Bioactive properties of Spirulina-derived phycobiliproteins and phycobilins

Abstract

Arthrospira (Spirulina), photosynthetic, filamentous cyanobacteria, has been used as food for centuries. It is one of the richest known natural source of proteins and essential amino acids, an excellent source of vitamins, macro-and micro-elements, pigments, essential fatty acids, glycolipids, and polysaccharides. C-phycocyanin (C-PC), the most abundant protein of Spirulina, is a highly fluorescent and water-soluble heterodimeric phycobiliprotein. Its blue colour arises from covalently attached (via thioether bond) tetrapyrrole chromophore phycocyanobilin (PCB). Numerous studies have shown C-PC exhibit significant anti-inflammatory, immunomodulatory and anticancer effects which could be ascribed to the powerful anti-oxidative activities of PCB. Indeed, studying the digestion of C-PC in simulated gastrointestinal conditions revealed that obtained chromopeptides possess significant anticancer, anti-oxidative and metal-binding properties. Furthermore, it has been shown that various proteins (human and bovine serum albumins, bovine catalase, bovine lactoglobulin) can bind PCB, which could influence pharmacokinetic behaviour, bioavailability and oxidative stability PCB. On the other hand, the presence of tetrapyrrole chromophore increases the thermal, oxidative and digestion stability of these proteins. This work reviews the recent findings of bioavailability, distribution and bioactive properties of C-PC and its chromophore, which could be of fundamental significance and applicative potential.