FU Na, SHI Wenpan, LI Jingjie, LIN Yonggang, WANG Junlong
Based on the natural bioactivities of the polysaccharides from Armillaria luteo-virens polysaccharide (ALVP), the study was conducted to improve the antioxidant and hypoglycemic abilities of ALVP by carboxymethylation and selenylation modifications as raw materials.CM-ALVP and Se-ALVP were synthesized using the alkaline chloroacetic acid method and the sodium selenite method, respectively, from Armillaria luteo-virens polysaccharide (ALVP).The structural characteristics of the polysaccharides before and after modification were elucidated through spectroscopic and chromatographic analyses.The antioxidant and hypoglycemic capacities of the modified polysaccharides were evaluated by assessing their scavenging abilities against DPPH free radicals, ABTS cationic radicals, and hydroxyl radicals, as well as their Fe3+ reducing power.Additionally, their inhibitory effects on α-glucosidase and α-amylase were determined.Results indicated that all three polysaccharides were heteropolysaccharides composed of fucose, rhamnose, mannose, galactose, and glucose, exhibiting a pyranose structure.However, it was observed that the molar ratios of the monosaccharides changed following the modifications.Compared to ALVP, the modified polysaccharides CM-ALVP and Se-ALVP showed enhanced water solubility and thermal stability, with molecular weights increasing from 23.2 kDa to 23.3 kDa for both modifications.No changes were observed in the triple helical conformation or the phase structure.Fourier transform infrared spectroscopy revealed symmetric and asymmetric stretching vibrations of C=O groups at 1 617 cm-1 and 1 411 cm-1, respectively, and a characteristic absorption peak of SeO at 762 cm-1.Furthermore, nuclear magnetic resonance spectroscopy showed signal peaks at δ 4.46 ppm and δ 4.45 ppm, indicating successful carboxymethylation and selenylation modifications.The antioxidant and hypoglycemic activities demonstrated that, at a mass concentration of 8 mg/mL, the half-maximal inhibitory concentrations (IC50) of ALVP, CM-ALVP, and Se-ALVP against DPPH radicals were 3.05, 1.76, and 1.35 mg/mL, respectively, against ABTS radicals, the IC50 values were 5.72, 1.79, and 0.96 mg/mL, for hydroxyl radicals, the IC50 values were 4.00, 2.00, and 2.00 mg/mL, and the Fe3+ reducing capacities were 0.89, 0.96, and 1.05 AU, respectively.In terms of inhibitory rates against α-glucosidase, the values were 45.56%, 49.12%, and 54.11%, while the inhibitory rates against α-amylase were 42.44%, 48.77%, and 55.78%.These findings suggest that carboxymethylation and selenylation modifications can enhance the antioxidant and hypoglycemic activities of polysaccharides derived from yellow-green honey ring fungus.This study provides a theoretical foundation and data support for the further development and utilization of polysaccharides from Armillaria luteo-virens.