Search

An antioxidant-active polysaccharide (WMP) with a molecular weight of 26.91 kDa was isolated from Mentha haplocalyx Briq by water extraction, ethanol precipitation and gel filtration. According to HPLC, methylation, GC-MS, and 1D/2D nuclear magnetic resonance spectroscopy, WMP is a heteropolysaccharide composed of Gal (84.2 %), Glc (9.8 %), Man (2.8 %) and Ara (3.2 %) with (1→6)-α-d-Galp and (1→4, 6)-α-d-Galp residues in the backbone and (1→6)-α-d-Galp and (1→6)-α-d-Glcp residues in the branch. The branch point was located at C-4 of (1→4, 6)-α-d-Galp residue with a branching degree of 19.71 %. WMP showed remarkably high scavenging ability for 1, 1-diphenyl-2-picrylhydrazyl (DPPH) and hydroxyl radicals, ferrous ion chelating activity and ferric reducing powder in vitro. In vivo result showed that WMP oral administration substantially increased the activities of antioxidant enzymes, including SOD, GSH-Px and CAT, and decreased MDA levels in the serum and liver of d-Gal-induced aging mice. Therefore, WMP can be an effective natural antioxidant.

Three acid polysaccharides obtained from Gynostemma pentaphyllum (Thunb.) Markino (named as GPA1, GPA2 and GPA3) using combination of water extraction, ion-exchange and gel permeation chromatography were subjected to composition analysis and valuated for the antioxidant activity. The sugar content of GPA1, GPA2 and GPA3 were 54.55%, 85.70% and 91.34%, respectively. Monosaccharide analysis showed that GPA1, GPA2 and GPA3 were all composed of Man, Rha, GlcA, GalA, Glc, Gal, Ara and Fuc, besides, GPA2 and GPA3 also contained Xyl. The molecular weight of GPA1, GPA2 and GPA3 were 19.6kDa, 10.6 kDa and 6.7 kDa, respectively. In vitro antioxidant assay, GPA1, GPA2 and GPA3 could scavenge 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical and hydroxyl radical, chelate ferrous ion and reduce ferric ion. The antioxidant activities of GPA3 were stronger than those of GPA1 and GPA2, suggesting that GPA3 has significant potential as a natural antioxidant agent.

The structure and antioxidant activity of a neutral polysaccharide (named as EFPN-1) from Epimedium koreanum Nakai were studied. Based on the results from high performance gel permeation chromatography, methylation GC–MS and 1D/2D nuclear magnetic resonance spectroscopy, EFPN-1 was a branched polysaccharide with a molecular weight of 21.9 kD and containing over 60% of glucose. Its backbone was composed of (1 → 4)-β- d -Glcp and (1 → 3)-β- d -Galp, branched partially at O-6 of both residues, with a degree of branching of 40.4% and terminated mainly with Ara and Gal, as well as trace amount of Gal. Antioxidant tests showed that EFPN-1 exhibited a strong capacity on DPPH and hydroxyl radical scavenging, ferrous ion chelation and reducing antioxidant powder. EFPN-1 has potential to be developed as a natural antioxidant.

The chemical characterization and antioxidant activities of water-soluble ginseng oligosaccharides from roots (WGOS-R), flowers (WGOS-F) and leaves (WGOS-L) of Panax ginseng C.A. Meyer obtained by hot water extraction were investigated. The sugar content of WGOS-R, WGOS-F and WGOS-L were 95.87%, 87.07% and 83.09%, respectively. The ginsenosides and total phenols content decreased in the order of WGOS-L>WGOS-F>WGOS-R. WGOS-R comprised only Glc, WGOS-F and WGOS-L comprised Glucose (Glc) and Rhamnose (Rha) in a molar ratio of 6.0:1.0 and 7.0:1.0, respectively. In vitro antioxidant tests showed that WGOS-R exhibited higher antioxidant activity than WGOS-F and WGOS-L. In vivo antioxidant tests showed that WGOS-R significantly enhanced activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px) and total antioxidant capability (T-AOC) in the serum and liver and decreased malondialdehyde (MDA) level in the serum and liver.