Abstract: Prunella vulgaris polysaccharides (PVPs) were extracted by using ultrasonication extraction,  and polysaccharide component (PVP-2) was isolated and purified from PVPs. Physicochemical characteristics,  antioxidant,  hypoglycemic and antibacterial activities of PVP-2 and derivatives (Zn-PVP-2,Se-PVP-2,S-PVP-2 and P-PVP-2) modified by zinc,  selenium,  sulfonation and phosphorylation were compared. The results show that compared with natural PVP-2,  the contents of uronic acid,  total phenol,  total flavonoids,  sulfuric acid group,  glucuronic acid and galacturonic acid,  water solubility,  antioxidant,  hypoglycemic and antibacterial activities of the derivatives are significantly increased,  but the relative molecular weight and protein content are decreased. The modification leads to the degradation of the neutral side chains of PVPs,  and significantly changes the molar ratio of monosaccharides,  but does not change the backbone structure of PVP-2. P-PVP-2 has the highest antioxidant activity and hypoglycemic activity,  and Se-PVP-2 has the best antibacterial activity,  indicating that the chemical modification methods are effective in the modification of PVP-2, and chemical modification can enhance the potential application of PVPs in the food and pharmaceutical industries.

Key words: Prunella vulgaris polysaccharide,  , modification,  , physicochemical characteristics, bioactivity