Anti-Inflammatory Activity of Cyanobacteria Pigment Extracts: Physiological Free Radical Scavenging and Modulation of iNOS and LOX Activity.

Cyanobacteria are among the oldest organisms colonizing Earth. Their great biodiversity and ability to biosynthesize secondary metabolites through a variety of routes makes them attractive resources for biotechnological applications and drug discovery. In this pioneer study, four filamentous cyanobacteria ( LEGE 15493, LEGE 15486, LEGE 06104 and sp. LEGE 11479) were explored for their anti-inflammatory potential in cell and cell-free in vitro bioassays, involving different inflammatory mediators and enzymes. Extracts of different polarities were sequentially prepared and chemically characterized for their content of phycobiliproteins (PBPs) and carotenoids. HPLC-PDA analysis of the acetone extracts revealed β-carotene to be the dominant carotenoid (18.4-44.3 mg/g) and zeaxanthin as the dominant xanthophyll (52.7-192.9 mg/g), with sp. LEGE 11479 and LEGE 06104, respectively, being the richest strains. The PBP profile was in accordance with the color presented by the aqueous extracts, with LEGE 15486 being the richest in phycocyanin (204.5 μg/mg) and sp. LEGE 11479 the richest in phycoerythrin (78.5 μg/mg). Aqueous extracts were more effective in superoxide anion radical scavenging, while acetone ones were more effective in scavenging nitric oxide radical (NO) and in inhibiting lipoxygenase. Acetone extracts also reduced NO production in lipopolysaccharide-stimulated RAW 264.7 macrophages, with the mechanistic study suggesting a downregulation of the inducible nitric oxide synthase expression. LEGE 06104 and sp. LEGE 11479 acetone extracts presented the lowest IC values for the mentioned assays, pointing them out as promising resources for the development of new multi-target anti-inflammatory therapies.