Polysaccharides from fruit calyx of Physalis alkekengi var. francheti: Isolation, purification, structural features and antioxidant activities

The conditions for extracting and purifying polysaccharides from fruit calyx of Physalis alkekengi var. francheti were investigated, including hot water extraction, ultrasonic wave-assistant extraction and enzyme extraction methods. Four polysaccharide fractions (PAVF I, II-a and III) were separated from the extracts of fruit calyx of P. alkekengi var. francheti using a DEAE anion-exchange column and Sephadex G-200 column. Their chemical compositions were determined in this study. On the basis of hydroxyl radical assay (OH), superoxide radical assay, 1,1-dipheny-l-2-picrylhydrazyl (DPPH) assay, the antioxidant activities of crude polysaccharide from fruit calyx of P. alkekengi var. francheti (FCP), PAVF I, II-a, -b and III were investigated. Among these contents, PAVF I has higher scavenging effects on DPPH, OH and superoxide anion-scavenging activities.