Extraction of water-soluble polysaccharide and the antioxidant activity from Semen cassiae

Water-soluble polysaccharide was isolated from Semen cassiae using water for extraction and ethanol for deposition. The optimized conditions for polysaccharide isolation by orthogonal experiments were a sample to liquid ratio of 1:30 at 80°C for 3.5 hours; the yield of polysaccharide from Semen cassiae under these conditions was 5.46%. Different polysaccharides (SCPW-1, SCPW-2, SCPW-3, SCPW-4, SCPW-5, SCPS-1, SCPS-2) were obtained from the extract (i.e., crude polysaccharide) by DEAE-cellulose column chromatography. The polysaccharides obtained showed different structures by Fourier transform infrared therein the five elected from the seven kinds separated. The antioxidant activities of the extract were evaluated. The scavenging rates of the present extract on hydroxyl and superoxide were 43.32% and 64.97%, respectively, at a concentration of polysaccharide of 94.03 μg/mL, which was better than vitamin C at the same concentration. The scavenging rate of the present extract on 1,1-diphenyl-2-picrylhydrazyl was 13.33% at a polysaccharide concentration of 94.03 μg/mL, which was less than vitamin C at the same concentration.