Characterisation of antioxidant and antiproliferative acidic polysaccharides from Chinese wolfberry fruits

► Wolfberry fruit polysaccharides (WFPs) exhibited dose-dependent antioxidant and antiproliferative effects. ► MCF-7 cells were more responsive to WFP treatment than A549 and LoVo cells. ► WFPs induced apoptosis and arrest at the G0/G1 phase in MCF-7 cells with DNA damage. ► WFPs are involved in an ROS-dependent apoptosis pathway in MCF-7 cells. Wolfberry fruit polysaccharides (WFPs) were isolated by hot-water extraction and ethanol precipitation. With HPLC analysis, WFPs were for the first time identified as acidic polysaccharides with galacturonic acid being the main component monosaccharide (24.9%), followed by galactose (21.3%), arabinose (18.5%), and glucose (15.9%), accounting for up to 80.6% of the molar percentage. WFPs exhibited a high antioxidant activity and a dose-dependent antiproliferative effect, with IC50 values of 134.9, 70.1 and 138.4μg/mL against A549, MCF-7 and LoVo cancer cells after 48h of incubation as estimated by MTT assay, respectively. Flow cytometry analysis showed that WFPs exerted a stimulatory effect on apoptosis of MCF-7 cells, and induced the cell-cycle arrest at the G0/G1 phase, with the observation of intracellular ROS production and DNA damage. The present study demonstrated that these polysaccharides might have the potential to provide significant natural defence against human cancer.