Extraction, purification and characterization of polysaccharides from Hawk tea

•The polysaccharide extraction from Hawk mature leaf tea (HMP) was optimized by BBD.•Two fractions, HMP-1 and HMP-2, were purified from crude HMP.•Two fractions were mainly composed of arabinose, galactose, glucose and mannose.•HMP-1 exhibited a good antioxidant activity in vitro. In the present study, the extraction, purification and characterization of polysaccharides from Hawk mature leaf tea (HMP) were investigated. The optimal extraction parameters were obtained by using a Box–Behnken design as follows: extraction temperature 88.9°C, extraction time 128.2min and ratio of water to solid 11.4mL/g. The crude HMP was sequentially purified by chromatography of DEAE-52, and two purified fractions, HMP-1 and HMP-2, were obtained. HMP-1 and HMP-2 were mainly composed of arabinose, galactose, glucose and mannose with the molecular weight of 133 and 100kDa, respectively. For antioxidant activities in vitro, HMP-1 had strong 2,2-diphenyl-1-picryl-hydrazyl (DPPH) radical scavenging activity and ferric reducing activity power (FRAP). These results provide a scientific basis for the further use of polysaccharides from this traditional herb tea.