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 -Glc p -(1→] and [→3,6)-α- D -Glc p -(1→] with side chains [→6)-α- D -Gal p -(1→] and T-α- D -Gal p. 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. [Display omitted] • The structure of polysaccharide (SP-1a) from S. rugosoannulata was established. • SP-1a was carboxymethylated and phosphorylated successfully. • Carboxymethylated SP-1a showed stronger antioxidant and enzyme inhibitory activities. • Phosphorylated SP-1a presented significant hydroxyl radical scavenging ability. [ABSTRACT FROM AUTHOR]