Bioactive compounds from Sargassum horneri attenuates inflammation and obesity regulating by Nrf2/HO-1 and AMPK signaling pathways.

Sargassum horneri is rich in bioactive compounds, including phytosterols, exhibits antioxidant, anti-obesity and anti-inflammation properties; however, its underlying mechanisms remain unclear. In this study, we evaluated that the antioxidant and anti-inflammatory effect of S. horneri ethanolic extract and its subfractions using lipopolysaccharide (LPS)-treated RAW264.7 cells. Furthermore, we examined the in vivo anti-obesity efficacy of S. horneri using obese mice fed a high-fat diet. Results revealed that the in vitro treatment increases the inflammatory cytokines such as inducible nitric oxide synthase (iNOS), nitric oxide (NO), cyclooxygenase-2 (COX-2), prostaglandin E2 (PGE(2)), tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) including nuclear factor kappa B (NF-κB) subunit p65 protein expressions in LPS treated RAW264.7 cells. However, these pro-inflammatory cytokines were significantly reduced by inhibiting the NF-κB- p65 translocation pathway in S. horneri treatment. In addition, the S. horneri extracts increased the nuclear factor erythroid 2-related factor 2 (Nrf2) translocation into the nucleus as well as their heme oxygenase (HO-1) target gene expression. Whereas, in vivo treatment with S. horneri reduces body and organ weight, including pathological damage in liver and adipose tissue. Moreover, S. horneri decreases serum triglycerides (TG), LDL-cholesterol, total cholesterol (TC), arteriosclerosis index (AI), and cardiovascular risk factor (CVRF), but increases HDL-cholesterol concentration-dependently. The liver antioxidant enzyme activities and AMP-activated protein kinase (AMPK) protein expressions were raised in S. horneri treated groups; while sterol regulatory element-binding protein-1 (SREBP-1), Fatty acid synthase (FAS), and Acetyl-CoA carboxylase (ACC) expressions was reduced with dose-dependent manner. These findings provide an innovative pharmacological basis for the antioxidant, anti-inflammatory and anti-obesity effect of S. horneri. It specifies the potential of S. horneri as a candidate for preventing inflammation, obesity and other related disorders.