Cariniana domestica fruit peels present topical anti-inflammatory efficacy in a mouse model of skin inflammation

To investigate the topical anti-inflammatory activity of the crude extract of Cariniana domestica fruit peels (CdE), its dichloromethane, n-butanol, and ethyl acetate (EtAc) fractions, and steroids (β-sitosterol, lupeol, and stigmasterol) isolated from the EtAc fraction in models of irritant contact dermatitis (ICD) croton oil-induced in mice. We induced skin inflammation by single (acute; 1 mg/ear) and multiple (chronic; 0.4 mg/ear) croton oil application. We topically applied C. domestica (CdE, fractions, and gel formulations) and β-sitosterol, lupeol, and stigmasterol immediately after applying croton oil. HPLC-DAD chromatography of the EtAc fraction and stability of the gel formulations were verified. HPLC-DAD of the EtAc fraction revealed the stigmasterol, lupeol, and β-sitosterol presence. CdE and EtAc fraction gels showed no organoleptic or pH changes at room temperatures. CdE and dichloromethane, n-butanol, and EtAc (1 mg/ear) fractions decreased the acute ear edema with maximum inhibition (Imax) of 97 ± 2, 86 ± 1, 81 ± 4, and 95 ± 2%, respectively. CdE and EtAc fraction gel presented similar effects, with respective Imax of 85 ± 6% (3%;15 mg/ear) and 82 ± 2% (1%;15 mg/ear). β-sitosterol (7.5 μg/ear), lupeol (10 μg/ear), and stigmasterol (5.7 μg/ear) also reduced this parameter by 46 ± 8, 51 ± 7, and 62 ± 7%, respectively. All topical treatments reduced the inflammatory cells’ infiltration in the acute ICD model. CdE reduced the ear edema by 77 ± 4% (1 mg/ear) and the inflammatory cell infiltration in the chronic ICD model. CdE’s anti-inflammatory effect was accompanied by a minimum development of adverse effects. C. domestica demonstrates a promising potential for the development of a topical anti-inflammatory agent.