Anti-Fine Dust Effect of Fucoidan Extracted from Ecklonia maxima Leaves in Macrophages via Inhibiting Inflammatory Signaling Pathways

Abstract

Brown seaweeds contain fucoidan, which has numerous biological activities. Here, the anti-fine-dust activity of fucoidan extracted from Ecklonia maxima, an abundant brown seaweed from South Africa, was explored. Fourier transmittance infrared spectroscopy, high-performance anion-exchange chromatography with pulsed amperometric detection analysis of the monosaccharide content, and nuclear magnetic resonance were used for the structural characterization of the polysaccharides. The toll-like receptor (TLR)-mediated nuclear factor kappa B (NF-κB) and mitogen-activated protein kinase (MAPK) signaling pathways were evaluated. The results revealed that E. maxima purified leaf fucoidan fraction 7 (EMLF7), which contained the highest sulfate content, showed the best anti-inflammatory activity by attenuating the TLR-mediated NF-κB/MAPK protein expressions in the particulate matter-stimulated cells. This was solidified by the successful reduction of Prostaglandin E2, NO, and pro-inflammatory cytokines, such as TNF-α, IL-6, and IL-1β. The current findings confirm the anti-inflammatory activity of EMLF7, as well as the potential use of E. maxima as a low-cost fucoidan source due to its abundance. This suggests its further application as a functional ingredient in consumer products.

Relevance of the Extraction Stage on the Anti-Inflammatory Action of Fucoidans

“…Interestingly, the extracts with lower molecular weights showed strongest effects in this study, indicating an influence of molecular weight on the anti-inflammatory activity of fucoidans [ 86 ]. Nonetheless, Nagahawatta et al observed that fucoidans from Ecklonia maxima with similar molecular weights to those reported in the later study but higher sulfate contents than other extracts showed the best anti-inflammatory effect by attenuating TLR-mediated NF-κB/MAPK signaling [ 81 ].…”

“…These molecules play an important role in several cellular functions, but also up-regulate inflammatory responses inducing NF-κB activation and secretion of pro-inflammatory cytokines [ 78 , 79 ]. Several studies have reported that fucoidans isolated from brown seaweeds have the potential to inhibit MAPK phosphorylation [ 65 , 80 , 81 ]. Fucoidans obtained from Saccharina japonica demonstrated anti-inflammatory effects in vivo and in vitro in macrophages through the downregulation of MAPK expression (such as p38, ENK, and JNK) and NF-κB (such as p65 and IKKα/IKKβ) signaling pathways [ 33 ].…”

“…The sulfate content is one of the factors affecting fucoidan activity. Nagahawatta et al reported that a purified fucoidan fraction from Ecklonia maxima , selected for its high sulfate content, suppressed the production of NO, prostaglandin E2, and pro-inflammatory cytokines (TNF-α, IL-6, and IL-1β), by inhibiting the nuclear factor kappa B (NF-κB) and mitogen-activated protein kinase (MAPK) signaling pathways in particulate matter-stimulated RAW 264.7 cells [ 81 ]. An optimal sulfate content has been suggested [ 112 ].…”

In Vitro Anti-Inflammatory Activities of Fucoidans from Five Species of Brown Seaweeds

“…Purified fucoidan fraction from T. ornate down-regulated iNOS, COX-2, and pro-inflammatory cytokines, including PGE2 levels in RAW 264.7 macrophages [ 14 ]. Purified fucoidan from Ecklonia maxima (fucose content 81%) reduced prostaglandin E2, NO, and pro-inflammatory cytokines, such as TNF-α, IL-6, and IL-1β in macrophages [ 18 ]. A fucoidan from brown algae A. nodosum inhibited poly(I:C)-induced expression of some cytokines [ 51 ].…”

“…The inflammatory activity can be suppressed by inhibiting protein denaturation [ 14 ]. Although several anti-inflammatory mechanisms of fucoidan were reported [ 15 , 16 , 17 , 18 ], very little is known about the ability of fucoidans to prevent protein denaturation. Agents that can prevent protein denaturation would be worthwhile for anti-inflammatory drug development.…”