Effect of pequi tree Caryocar coriaceum Wittm. leaf extracts on different mouse skin inflammation models: inference with their phenolic compound content

Caryocar coriaceum Wittm. (pequi) has been popularly used in Northeastern Brazil in the treatment of inflammation, pain and respiratory affections. This study evaluated the topical anti-inflammatory activity of C. coriaceum hydroethanolic extract (CCHE) and methanolic fraction (CCMF) from pequi tree leaves against different skin sensitizer agents (arachidonic acid, croton oil, phenol and histamine), as well their antioxidant activity and phenolic compound profile. High performance liquid chromatography with diode array detection (HPLC-DAD) analysis pointed the presence of chlorogenic acid, rutin, quercetin and lower concentrations of caffeic and gallic acids. Both CCHE and CCMF 1 mg/ear demonstrated significant topical anti-inflammatory effect against arachidonic acid, phenol and histamine single application (antiedematous effect ranging from 48 to 69% for CCHE and 36 to 64% for CCMF; P < 0.05 vs. negative control). In contrast, both extracts did not antagonize the croton oil single application-induced ear edema when compared with the control group (P > 0.05). Additionally, both extracts exhibited strong DPPH• free radical scavenging activity in vitro (EC50 = 5.02 ± 4.37 μg/ml for CCMF and 6.06 ± 4.03 μg/ml for CCHE). Together, the results give important support that CCHE and CCMF (and their phenolic compounds, according to previous data from literature) could exert topical anti-inflammatory activity by possibly modulate the local production of inflammatory mediators including histamine, arachidonic acid metabolites and reactive oxygen species. Key words: Topical anti-inflammatory activity, mouse ear edema, dermatitis, Caryocar coriaceum, polyphenols, skin disorders.