Structural characterization of Lanzhou lily (Lilium davidii var. unicolor) polysaccharides and determination of their associated antioxidant activity

Backgroud: The Lanzhou lily (Lilium davidii var. unicolor) is the only Lilium species that is used for both culinary and medicinal purposes in China. Its bulbs contain various bioactive substances, such as polysaccharides, saponins and colchicine. Lanzhou lily polysaccharides are known to have anti-immunity, anti-tumor and anti-oxidation functions.

Results: This study used a Box-Behnken design to optimize the ultrasound-assisted extraction of Lanzhou lily polysaccharides. Compared to other enzymes, trypsin significantly increased the polysaccharide yields, while the protein content of polysaccharides extracted with trypsin was lowest. Monosaccharide mainly includes glucose (> 50%) and mannose (> 10%). DPPH radical scavenging activity, chelating activity, total antioxidant capacity and hydroxyl radical scavenging activity of Lanzhou lily polysaccharides extracted with trypsin were stronger than those extracted without enzymes (control). Structural characteristics of Lanzhou lily polysaccharides extracted with trypsin and extracted without enzymes were characterized by scanning electron microscopy (SEM) and nuclear magnetic resonance spectroscopy (NMR). When WAP and TRP concentrations were 200 μg/mL, Raw264.7 proliferation rates were 101.69% and 159.41%, respectively.

Conclusions: The Lanzhou lily polysaccharide was identified as α-(1→6)-D-glucan. Consequently, the effects of both potential antioxidant and proliferative activity of trypsin is significant. This article is protected by copyright. All rights reserved.

Keywords: Lanzhou lily; NMR; antioxidant activity; polysaccharide; trypsin.