Extraction, purification, characterization, and α-amylase inhibition of C- Phycocyanin from Dolichospermum spiroides

Abstract

Abstract Phycocyanin is a phycobiliprotein pigment synthesized by cyanobacteria to protect the light-harvesting complex from the high intensity of light during photosynthesis. Intriguingly, it has a wide range of biotechnological applications such as pharmaceuticals, cosmeceuticals, and food-grade pigments based on their purity. Phycocyanin is a highly antioxidant water-soluble pigment with anticancer, anti-inflammatory, hepatoprotective, and neuroprotective properties. Phycocyanin from Spirulina (Arthrospira platensis) has been reported to possess antidiabetic activity by inhibiting the α-amylase enzyme both in vitro and in vivo. In our present study, C-phycocyanin was extracted and purified from the cyanobacterium Dolichospermum spiroides with a purity of 1.2, and 3.5 after column chromatographic purification with a molecular weight of 16 kDa. Based on protein mass fingerprinting, it has about 45% amino acid sequence similarity with the C-PC of Aphanizomenon flos-aquae. The C-PC of D. spiroides has a maximum inhibition of 90% at 250 µg/mL of α-amylase enzyme. At the same concentration of the standard drug acarbose, which attained only 80% of α-amylase inhibition. As a result, the IC50 value of C-PC from D. spiroides was 162.16 ± 0.63 µg/mL, and acarbose was 205.86 ± 0.53 µg/mL. Therefore, the alpha-amylase inhibition of phycocyanin was higher than that of the standard drug acarbose. Hence, it is clear that the C-PC of D. spiroides has anti-diabetic activity.