Antioxidant activity, α-amylase and α-glucosidase inhibition properties of sulfated-polysaccharides purified from freshwater plant Myriophyllum spicatum L.

Sulfated polysaccharides presenting in the cell wall of seaweeds and aquatic plants exhibit a diverse range of biological functions mainly due to their particular structural and molecular properties. The aim of the current study was to evaluate the inhibition of oxidation reactions and activities of digestive enzymes including α-amylase and α-glucosidase by sulfated polysaccharides from aquatic plant Myriophyllum spicatum. After the removal of pigments and low molecular weight compounds, polysaccharides were extracted by distilled water at 60°C for 2 hours. Polysaccharide purification using DEAE Sepharose FF led to production of two fractions including F1 and F2. Obtained polysaccharides were considerably capable of scavenging DPPH free radicals (20.62-64.81%) and reducing Fe3+ ions (0.24-0.50 Abs) with F1 fraction exhibiting the greatest activity. Polysaccharides inhibitions against α-amylase activity were greatly different (22.50-63.20%) with the lowest IC50 being 1.31 mg/mL for F2 fraction. α-glucosidase activity was reduced to various levels (1.30-89.5%) and the lowest IC50 of 10.0 mg/mL was observed for crude polysaccharide. Overall, these findings indicated that sulfated polysaccharides from M. spicatum L. possess promising antioxidant, α-amylase and α-glucosidase inhibition potentials depending on their chemical and molecular structure and thus could be considered as antioxidant and anti-diabetic agents.