Extraction, characterization and biological activities of polysaccharides from Amomum villosum

In the present study, the extraction, purification, characterization and biological activities of polysaccharides from the seeds of Amomum villosum (ASP) were investigated. Firstly, the optimal parameters for the extraction of ASP were obtained by using a Box–Behnken Design as follows: extraction temperature 78.8 °C, extraction time 71.3 min and ratio of water to raw material 39.3 ml/g. Then, the crude ASP was sequentially purified by chromatography of DEAE-52 and Sephadex G-100, resulting in three purified fractions of ASP-1, ASP-2 and ASP-3. The results showed that ASP-3 had a larger molecular weight and higher contents of protein, sulfuric radical and uronic acid than the other polysaccharide fractions. Furthermore, ASP-3 showed relative stronger inhibitory activity on the growth of HepG2 cells. Finally, ASP had strong free radical scavenging activities in vitro and significantly prevented the formation of malondialdehyde and enhanced the activities of antioxidant enzymes in CCl4-induced liver injury mice.