R. Safari - PhD student
Z. Raftani Amiri - Associate Professor
R. Esmaeilzadeh Kenari - Associate Professor

In this study, the antibacterial and antioxidant properties of C-phycocyanin (C-PC) from Spirulina platensis were evaluated. The extraction and purification of C-PC were carried out using lyzosyme and ammonium sulphate precipitation, respectively. DPPH radical-scavenging activity, ferric reducing antioxidant power (FRAP) and Fe۲+-chelating activity were used for evaluation of antioxidant properties of C-PC. Antibacterial activity was also performed using agar well diffusion and microdilution [minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC)]. The selected bacteria were Escherichia coli, Staphylococcus aureus, Listeria monocytogenes, Streptococcus iniae and Yersinia ruckeri. The results showed that the biomass production was ۱۱۲۰ mg L-۱ and C-PC concentration in crude extracts and purified by (NH۴)۲SO۴ were also ۱.۸۱۵ and ۳.۷۵ mg ml-۱, respectively. The results of DPPH, FRAP and Fe۲+-chelating activities of C-PC was ۴۵.۷۵%, ۰.۰۵۱ mg TAE g-۱ and ۴۰.۲۳% at zero time and ۴۱.۵۶%, ۰.۰۴۶ mg TAE g-۱ and ۳۶.۵۶% after ۶۰ days at -۱۸°C, respectively. The results of agar well diffusion indicated that L. monocytogenes and S. iniae were the most sensitive and resistant, respectively among examined bacteria in different concentrations of C-PC (۰- ۲۵ µg ml-۱) and the mean of inhibition zones were also ۷.۵۰-۲۲.۱۱mm. The results of MIC and MBC of C-PC (as µg ml-۱) were ۵۰-۵۰۰ and ۱۰۰-۵۰۰, respectively. As a conclusion, C-PC from S. platensis had high potential of antioxidant activity in vitro and it can be used as natural antioxidants in variety of foods. Antibacterial activity of C-PC was lower than other algal pigments (such as astaxanthin and C-PC in other cyanobacteria).

Antibacterial properties, Antioxidant activity, C-phycocyanin, Spirulina platensis