Characterization of carboxymethylated polysaccharides from Catathelasma ventricosum and their antioxidant and antibacterial activities

Abstract The mycelial polysaccharides from Catathelasma ventricosum (mCVP-1Ss) were modified by carboxymethylation with different reaction conditions (reaction time, temperature and chloroacetic acid dosage) to obtain carboxymethylated mCVP-1Ss (cmCVP-1Ss), and their primary structures were characterized. NMR results indicated that substitution of carboxylate groups appeared primarily at C-6 position. Carboxymethylation significantly improved the antioxidant and antibacterial activities of mCVP-1S, while cmCVP-1Ss with medium degree of substitution (DS) and stable triple-helical structurepossessed the greatest DPPH radical scavenging activity, reducing power, metal chelating activity andantibacterial activity. When the concentration of cmCVP-1S3/8/13 reached 7.5 mg/mL, it showed excellent inhibitory effect on Escherichia coli, Salmonella Typhimurium, Staphylococcus aureus and Bacillus subtilis. However, excessive DS might destroy the triple helical structure of cmCVP-1S, thus significantly weaken the biological activities of cmCVP-1S·cmCVP-1Ss possess excellent antioxidant and antibacterial activities and have potential to be used as new types of antioxidant and antibiotic, which are inartificial and safer.