Extraction, structure characterization and biological activity of polysaccharide from coconut peel

AbstractTaking coconut peel as raw material, the extraction process of coconut peel polysaccharide (CPP) was optimized by boiling water extraction. The coconut peel polysaccharide was characterized by UV, IR, SEM, 1D NMR and 2D NMR spectra. At the same time, the molecular weight and monosaccharide component were analyzed by gel chromatography and ion chromatography, respectively. Antioxidant activity of coconut peel polysaccharide and its derivatives in vitro was evaluated by scavenging ABTS and DPPH radicals and O2−·, and the anti HepG2 proliferation activity in vitro was also carried out. The results showed that the molecular weight of coconut peel polysaccharide was 1.20 × 105 Da, which was mainly composed of arabinose (Ara), galactose (Gal), glucose (Glu), xylose (Xyl) and galacturonic acid (Gal-A). The main chain structure of polysaccharides detected by 1D and 2D NMR spectrum was → 4)-α-D-Glcp (1 → . In vitro antioxidant test showed that coconut peel polysaccharide and its derivatives had a certain scavenging effect on ABTS and DPPH free radical and O2−·. With the increase of polysaccharide concentration, the scavenging ability was gradually increased. In addition, coconut peel polysaccharide and its derivatives showed significant antiproliferative activity against HepG2 cells in vitro. Graphical Abstract