Anti-inflammatory effects of sargachromenol-rich ethanolic extract of Myagropsis myagroides on lipopolysaccharide-stimulated BV-2 cells.

Excessive pro-inflammatory cytokine production from activated microglia contributes to neurodegenerative diseases, thus, microglial inactivation may delay the progress of neurodegeneration by attenuating the neuroinflammation. Among 5 selected brown algae, we found the highest antioxidant and anti-neuroinflammatory activities from Myagropsis myagroides ethanolic extract (MME) in lipopolysaccharide (LPS)-stimulated BV-2 cells. The levels of nitric oxide (NO), prostaglandin E2 (PGE2), and pro-inflammatory cytokines were measured by Griess assay and enzyme linked immunesorbent assay. The levels of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), mitogen-activated protein kinases (MAPKs), and Akt were measured using Western blot. Nuclear translocation and transcriptional activation of nuclear factor-κB (NF-κB) were determined by immunefluorescence and reporter gene assay, respectively. MME inhibited the expression of iNOS and COX-2 at mRNA and protein levels, resulting in reduction of NO and PGE2 production. As a result, pro-inflammatory cytokines were reduced by MME. MME also inhibited the activation and translocation of NF-κB by preventing inhibitor κB-α (IκB-α) degradation. Moreover, MME inhibited the phosphorylation of extracellular signal regulated kinases (ERKs) and c-Jun N-terminal kinases (JNKs). Main anti-inflammatory compound in MME was identified as sargachromenol by NMR spectroscopy. These results indicate that the anti-inflammatory effect of sargachromenol-rich MME on LPS-stimulated microglia is mainly regulated by the inhibition of IκB-α/NF-κB and ERK/JNK pathways.