Ultrasound-Assisted Extraction and Analysis of Antioxidation and Hypolipidemia Activities of Polysaccharides from Lilium brownii var. viridulum

Lilium brownii var. viridulum is one of the main traditional edible and medicinal lily in China. This study aimed to explore the extraction technology, physicochemical properties and functional activity of polysaccharide from Lilium brownii var. viridulum, used Lilium brownii var. viridulum scales as materials, polysaccharide yield as the index, solid-liquid ratio, extraction time and extraction temperature as factors to optimize the extraction process of lily polysaccharide. Then the polysaccharide was purified through removing protein. The physicochemical properties of the polysaccharides were analyzed, and the antioxidant and lipid-lowering abilities were measured in vitro. The results showed that the optimal extraction conditions were the material to liquid ratio 1:20 g/mL, extraction time 20 min, extraction temperature 75℃, and polysaccharide yield was 11.98%. The contents of total sugar, uronic acid and protein of crude polysaccharide were 58.46%, 8.06% and 10.85%, respectively. After deproteinization, the contents of total sugar and uronic acid of polysaccharide were increased to 84.78% and 15.41%, respectively, and the content of protein was reduced to 4.73%. The scavenging rates of 10 mg/mL deproteinized polysaccharide for DPPH and ABTS⁺ free radicals were 8.75% and 38.59%, respectively, which were lower than those of control V_C. The inhibition rate of deproteinized polysaccharide for pancreatic lipase was 85.78%, which was higher than that of the control orlistat, indicating good inhibit pancreatic lipase effect in vitro. These results would provide a basis for further study on the structure-activity relationship and development of potential functional food, and provide theoretical reference for the application of lily.