Characterization of Polysaccharides with Antioxidant and Hepatoprotective Activities from the Edible Mushroom Oudemansiella radicata

Abstract

The preliminary structure, in vitro antioxidant and in vivo hepatoprotective activities of water-soluble polysaccharides (ORWP) and alkali-soluble polysaccharides (ORAP), prepared from the mushroom Oudemansiella radicata, were investigated. Both ORWP and ORAP were heteropolysaccharides with mannose, glucose and galactose being the main monosaccharide components. Regarding the antioxidant activities, ORWP and ORAP showed effective 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, hydrogen peroxide scavenging activity and lipid peroxidation inhibitory effects, as well as moderate reducing power and Fe²⁺ chelating activity. For the hepatoprotective activity, administration of ORWP and ORAP prevented the increase in serum alanine aminotransferase and aspartate aminotransferase activities in a carbon tetrachloride-induced acute liver damage model, suppressed hepatic malondialdehyde formation and stimulated the activities of hepatic superoxide dismutase and glutathione peroxidase. Thus, we speculate that ORWP and ORAP may protect the liver from CCl₄-induced hepatic damage via antioxidant mechanisms.

Keywords: Oudemansiella radicata; antioxidant; hepatoprotective; polysaccharides.

Figure 1

FT-IR spectrum of (a) ORWP and (b) ORAP.

Figure 2

Antioxidant activity of ORWP and ORAP. (a) scavenging of DPPH radicals; (b) inhibitory effect on lipid peroxidation; (c) hydrogen peroxide scavenging activity; (d) reducing power; and (e) Fe²⁺ ion chelating activity. The values are representative of three separate experiments.

Figure 3

Effects of ORWP and ORAP on the activity of serum AST (a) and ALT (b) in CCl₄-treated mice. The values represent means ± SD of eight mice/group. ^### p < 0.001 versus normal control, *** p < 0.001, ** p < 0.01 and * p < 0.05 versus CCl₄-intoxicated group.

Figure 4

Effects of ORWP and ORAP on hepatic (a) MDA content; (b) GSH-Px activity and (c) SOD activity in CCl₄-treated mice. The values represent means ± SD of eight mice/group. ^### p < 0.001 compared with control, *** p < 0.001, ** p < 0.01 and * p < 0.05 versus CCl₄-intoxicated group.

Figure 5

Effects of ORWP and ORAP on liver as disclosed by morphological analysis (×400 H&E staining). (a) normal control group; (b) CCl₄-intoxicated group; (c) bifendate positive control group (200 mg/kg) + CCl₄; (d) ORWP (100 mg/kg) + CCl₄; (e) ORWP (200 mg/kg) + CCl₄; (f) ORAP (100 mg/kg) + CCl₄; (g) ORAP (200 mg/kg) + CCl₄. Black arrows indicate necrotic zones; red arrows indicate lipid droplet accumulation.