Antioxidant Activities of Phycocyanin: A Bioactive Compound from Spirulina platensis

Background and Objectives: The cyanobacterium Spirulina also called blue green algae is a class of gram negative bacteria which possesses wide range of bioactive colored components as Phycocyanin, carotenoids and chlorophyll. Spirulina is one of the microalgae containing nutrients that have been used as a functional food in addition to therapeutic and pharmaceutical applications. This study aimed to evaluate the biochemical composition of Spirulina platensis biomass and its ethanolic and aqueous extracts, as well as, evaluate the antioxidant activities of the biomass, ethanolic, aqueous and the purified Phycocyanin. Materials and Methods: The chemical compositions of Spirulina platensis were determined, as well as the antioxidant activity of extracts, Phycocyanin, Phycocyanopeptide and Phycocyanobilin using (DPPH) radical-scavenging activity. Results: Results show that biomass has higher total proteins (49.72±0.508%), total carbohydrates (10.3±0.330%), moisture content (7.5±0.685%), lipids (7.2±0.105%) and Minerals (6.9±0.130%). In biomass, the total phenols (51.20±0.25 µg/mL) and flavonoids (97.73±1.858 µg/mL) were high compared to the ethanolic (49.48±0.130 and 69.07±1.814 µg/mL) and aqueous (15.27±0.639 and 4.67±0.611 µg/mL) extracts respectively. In the phenolic compounds, pyrogallol was identified as the major compound in biomass and aqueous extract (63.85 and 12.33%) respectively, E-vanillic acid in ethanolic (18.20 %), whereas, hespirdin (3.517 and1.639%) were major flavonoids found in aqueous and ethanolic extracts respectively. The DPPH scavenging activity was found higher in ethanolic extract compared to aqueous while in bioactive, the order of antioxidant activity was Phycocyanin > Phycocyanobilin > Phycocyanopeptide. Conclusions: The study data regarding to Spirulina nutritional value, makes Spirulina an excellent choice when formulating diets and combating malnutrition. Furthermore, it is a strong antioxidant and could be used as alternative treatments as anticancer, antidiabetic, and anti-inflammatory agent.