant reduction of edema (p < 0.0001 for EHSs; p = 0.0382 for AHB), of macroscopic inflammatory parameters (corroborated by histological findings), of dermoepidermal thickness (p = 0.0002; p = 0.0018; p = 0.0054, respectively), and of MPO activity (EHSs: EHSs: p < 0.0001; < 0.0001; p = 0.0003, respectively; AHB: p = 0.0145). At the dose of 3 mg/ear, EHSs also reduced IL-1β and IL-6 concentrations (both p < 0.0001), as did AHB (p = 0.013 and p = 0.0061, respectively), when compared to the vehicle + TPA group. Regarding oxidative stress parameters, treatment with EHSs decreased total hydroperoxides (p = 0.0062) and increased catalase activity (p = 0.0205). These findings demonstrate the anti-inflammatory and antioxidant properties of EHSs, with partial contribution of 4-hydroxybenzoic acid (AHB), reinforcing the pharmacological potential of this species as a candidate for the development of therapeutic strategies for inflammatory and oxidative skin disorders.