Structural characterization and biological activities of a novel polysaccharide from Phyllanthus emblica

Abstract

A novel water-soluble polysaccharide named PEPW80-1, with a molecular mass of 4.7 kDa, was isolated from the pulp tissues of Phyllanthus emblica, and purified by sephadex G-100 column and sephacryl S-300 HR chromatography. The structural features of PEPW80-1 were investigated by a combination of acid hydrolysis, periodate oxidation-Smith degradation, methylation analysis, gas chromatography-mass spectrometry, scanning electron microscope, Fourier transform infrared spectroscopy, and nuclear magnetic resonance spectroscopy. The results showed that PEPW80-1 had a specific optical rotation of [α]25/D = +113° (c = 0.5 mg/mL) and its backbone composed of (1,3)-linked-β-L-rhamnose and (1,3,6)-linkage-β-D-galactose, with two branch chains of (1,4)-linked-α-D-galactose and (1,6)-linked-β-D-galactose and terminated with 1-α-L-arabinose. The antioxidant assays showed that PEPW80-1 possess 2,2-diphenyl-1-picrylhydrazyl radical-scavenging activity and hydroxyl radical-scavenging activity, enhancing reductive power. The results of immunomodulatory assays in vitro showed that PEPW80-1 could promote the proliferation of mouse splenocytes. Those proposed that PEPW80-1 might be developed as a potential value-added product with the activities of immunomodulator and free-radical inhibitors.