Evidence of Bioactive Compounds from Vernonia polyanthes Leaves with Topical Anti-Inflammatory Potential

Vernonia polyanthes Less. (Asteraceae), popularly known as "assa-peixe", is a plant species used in Brazilian traditional medicine for the treatment of cutaneous damage, cicatrization, inflammation, and rheumatism. Based on these ethnopharmacological findings, the current study evaluated the topical anti-inflammatory effects of the hexane (HEVP) and ethyl acetate (EAEVP) extracts from V. polyanthes leaves in experimental models of skin inflammation. Chemical characterization was carried out by HPLC-UV/DAD analysis. Anti-inflammatory activity was evaluated using Croton oil-, arachidonic acid (AA)-, phenol-, ethyl phenylpropiolate (EPP)-, and capsaicin-induced ear edema models in mice. Histopathological evaluation and measurements of myeloperoxidase (MPO) and N-acetyl-β-d-glucosaminidase (NAG) enzymes were also performed. Rutin, luteolin, and apigenin were identified in EAEVP. Topically applied HEVP and EAEVP significantly (p < 0.05, p < 0.01 or p < 0.001) reduced edema induced by five different irritants at the doses tested (0.1, 0.5 and 1.0 mg/ear). Histopathological analysis revealed a reduction of edema, inflammatory cell infiltration, and vasodilation. In addition, the enzymes activity (MPO and NAG) in the ear tissues was reduced by the topical treatment of HEVP and EAEVP (p < 0.05, p < 0.01 or p < 0.001). The results suggest that V. polyanthes leaves are effective against cutaneous damage, which support its traditional use and open up new possibilities for the treatment of skin disorders.