Cysteine rich cyanopeptide β2 from Spirulina fussiformis exhibits plasmid DNA pBR322 scission prevention and cellular antioxidant activity.

Isolation of three different active peptides from C-phycocyanin (C-pc) β chain of S. fussiformis and their biological properties are reported. Phycocyanin peptide β fraction 2 (cyanopeptide β 2) facilitated both antioxidant and plasmid DNA strand scission prevention activity due to higher cysteine moieties in the isolated peptide. The peptide significantly scavenged the free radicals like 1-1,-diphenyl-2-picryl hydrazyl and ferric reducing ability of plasma, increased the absorbance values in reducing power and also showed the higher trolox equivalent antioxidant capacity values in total reactive antioxidant potentials assay. Cyanopeptide β 2 also inhibited reactive oxygen species induced DNA pBR322 damage in dose dependent manner along with free radical scavenging properties suggesting the role in the DNA integrity which is also evident by DNA binding activity of peptide. In addition, the generation of reactive oxygen species (ROS) was dose dependent (10 and 20 ng/ml) and significantly quenched by cyanopeptide β2 in human fibroblast cell line TIG 3-20. In vitro cell scratch injury assay demonstrated the capacity of cyanopeptide β2 in cell migration in to wounded area suggesting fibroblast proliferation and migration. The results suggest that cyanopeptide β2 can be a free radical scavenger and effective peptide for future biomedical applications like wound healing, atherosclerosis, cell redox potential and hypoxia.