Structural characterization of water-soluble polysaccharides from Nitraria retusa fruits and their antioxidant and hypolipidemic activities.

The structure, antioxidant and anti-hyperlipidemic activities of polysaccharides from Nitraria retusa fruits (named as NRFP) were investigated. The NRFP fraction, with a molecular weight of 66.5 kDa, was composed of a β-(1 → 3)-glucan, containing neutral sugars (69.1%) but also uronic acids up to 23.1% due to pectin structure. The monosaccharide composition highlighted a polymer composed of glucose (41.4%), galacturonic acid (30.5%), galactose (12.6%), arabinose (11.8%) and rhamnose (3.70%). In the antioxidant assays, NRFP exhibited effective total antioxidant capacity (IC50  = 7.82 mg/mL), scavenging activities on DPPH radical (IC50  = 0.87 mg/mL) and hydrogen peroxide (IC50  = 2.03 mg/mL). In addition, NRFP proved protective effects on H2 O2 induced hemolysis (IC50  = 66.2 μg/mL). In vivo NRFP reduced the hyperlipidemia, hepatotoxicity, cardiovascular and coronary diseases induced by Triton X-100.