Topical anti-inflammatory effect of Caryocar coriaceum Wittm. (Caryocaraceae) fruit pulp fixed oil on mice ear edema induced by different irritant agents

Aim of the study: Caryocar coriaceum Wittm. fruit pulp fixed oil (CCFO) has been widely employed by communities from Brazil Northeastern in the treatment of skin inflammation, respiratory affections, wound healing and muscle pain. In this study, we evaluated the topical effect of CCFO against different irritant agents in vivo, in order to verify its antiedematous effect as well to unravel its tentative mechanisms of action. Materials and methods: CCFO was obtained from Calyocar coriaceum fruits using ethyl acetate as solvent. Ear edema provoked by the application of Croton oil (single and multiple applications), arachidonic acid (AA), capsaicin, phenol and histamine to Swiss mice was used to evaluate the topical anti-inflammatory effect of CCFO. Histological analysis from mice ears sensitized with Croton oil and AA single application was also performed. Results: Crude CCFO (20 mu L/ear) demonstrated significant topical antiedematous effect against Croton oil single (inhibition of 32.0%; P < 0.05) and multiple (41.4% after 9 days, P < 0.001) applications, AA (inhibition of 49.7%; P < 0.01) and phenol (inhibition of 38.8%; P < 0.001). In contrast, CCFO did not antagonize the edema caused by topical treatment with capsaicin and histamine when compared to control group (P > 0.05). Histological analysis also revealed that CCFO was able to reduce the edema and the influx of inflammatory cells in mice ears sensitized with Croton oil and AA. Conclusions: CCFO exhibited a similar profile of topical anti-inflammatory activity to that of drugs that classically modulate the production of arachidonic acid metabolites. The study also indicates the potential application of CCFO as an important herbal medicine to be used against skin inflammatory diseases. (C) 2010 Elsevier Ireland Ltd. All rights reserved.