Physico-chemical characterization and pharmacological activities of polysaccharides from Opuntia microdasys var....

The aim of this study is to isolate pectin from peel (WNPE) and pulp (WNPU) of Opuntia microdasys var. rufida's (OMR) cladodes and to characterize these polysaccharides by size exclusion (SEC/MALS/VD/DRI), gas chromatography coupled to mass spectrometer (GC-MS), nuclear magnetic resonance (¹H NMR), and Fourier transform infrared spectroscopy (FTIR) analysis. The polysaccharides were extracted in neutral aqueous media followed by ethanol precipitation and dialysis. Both WNPE and WNPU are mainly composed of uronic acids and some neutral sugars such as arabinose, galactose, rhamnose and mannose. Their molecular weight range from 2,180,000 and 4,920,000g/mol. The in-vivo pharmacological activities (anti-inflammatory, analgesic and gastroprotective activities) have been performed. The extracted pectin (50-100mg/kg, i.p. (intraperitoneal)) inhibited, in a dose-related manner, both carrageenan-induced paw edema in rats and Xylene-induced ear edema in mice. A dose-dependent action was obtained against chemical (writhing test) and thermic (hot plate test) stimuli, respectively, with doses of 50 and 100mg/kg. Moreover, a considerable gastroprotective effect was observed with these two biopolymers, the gastric ulcer was attenuated until 67.67% for WNPE and 81.93% for WNPU, at the dose of 100mg/kg.