C-Phycocyanin from Oscillatoria tenuis exhibited an antioxidant and in vitro antiproliferative activity through induction of apoptosis and G0/G1 cell cycle arrest.

This study was undertaken to develop an efficient single step chromatographic method for purification of C-phycocyanin (CPC) from species of Oscillatoria tenuis. Purification of CPC involves a multistep treatment of the crude extract by precipitation with ammonium sulphate, followed by gel filtration chromatography. Pure CPC was finally obtained from O. tenuis with purity ratio (A620/A280) 4.88. SDS-PAGE of pure CPC yielded two bands corresponding to α and β subunits; the molecular weight of α subunit is 17.0 kDa, whereas the molecular weight of β subunit is 19.5 kDa. Fluorescence and phase contrast microscopy revealed characteristic apoptotic features like cell shrinkage, membrane blebbing, nuclear condensation and DNA fragmentation. CPC exhibited antioxidant and antiproliferative activity against human cancer cells through apoptosis; nuclear apoptosis induction was accompanied by G0/G1 phase arrest and DNA fragmentation. CPC is a natural pigment with potential as an anticancer agent.