Caracterização química e efeitos farmacológicos de produtos derivados de Palicourea rigida Kunth (Rubiaceae)

Abstract

Palicourea rigida Kunth, belonging to the Rubiaceae family, has been used in folk medicine for the treatment of inflammation and infections of the urinary tract, female reproductive tract and skin conditions. From the chemical point of view, triterpenes, iridoids, flavonoids and alkaloids have been identified in species. The aim of this study was to perform a chemical characterization and evaluate the topical anti-inflammatory and wound healing activities of P. rigida. Dried and powdered leaves were extracted in ethanol PA by static maceration followed by rota-evaporation for obtaining ethanol extract (EEPR). EEPR was subjected to partition liquid/liquid to obtain the hexane, dichloromethane, ethyl acetate and butanol fractions. EEPR was analyzed by UPLC-UV-MS, while the hexane fraction by GC-MS. The ethyl acetate fraction was separated by column chromatography with Sephadex LH-20 and the isolated compound was elucidated by 1H and 13C NMR and mass spectrometry. From the EEPR, a dermatological formulation was developed using the cream-based Lanette® (cEEPR). The topical anti-inflammatory activity of EEPR was evaluated by the ear edema models in mice Swiss using croton oil, arachidonic acid, capsaicin and phenol. The wound healing activity of EEPR and cEEPR was investigated in Wistar rats through the model of skin lesions. Histopathological analysis and activity of the enzyme myeloperoxidase (MPO) and N-acetyl- β-D-glucuronidase (NAG) were also determined. Loganin and quercetin 3-6-O-acetyl-β- glucoside were identified in EEPR by UPLC-UV-MS, while palmitic acid, phytol, linoleic acid, squalene, gamma tocopherol, vitamin E, campesterol, stigmasterol and sitosterol were characterized in the hexane fraction by GC-MS. From the fraction in ethyl acetate, the flavonoid quercetin 3-O-β-D-glucoside was isolated and its structure elucidated. EEPR showed topical anti-inflammatory activity in different models by reducing the the mass and thickness of the edema, as well as through the decrease in the inflammatory process observed by histopathological analysis and inhibition of the MPO and NAG activities. EEPR and cEEPR demonstrated wound healing activity by decrease the area of lesion and increase the contraction degree, as well as stimulate the healing process and reduce the MPO and NAG activities. The results indicate that P. rigida is rich in bioactive substances which may be responsible for the anti-inflammatory and wound healing activities.