Comparison on structural characterization, chain conformation, and neuroprotective activity of polysaccharides extracted from Albizia julibrissin Durazz. bark with hot water and ultrasound

A comparative and multidimensional approach is employed herein to assess how ultrasound affects the extraction yield, structural features, and chain conformation of Albizia julibrissin Durazz. bark polysaccharides. The results showed that ultrasound treatment can significantly (P < 0.05) improve the extraction yield, and the optimal extraction process parameters were 50 min, 70 ℃, 30 mL/g, and 201 W. In addition, this study found that ultrasound can alter the chemical composition, characteristic group content, monosaccharide composition molar ratio, molecular weight, and even relative content of glycosidic bond types of A. julibrissin bark polysaccharides. Interestingly, the ultrasound treatment followed the midpoint chain scission model and transformed HWE-AJPP1 from a flexible chain conformation to UAE-AJPP1 exhibiting a spherical structure. And the involvement of ultrasound also altered the relatively tight big block-like morphology of HWE-AJPP1, and UAE-AJBP1 showed remarkable thermostability. Compared with HWE-AJBP1, UAE-AJBP1 significantly (P＜0.001) enhanced the viability of injured oxygen glucose deprivation/reoxygenation-induced PC12 cells. And UAE-AJBP1 effectively restored mitochondrial membrane potential, attenuated intracellular ROS levels. The findings of this work establish a solid basis for further exploiting ultrasound-prepared polysaccharides from A. julibrissin bark and strongly supports ultrasound’s wider application in polysaccharide-related fields.