Glycoprotein from Sargassum fusiforme exhibiting anti-inflammatory responses in vitro and in vivo via modulation of TLR4/MyD88 and NF-κB signaling

This study focuses on the identification and characterization of a glycoprotein from Sargassum fusiforme (Harvey) Setchell (SFGP), as well as investigating its potential anti-inflammatory properties both in vitro and in vivo, along with the underlying mechanism. SDS-PAGE analysis revealed a prominent band with a molecular weight of <10 kDa, consisting of 58.39 % protein and 41.61 % carbohydrates, which was confirmed through glycoprotein staining and Coomassie blue staining. Various analytical techniques, including high-resolution mass spectrometry (HRMS), FTIR, amino acid analysis, and UV–visible spectrometry, provided evidence for the presence of monosaccharides (such as d-glucose and mannose) and 17 amino acids linked by an O-glycopeptide bond. In vitro and in vivo studies were conducted to assess the anti-inflammatory activities of SFGP. The results demonstrated that SFGP effectively attenuated nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expressions in LPS-treated RAW264.7 cells. Moreover, SFGP administration significantly and dose-dependently suppressed TLR4/MyD88 signaling as well as the phosphorylation of MAPKs, IκB, and NF-κB, leading to a reduction in the production of TNF-α, IL-1β, and IL-6 in LPS-stimulated RAW264.7 cells. Furthermore, the anti-inflammatory efficacy of SFGP was validated in a carrageenan-induced inflammatory mouse model. These findings indicate that SFGP exhibits anti-inflammatory characteristics and has the potential to be utilized as a novel anti-inflammatory agent.