Protective effects of polysaccharides from Psidium guajava leaves against oxidative stresses.

The aim of this study was to analyze antioxidant properties of a polysaccharide isolated from Psidium guajava leaves (PS-PGL) in vitro including its radical scavenging activities and protective effects against damage to cells as well as in vivo in zebrafish. The water extract of P. guajava leaves (WE-PGL) and PS-PGL showed strong radical scavenging effects in terms of 2,2-diphenyl-1-picrylhydrazyl (DPPH), hydroxyl, and alkyl radical. Compared to WE-PGL, PS-PGL enhanced all scavenging activities and in particular strongly scavenged the hydroxyl radical (50% inhibitory concentration [IC50], 0.02mg/mL). In addition, PS-PGL exerted a protective effect against hydrogen peroxide-induced oxidative stress and against toxicity to Vero cells. Furthermore, in vivo experiments using zebrafish embryos indicated that treatment with hydrogen peroxide decreased the survival rate and heart-beating rate of zebrafish embryos, whereas these problems were reduced by PS-PGL treatment. Moreover, PS-PGL inhibited hydrogen peroxide-induced reactive oxygen species (ROS) production, lipid peroxidation, and cell death. Taken together, these results suggest that PS-PGL may be useful as a beneficial antioxidant material in the food and cosmetic industries.

Antioxidant activity of polysaccharide purified from Acanthopanax koreanum Nakai stems in vitro and in vivo zebrafish model.

In this study, the antioxidative effects of a purified polysaccharide isolated from the stems of Acanthopanax koreanum Nakai (ASP) on hydrogen peroxide-induced oxidative stress was investigated both in vitro and in vivo using a zebrafish model. A. koreanum Nakai stem was hydrolyzed using five carbohydrases and five proteases for the enzyme-assistant extraction. Of the enzyme-assistant extracts, the Protamex extract exhibited the highest yield and a potent scavenging activity against free radicals. Ethanol-added separation and anion exchange chromatography were conducted to identify the active polysaccharide. The purified polysaccharide significantly scavenged hydrogen peroxide and reduced hydrogen peroxide-induced cell death in Vero cells and in zebrafish. The results reveal that ASP is a useful antioxidant polysaccharide and might be available for relevant industrial applications.