Esenbeckia leiocarpa Engl. inhibits inflammation in a carrageenan-induced murine model of pleurisy

Abstract

The aim of this study was to investigate the anti-inflammatory effects of the crude hydroalcoholic extract (CHE) isolated from Esenbeckia leiocarpa Engl., and fractions and subfractions derived from it. Dried E. leiocarpa Engl. bark was macerated and extracted with ethanol to obtain the CHE. The n-hexane, ethyl acetate, aqueous and alkaloid fractions, as well as two alkaloid subfractions (polar and nonpolar) were obtained from the CHE. A preliminary analysis using thin-layer chromatography was performed. Capillary electrophoresis, physical characteristics and spectral data produced by IR analysis and nuclear magnetic resonance (¹H and ¹³C NMR), and mass spectrometry analysis were used to identify and elucidate the structure of the major compounds. Swiss mice were used in a carrageenan-induced pleurisy model. Pro-inflammatory parameters (leukocyte and exudate concentrations, myeloperoxidase and adenosine-deaminase activity, and nitrate/nitrite, interleukin 1β and tumour necrosis factor α levels) were quantified in exudates at 4 h after carrageenan-induced pleurisy in mice. The dihydrocorynantheol alkaloid was isolated as the majority compound in the CHE, ethyl acetate and alkaloid fractions, and in the polar and nonpolar alkaloid subfractions. The CHE, fractions and subfractions inhibited the increases in leukocyte and exudate concentrations, myeloperoxidase and adenosine-deaminase activity, and nitrite/nitrate, interleukin 1β, and tumour necrosis factor α levels (P<0.05) in the fluid secreted from the pleural cavity of the carrageenan-treated mice. E. leiocarpa Engl. showed significant in vivo anti-inflammatory action by inhibiting the inflammation caused by carrageenan. This effect may be, in part, due to the dihydrocorynantheol alkaloid, which was identified as the majority compound isolated from E. leiocarpa bark.