C-phycocyanin from Spirulina fussiformis exposed to blue light demonstrates higher efficacy of in vitro antioxidant activity

In this study we made the comparative evaluation of antioxidant activities of C-phycocyanins produced from Spirulina fussiformis exposed to blue light (C-pc (B)) and normal light (C-pc (N)), by various antioxidant assays such as 2,2-azino-bis(3)ethylbenzthiazoline-6-sulfonic acid (ABTS), 1,1-diphenyl-2-picrylhydrazyl (DPPH), super oxide anion (O2−) scavenging, hydroxy radical (OH) scavenging, hypochlorous acid (HOCl) scavenging, ferrous oxidation xylenol orange (FOX), oxygen radical absorbance capacity (ORAC), ferric reducing ability of plasma (FRAP) and reducing power assays. The observed antioxidant activities were compared with that of ascorbic acid, a standard antioxidant. C-pc (B) exhibited significantly (p < 0.05) higher radical scavenging effect than in DPPH, OH, HOCl, ORAC and FRAP assay conditions in a dose-dependent manner. Higher reducing power of C-pc (B) demonstrated a dose-dependent pattern and indicated the presence of free radical scavenger moieties. Furthermore, sequencing of α and β chains of both C-pcs revealed marginal changes in α chains of both kinds of C-pcs and realignment of sequences from 76 to 97 amino position in β chain of C-pc (B) indicating modification of the polypeptide with higher cysteine. In conclusion the present study demonstrated that C-pc (B) showed higher antioxidant activity.