Structural characters and protecting β-cells of a polysaccharide from flowers of Inula japonica

Our previous studies found that the crude polysaccharides (IJP) from flowers of Inula japonica exhibited significantly anti-diabetic activity in alloxan or MLD-STZ induced diabetic mice. In this study, we will trace an active polysaccharide from IJP and investigate its physico-chemical property and its protective mechanism on islet cell damage. The result showed that an active polysaccharide (IJP-B-1) was isolated from IJP, its molecular mass was 3.7 × 104 Da. IJP-B-1 was composed of rhamnose, arabinose, xylose, mannose, glucose, galactose and galactocuronic acid. Its major backbone structure was (1 → 3, 6)-linked-galactose and other branched residues. IJP-B-1 could protect pancreatic cells against STZ impairment at 50 μg/mL and scavenge OH and O2 radicals to decrease reactive oxygen generation in islet-cells in vitro. These results suggested that IJP-B-1 might be useful for protecting β-cells and against oxidative stress as an anti-diabetic candidate drug in future.