Extraction, Purification, Structural Elucidation, and Antioxidant Assessment of the Bioactive Polysaccharides From Xinjiang Dried Apricot.

BACKGROUND

Xinjiang apricots (Prunus armeniaca L.) are rich in bioactive polysaccharides with antioxidant, anti-inflammatory, and immunomodulatory properties. As natural antioxidants, such polysaccharides offer advantages over synthetic counterparts in mitigating ROS-related diseases. Their antioxidant depends on structural features, yet Xinjiang apricot polysaccharides remain poorly characterized. This study employs ultrasound-assisted enzymatic extraction, DEAE-52 purification, and multitechnique structural analysis to investigate these polysaccharides, aiming to establish their structure-activity relationship for potential functional food or therapeutic applications.

RESULTS

In this study, a galacturonic acid-rich heteropolysaccharide (UEDAP-4) was successfully extracted and isolated from dried apricots from Xinjiang, China. The polysaccharide is primarily composed of five monosaccharides: arabinose (Ara), rhamnose (Rha), galactose (Gal), glucose (Glc), and galacturonic acid (GalA), with a molar ratio of 28.78:20.36:6.87:5.51:38.48. The main chain of UEDAP-4 is characterized by the following structure:⟶4)-α-D-GalpA-(1 ⟶ 5)-α-L-Araf-(1 ⟶ 4)-α-D-GalpA-(1 ⟶ 2)-α-L-Araf-(1 ⟶ 3)-α-L-Araf-(1 ⟶ 4)-α-D-GalpA-(1 ⟶ 2)-α-L-Rhap-(1 ⟶ 4)-α-L-Rhap-(1 ⟶ 4)-α-D-GalpA-(1⟶, with three additional branched chains. The half-maximal inhibitory concentrations (IC50) of UEDAP-4 against DPPH·, ·OH, and ABTS·+ were determined to be 5.399, 8.984, and 14.151 mg/mL, respectively. These results demonstrate that UEDAP-4 exhibits potent free radical scavenging activity, likely due to its high content of GalA and Ara.

CONCLUSIONS

This study significantly advances our understanding of the relationship between the structural properties of polysaccharides derived from Xinjiang dried apricots and their antioxidant activity. This discovery highlights UEDAP-4 as a promising candidate for natural antioxidants, with potential applications in food preservation, pharmaceutical formulations, and functional food development.