Antioxidant and antihyperlipidemic activities of purified polysaccharides from Ulva pertusa

Several studies have reported that ulvan from the alga Ulva pertusa (Chlorophyta) exhibits substantial antioxidant and antihyperlipidemic activities; however, which group of heteropolysaccharides play roles in these activities remains unknown. To identify the components of ulvan that possess biological activity, we used a DEAE-Sepharose fast-flow column. Two purified polysaccharides (F1 and F2) were detected and their physicochemical properties, antioxidant and antihyperlipidemic activities were analyzed. F1 (average molecular weight of 190 kDa) was composed of rhamnose, xylose, and glucose; F2 (average molecular weight of 83 kDa) was composed of rhamnose and xylose. Both polysaccharides showed significant antioxidant activities especially superoxide radical-scavenging power against ascorbic acid the half maximal inhibitory concentration (IC50) of which was 3.5 mg mL−1 (P < 0.05). Treatment of hyperlipidemic Kunming mice with F1 and F2 resulted in a significant decrease in serum total cholesterol, triglycerides, and low-density lipoprotein cholesterol, and a significant increase in high-density lipoprotein cholesterol. The results suggested that purified polysaccharides conferred greater biological activity than raw polysaccharides extracted from ulvan. These results indicated that F1 and F2 may be potential sources of natural antioxidants and therapeutic agents for hyperlipidemia.