Looking beyond Arthrospira: Comparison of antioxidant and anti-inflammatory properties of ten cyanobacteria strains

Abstract

Cyanobacteria are a widely distributed group of photosynthetic prokaryotes with potential to produce biologically active compounds. Arthrospira is the most widespread grown cyanobacteria for commercial purposes; however, many other species could be used as sources of a wide variety of bio-products. The pigment phycocyanin explains part of the therapeutic properties attributed to Arthrospira (e.g. antioxidant and anti-inflammatory). Many chronic diseases include, on its etiology, oxidative stress and abnormalities in the inflammatory response; thus, there is great interest in finding new sources of natural antioxidants and anti-inflammatory compounds. The aim of this work was to evaluate growth attributes, chemical composition and antioxidant and anti-inflammatory properties of ten cyanobacteria isolates. After 15 days of culture, biomass production ranged between 0.06 g/L (Anabaena) and 0.27 g/L (Phormidium) in 20 L volume cultures. Protein content of dry biomass ranged between 28.86 % (Nodularia) and 56.39 % (Arthrospira) while phycocyanin content ranged between 0.86 % (Nodularia) and 6.66 % (Spirulina). Aqueous extracts were evaluated regarding total phenolic content (TPC), total flavonoids content (TFC) and antioxidant activities (DPPH, ABTS and FRAP). Spirulina and Desertifilum exhibited the highest phenols and flavonoids contents; as well as the highest ABTS and FRAP antioxidant activities. Five strains were selected for measuring anti-inflammatory activity by the human erythrocyte membrane stabilization assay. All the strains evaluated exhibited a remarkable anti-inflammatory capacity, being the highest value for Desertifilum. Strains of Spirulina and Desertifilum were also tested for their ability to scavenge reactive oxygen species (ROS) on Hek293 cells; both strains showed significant intracellular antioxidant capacity and were not cytotoxic. This research demonstrated that other cyanobacterial strains, besides the popular Arthrospira, might be new sources of antioxidant and anti-inflammatory compounds for biotechnological applications in functional food, nutraceutical or pharmaceutical industries.