Characterization, chemical modification and bioactivities of a polysaccharide from Stropharia rugosoannulata

This study evaluates the chemical structure of a heteropolysaccharide (SP-1a) from the fruiting bodies of Stropharia rugosoannulata and the antioxidant activity and enzyme inhibitory activity of its derivatives. The results showed that SP-1a (2.29 ×104 Da) contained fucose, glucose and galactose, and possessed the backbone of [→3)-α-D-Glcp-(1→] and [→3,6)-α-D-Glcp-(1→] with side chains [→6)-α-D-Galp-(1→] and T-α-D-Galp. Furthermore, carboxymethylated and phosphorylated modification of SP-1a (named as CSP-1a and PSP-1a) had good thermal stability and strong rehydration. Moreover, CSP-1a displayed stable DPPH scavenging ability (46.77%) and reducing power ability (0.434), as well as α-glucosidase inhibitory activity (60.98%) and α-amylase inhibitory activity (67.20%). Besides, PSP-1a presented significant hydroxyl radical scavenging ability (94.18%). The findings suggested that appropriate chemical modifications can improve the physicochemical properties and biological activities of polysaccharides from Stropharia rugosoannulata, providing hints and theoretical supports for further development of corresponding drug or food ingredients.