Preparation, characterization and bioactivities of selenized polysaccharides from Lonicera caerulea L. fruits

Native polysaccharide was obtained from Lonicera caerulea L. fruits (PLP). Two selenized polysaccharides (PSLP-1 and PSLP-2) were synthesized by the microwave-assisted HNO₃-Na₂SeO₃ method, where the selenium (Se) contents were 228 ± 24 and 353 ± 36 μg/g, respectively. The molecular weights of PLP, PSLP-1, and PSLP-2 were 5.9 × 10⁴, 5.6 × 10⁴, and 5.1 × 10⁴ kDa, respectively. PSLP-1 and PSLP-2 contained the same type of monosaccharides as PLP but with different molar ratios. The main chain structure of the native polysaccharide was not changed after selenization. PLP, PSLP-1, and PSLP-2 contained the same six types of glycosidic bonds. Bioactivity assays revealed that the two selenized polysaccharides possessed better antioxidant activities than PLP, but their bile acid-binding abilities and inhibitory activities on acetylcholinesterase (AChE) had weakened. In summary, PLP, PSLP-1, and PSLP-2 may be promising Se supplements in functional foods and inhibitors for the treatment of AChE.