IN VITRO ANTIOXIDANT ACTIVITY OF C-PHYCOCYANIN PURIFIED FROM Spirulina platensis DRY BIOMASS

C-phycocyanin (C-PC) was a phycobiliprotein found exclusively in cyanobacteria as Spirulina and exhibited a variety of pharmacological properties, which were not yet studied for any purpose in commercial applications in the pharmaceutical and cosmetic industry in Vietnam. At present, there are no other sources of natural phycocyanin than Spirulina, it is the sole efficient source of natural phycocyanin production under photoautotrophic conditions. The present research was conducted to determine an efficient extraction method from C-PC from Spirulina platensis dry biomass. Antioxidant activity of purified C-PC was investigated. Extractions were carried out using distilled water and Na-phosphate buffer pH 7.0 as solvents and freeze\thaw and ultrasonication techniques were applied to optimize the extraction process. Extraction using the freeze\thaw method proved to be the most efficient method. Phycocyanin purification from crude extracts was carried out by a combination of methods such as ammonium sulfate (NH4)2SO4 65% precipitation, dialysis filter, and Sephadex G-100 gel filtration chromatography, to give 121.63 ± 0.03 mg\g C-PC content and 3.52 ± 0.04 purity. Antioxidant activity in vitro was determined by nitric oxide (NO) scavenging activity, percentage inhibition of NO by the C-PC in concentration 10 μg\mL to 100 μg\mL which significantly scavenged 55.89% to 91.54% of NO radicals, respectively. They exhibited strong NO radical scavenging capacity, the C-PC and vitamin C were able to reduce the stable NO radical to 50% reduction with EC50 of 4.53 and 3.66 µg\mL. Research results showed that S. platenis dry biomass provided by Dalitra was potential for obtaining C-phycocyanin (12.16% of dry biomass) and it was evaluated as an antioxidant in vitro able to scavenge nitric oxide. C-PC (12.16% of dry biomass) and was evaluated as an antioxidant in vitro able to scavenge nitric oxide.