Extraction, structural characterisation, antioxidant, and hypoglycaemic activity of polysaccharides from Floccularia
Wei Feng1, Yuhao Cui1, Yaqi Tian1
1School of Chemistry and Chemical Engineering, University and College key Lab of Clean Conversion and High Value Utilization of Biomass Resources Key Laboratory of Resource Plant Protection and Utilization in the Ili River Valley, Yili Normal University, Yining, China.
Abstract:
This study systematically optimised the extraction process of Floccularia luteovirens polysaccharides (FLVP), establishing the optimal conditions as: power 400 W, temperature 52 °C, time 51 min, solid-liquid ratio 32:1 mL/g, and Ethylenediaminetetraacetic acid (EDTA) concentration 1.1 mg/mL. Three homogeneous polysaccharide fractions were isolated and purified: FLVP-I (124.327 kDa), FLVP-II (25.439 kDa), and FLVP-III (17.871 kDa). All three possess pyranose ring structures, with FLVP-I and FLVP-III containing both α- and β-glycosidic bonds, while FLVP-II exclusively contains α-glycosidic bonds. In antioxidant assays, FLVP-I exhibited the strongest activity, showing IC50 values of 0.27, 0.31, and 0.21 mg/mL against DPPH, ABTS+, and hydroxyl radicals, respectively, and restored the viability of H2O2-injured HepG2 cells to 87.42%. For hypoglycaemic activity, FLVP-II was most effective, with IC50 values of 0.29 and 0.22 mg/mL against α-amylase and α-glucosidase, respectively, and significantly promoted glucose consumption (8.02 mM) and hepatic glycogen synthesis (7.62 μg/mg protein) in insulin-resistant cells.
