Macroscopic, biochemical and hystological evaluation of topical anti-inflammatory activity of Casearia sylvestris (Flacourtiaceae) in mice

Ethnopharmacological relevance: Inflammatory skin diseases presents high prevalence and lack of alternatives that can be used for self-care by the population. Casearia sylvestris is a plant used topically in different communities in Brazil, to treat wounds or promote cutaneous healing. To evaluate the topical anti-inflammatory activity for the crude hydroalcoholic extract of Casearia sylvestris (HCE-CS) in the models of single or multipe administration of chroton oil to induce ear edema in mice.

Materials and methods: Experimental study using male Swiss mice (25-35g) kept under constant conditions in the Laboratory of Experimental Neuroscience (LaNEx)-UNISUL. Edema was induced in both models, respectively, by the single or multiple application of croton oil (CO, 2.5%, in 20μl) on the external surface of the ear. The different groups of animals (n= 8) received different treatments: vehicle, dexamethasone (DEXA) or different doses of HCE-CS. Edema was evaluated macroscopically for 6 h (early edema) or 8 days (late edema) after the first application of the CO and immediately after the animals were submitted to euthanasia for the collection of the samples (treated ears). For early edema, the tissue was biochemically evaluated for myeloperoxidase activity (MPO) and levels of nitrite/nitrate. In the late edema model, the ears were histologically evaluated for general morphometry, degranulated and non-degranulated mast cells, as well as acanthosis.

Results: Topic treatment with HCE-CS significantly reduced the early and late edema, as well as MPO activity and tissue levels of nitrite/nitrate. Finally, in the late edema model there was a lower density of degranulated mast cells in relation to the vehicle treated group and decreased thickness of the epidermis (acanthosis).

Conclusion: These results suggest a possible benefit of topical treatment with HCE-CS in inflammatory conditions of the skin.

Keywords: Casearia sylvestris; inflammation; skin conditions.