Croton antisyphiliticus Mart. attenuates the inflammatory response to carrageenan-induced pleurisy in mice

The aim of this study was to investigate the anti-inflammatory effect of the crude hydroalcoholic extract (CHE) from the aerial parts of Croton antisyphiliticus, its fractions and isolated compounds derived from it on the mouse model of pleurisy induced by carrageenan. The aerial parts of C. antisyphiliticus were dried, macerated and extracted with ethanol to obtain the CHE, which was fractionated by liquid–liquid extraction using solvents with increasing polarity to obtain hexane (Hex), ethyl acetate (EA) and aqueous (Aq) fractions. Vitexin and quinic acid were isolated from Aq fraction. Capillary electrophoresis analysis, physical characteristics and spectral data produced by infrared (IR), nuclear magnetic resonance (¹H and ¹³C NMR) and mass spectrometry analyses were used to identify and elucidate the structure of the isolated compounds. The experimental model of pleurisy was induced in mice by a single intrapleural injection of carrageenan (1 %). Leukocytes, exudate concentrations, myeloperoxidase (MPO) and adenosine-deaminase (ADA) activities and nitrate/nitrite (NOx), tumor necrosis factor-α (TNF-α) and interleukin-17 (IL-17) levels were determined in the pleural fluid leakage at 4 h after pleurisy induction. Animals pre-treated with CHE, Hex, EA, Aq, vitexin and quinic acid exhibited decreases in leukocytes, exudate concentrations, MPO and ADA activities and NOx levels (p < 0.05). Also CHE, Hex, EA and vitexin but not quinic acid inhibited TNF-α and IL-17 levels (p < 0.05). C. antisyphiliticus caused anti-inflammatory effect by inhibiting the activated leukocytes, exudate concentrations, NOx, TNF-α, and IL-17 levels. The compounds vitexin and quinic acid may be responsible for this anti-inflammatory action.