Structural characterization of a low-molecular weight linear O-acetyl-glucomannan in Lilium lancifolium from Tibet and its protected H2O2-induced oxidative stress in HUVEC cells

Abstract

AbstractIn recent years, the biological activity of plant polysaccharides has received increasing attention. Polysaccharides, as one of the main components of lilies, have pharmacological effects in regulating immunity, anti-tumor, antioxidant, antibacterial, and hypoglycemic effects. To systematically analyze the structural characteristics of the polysaccharide, the polysaccharide LP-1 was prepared from Lilium lancifolium bulbs by water extraction and ethanol precipitation, ion exchange chromatography and gel filtration chromatography. Structural characterizations show that the weight-average relative molecular weight of LP-1 is 5.3 kDa. LP-1 consists of mannose and glucose at a molar ratio of 1.4:1. Its primary structure is Glcp-α-D-(1 → {4)-β-D-Glcp-(1 → 4)-β-D-2-O-acetyl-Manp-(1 → [4)-β-D-Glcp-(1 → 4)-β-D-Glcp-(1 → 4)-β-D-Manp-(1 → 4)-β-D-Manp-(1 → 4)-β-D-Manp-(1 → 4)-β-D-Manp-(1]2}2 → 4)-α-D-Glcp. Acetylation occurs at the O-2 site of mannose. Acetyl substitution degree is 8.21%. The results of structure elucidation showed that LP-1 was a low-molecular weight linear O-acetylated glucomannan. The results of oxidative stress experiments indicate that LP-1 exerts antioxidant effects on HUVEC by activating the Nrf2/HO-1 signaling pathway, thereby improving endothelial cell damage induced by H2O2, and has the potential to be developed as an antioxidant drug. Graphical Abstract