Synthesis, characterization, and evaluation of microwave-assisted fabricated selenylation Astragalus polysaccharides

Selenylation Astragalus polysaccharides (Se-APS) was fabricated by an optimized microwave-assisted method. Their physicochemical properties, antioxidant capacities and selenium (Se) release rate under gastrointestinal conditions were determined. Se-APS with the highest Se content (18.8 mg/g) was prepared in 0.4 % nitric under the microwave conditions of 90 min and 80 ?. FTIR and XPS spectra indicated that Se was bound to polysaccharide chain in the form of O-Se-O and O-H...Se, and most of Se+4 was reduced to Se-0. Meanwhile, micromorphology of Se-APS became clusters, loose and porous, which decreased its hydrodynamic particle and negative surface charges. Besides, Se-APS displayed strong scavenging capacities towards ABTS and superoxide anion free radicals than Na2SeO3, and showed higher Se release rate (12.52 & PLUSMN; 0.31 %) under intestinal fluid comparing with gastric fluid (3.14 & PLUSMN; 0.38 %) during 8 h in vitro digestion. The results provided efficient preparation method references for selenylation polysaccharides, and broaden the application fields of APS.

Automated summary

Selenylation Astragalus polysaccharides (Se-APS) were successfully prepared using an optimized microwave-assisted method. The Se-APS exhibited high selenium content and showed improved antioxidant capacities compared to Na2SeO3. The release of selenium from Se-APS was higher in intestinal fluid than in gastric fluid.