Structure and biological activity of polysaccharides from Nitraria sibirica pall fruit

Abstract Physicochemical properties, structural features, and biological activities of polysaccharide fractions isolated from Nitraria sibirica (NS) pall fruit were investigated. Structural characterization was carried out using Fourier transform infrared spectroscopy, gas chromatography, partial acid hydrolysis, peroxide oxidation, Smith degradation, and nuclear magnetic resonance. The results showed that three of the polysaccharide fractions with average molecular weights of 21.5, 14.4, and 49.4 kDa were composed of different molar ratios of rhamnose, galactose, glucose, mannose, and arabinose, and have different chain structures and glycosidic linkages. The structural characteristics of polysaccharide fractions were also evaluated by scanning electron microscopy-energy dispersive X-ray spectroscopy, X-ray diffraction, and thermogravimetric analysis. NSP-3 exhibited a better biological activity compared to NSP-1 and NSP-2, with IC50 value of anti- MCF-7 at 50.89 μg/mL, and inhibition rate against cyclooxygenase-2 was 85.60% at a concentration of 100 μg/mL. These results suggested that polysaccharides obtained from N. sibirica fruits could be a promising ingredient for health-beneficial functional foods.