Preparation, characterization and evaluation of microwave-assisted synthesized selenylation Codonopsis pilosula...

In this work, the selenylation Codonopsis pilosula polysaccharide (Se-CPPS) were synthesized using an optimized microwave-assisted method. Then, physicochemical properties, including molecular weight, particle size, valence state of selenium, antioxidant capacity, release mechanism of selenium under gastrointestinal conditions, as well as their effects on HT-29 cell viability were comprehensively investigated. The results demonstrated that Se-CPPS with the highest selenium content (21.71 mg/g) was synthesized using 0.8% nitric acid concentration under microwave conditions of 90 min at 70 °C. FTIR and XPS analysis revealed that Se was bound to the polysaccharide chain in the form of O-Se-O and O-H···Se, with a valence state of either 0 or +4. In vitro investigations on antioxidant activity and selenium release capacity indicated that selenization not only enhanced the antioxidant activity of CPPS but also endowed Se-CPPS with robust selenium release capability in simulated gastric digestion. The effects of Se-CPPS on HT-29 cells was further investigated by CCK-8 method. The results showed that the selenide modification effectively reduced the toxicity of Na₂SeO₃ and enhanced the viability of CPPS. The findings of this study offer valuable methodological guidance for the synthesis of Se-polysaccharides with superior functional properties.