A comparative study on the antioxidant activities of an acidic polysaccharide and various solvent extracts derived from herbal Houttuynia cordata

This study is designed to compare the antioxidant potential of a water-soluble polysaccharide (HCP) with solvent extracts (water, ethanol, ethyl acetate and chloroform) from Houttuynia cordata Thunb. The results showed that polar water extract exhibited the highest reducing power and scavenging activities against 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, superoxide radical and hydroxyl radical, which were correlated with its high level of biopolymer HCP. Furthermore, the active HCP was identified as an acid hetero-polysaccharide by a rapid HPLC technology within 20 min, and galacturonic acid (29.4%) and galactose (24.0%) were approved as the prominent components of HCP, followed by rhamnose (17.2%), arabinose (13.5%), glucuronic acid (6.8%), glucose (5.3%), xylose (2.1%) and mannose (1.8%) in the molar percentages. This finding suggests that HCP is one of the main active ingredients responsible for antioxidant effect of H. cordata, which might be valuable as a natural antioxidant source applied in both healthy medicine and food industry.