Physicochemical Properties and Cytoprotective Effects on PC12 Cells of Polysaccharides from Belamcanda chinensis (L.) DC. Obtained via a Gradient Ethanol Precipitation Method

Given that the preparation method of polysaccharides affects the functional properties, four types of acidic polysaccharides (BCP30-1a, BCP50-1a, BCP70-1a, and BCP90-1a) were prepared using the gradient ethanol precipitation method. Then, a series of chemical and instrumental analysis techniques were used to compare structural characteristics and morphology. Neuroprotective effects were explored using OGD/R-induced PC12 cells. The results showed that BCP30-1a, BCP50-1a, BCP70-1a, and BCP90-1a had similar characteristic groups and contained both β-glycosidic and α-glycosidic bonds. Their molecular weights, in descending order, were 198.398 kDa, 184.690 kDa, 184.556 kDa, and 184.217 kDa, respectively. In addition, the four polysaccharides contained different proportions of glycosidic bonds, namely, Man<i>p</i>-(1→, →5)-Ara<i>f</i>-(1→, →3)-Gal<i>p</i> (or GalA<i>p</i>)-(1→, →4)-Glc<i>p</i>-(1→ and →3,6)-Gal<i>p</i>-(1→. BCP30-1a also contained a certain proportion of Gal<i>p</i>-(1→, and each polysaccharide had different microscopic characteristics and good thermal stability. Finally, BCP50-1a, BCP70-1a, and BCP90-1a exhibited good cytoprotective effects on PC12 cells based on the OGD/R model. These findings provide a novel regulatory strategy for the functional activity of BCPs and offer scientific evidence supporting application in the research field of ischemic stroke.