Preparation, antioxidant and antimicrobial evaluation of hydroxamated degraded polysaccharides from Enteromorpha prolifera

In order to improve the antioxidant and antimicrobial abilities, hydroxamated degraded polysaccharides from Enteromorpha prolifera (HCDPE) were prepared from the corresponding carboxymethylated degraded polysaccharides (CDPE). HCDPE was characterized by FT-IR. The weight-average molecular weight of HCDPE was determined as 55.4   kDa. The in vitro antioxidant activity of HCDPE was evaluated by determining the radical (1,1-diphenyl-2-picrylhydrazyl (DPPH), hydroxyl and superoxide anion radicals) scavenging abilities and total antioxidant activity. It was found that DPPH radical scavenging ability and total antioxidant activity of HCDPE were significantly improved compared to those of CDPE. The inhibitory effects of polysaccharides against the five bacterial strains ( Bacillus subtilis , Staphylococcus aureus , Escherichia coli , Pseudomonas aeruginosa , Salmonella spp.) were also evaluated by bacterial inhibition zone and minimum inhibitory concentration (MIC) assays. The results indicated that CDPE and HCDPE possess marked antimicrobial ability, while such an effect was not observed for the crude polysaccharides (PE) and the degraded polysaccharides (DPE).