Antinflammatory effects of Tisochrysis lutea F&M-M36 and Arthrospira platensis F&M-C256 extracts

Functional foods offer, in addition to their high nutritional value, a health advantage due to the beneficial activities of their natural bioactive components. Several microalgae have been proposed as substrate for functional foods. In this study we evaluated the anti-inflammatory effects of the methanolic extract of Tisochrysis lutea F&M-M36 and the aqueous extract of Arthrospira platensis F&M-C256 by determining their inhibitory effects on pro-inflammatory mediators in lipopolysaccharide (LPS)-stimulated murine macrophage RAW cells. Their effects were compared to those of pure fucoxanthin (FX) and phycocyanin (PC). The expression of COX2, iNOs and heme oxygenase-1 (HO-1) genes was measured by RT-PCR in the cellular lysate and PGE2 concentration was quantified in the culture medium by using a competitive enzyme immunoassay. The methanolic extract from T. lutea F&M-M36 was able to reduce the LPS-stimulated production of PGE2, dose-dependently, exhibiting a higher effect compared to that of FX at a concentration comparable to that present in the microalgal biomass. On the contrary, only the water-soluble phycobiliprotein PC, modulated significantly the expression of the pro-inflammatory genes COX2 and iNOs. However, both extracts and single compounds up-regulated the expression of HO-1 in the presence of LPS, suggesting the involvement of the Nrf2/ARE signaling pathway that plays an important role in inhibiting the production of pro-inflammatory cytokines. In conclusion, these preliminary data indicate that T. lutea F&M-M36 and A. platensis F&M-C256 extracts inhibit inflammatory responses via the up-regulation of Nrf2/HO-1 pathway. These two microalgae have potential for the control of inflammatory chronic diseases.