Antioxidant and iron-chelating activities of cyanobacterial exopolymers with potential for wound healing

Abstract

Progress of wound healing is critically dependent on the balance between oxidants and antioxidants at the wound site, and transition metals such as iron can exacerbate ROS generation. In the present study, cyanobacterial exopolymers from three strains of Anabaena and Tolypothrix tenuis have been characterized for their antiradical and Fe2+-chelating activity. All the four exopolymers exhibited antioxidant activities against O2·, H2O2, OH·, and NO·, with the exopolymer from Anabaena oryzae showing strong inhibition of NO· and ·OH radicals followed by that from Anabaena anomala. Correlation analysis of antioxidant activities and sulphate, uronic and phenolic content of the exopolymers showed a strong correlation of sulphate content to superoxide scavenging and activity against nitric oxide radicals. H2O2 scavenging was related to the presence of phenolics in the preparation which also contributed to the reducing power. Iron chelation had a strong bearing upon the overall reducing power and superoxide control.