Effect of Chemical Modifications on the Structure, Antioxidant, and Hypoglycemic Activity of Prunus Cerasifera <i>Ehrh</i> . Polysaccharides

Chemical modification effectively modulates the physicochemical properties and bioactivities of plant polysaccharides. This study modified the Prunus cerasifera Ehrh. crude polysaccharide (PCCP) through sulfation, phosphorylation, acetylation, and carboxymethylation. The resulting derivatives were characterized using spectroscopic and chromatographic techniques. Antioxidant activities were evaluated through radical scavenging assays and reducing power tests, while hypoglycemic potential was assessed via α-glucosidase and α-amylase inhibition. The results indicated that all derivatives exhibited reduced uronic acid, protein content, and molecular weight. Each derivative consisted of heteropolysaccharides with varying molar ratios of rhamnose, arabinose, mannose, glucose, and galactose. Structural modifications significantly altered PCCP and its derivatives' morphology, crystallinity, and thermal properties. Biological activity studies revealed that different chemical modifications exerted distinct regulatory effects on the antioxidant and hypoglycemic capacities of PCCP. Among them, sulfation of PCCP (S-PCCP) demonstrated optimal performance in 2,2-diphenyl-1-picrylhydrazyl scavenging rate (86.8%), 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) scavenging rate (75.2%), and reducing power (76.42%), while phosphorylation of PCCP (P-PCCP) exhibited the highest hydroxyl radical scavenging capacity (82.3%). Moreover, S-PCCP exhibited significantly enhanced hypoglycemic activity, demonstrating half-maximal inhibitory concentrations of 1.91 and 1.94 mg/mL against α-glucosidase and α-amylase, respectively. This study confirms that chemical modification can directionally modulate the bioactivity of polysaccharides, providing a theoretical foundation for their potential application as antioxidant and hypoglycemic agents in the food industry.