Phloroglucinol possesses anti-inflammatory activities by regulating AMPK/Nrf2/HO-1 signaling pathway in LPS-stimulated RAW264.7 murine macrophages

Background: Inflammation is closely related to the pathogenesis of chronic illnesses. Secondary metabolites of marine seaweeds are recognized as reliable sources of bioactive compounds due to their health benefits besides their nutritional value. The objective of this study was to determine the potential anti-inflammatory effect of phloroglucinol (Phl) in RAW264.7 murine macrophages after lipopolysaccharides (LPS) stimulation. Methods: MTT, nitric oxide (NO), and DCFH-DA assays were conducted to determine cell viability, NO production, and reactive oxygen species (ROS) generation respectively. Pro-inflammatory cytokines and prostaglandin E-2 (PGE(2)) levels were measured using ELISA assay kits. Protein expression levels were determined by western blot analysis. Results: Phl treatment showed a promising anti-inflammatory effect by reducing NO production, secretion of pro-inflammatory cytokines (TNF-alpha, IL-1 beta, and IL-6), PGE2 production, protein expression levels of inducible nitric oxide synthase (iNOS), and cyclooxygenase-2 (COX-2), and ROS generation in LPS-stimulated RAW264.7 murine macrophages. Phl treatment upregulated heme oxygenase-1 (HO-1) expression by inducing nuclear translocation of nuclear factor erythroid 2-related factor 2 (Nrf2) and activating AMPK. However, Zinc protoporphyrin (ZnPP), an inhibitor of HO-1, partially reversed these effects, including NO production, pro-inflammatory cytokine secretion, iNOS, COX-2 and HO-1 expression, and ROS generation. Conclusion: Phl has potential anti-inflammatory activities by regulating AMPK/Nrf2/HO-1 pathway in LPS-stimulated RAW264.7 murine macrophages.

Automated summary

This study found that phloroglucinol, a secondary metabolite of marine seaweeds, has potential anti-inflammatory effects by inhibiting oxidative stress, reducing pro-inflammatory cytokine secretion and prostaglandin production in LPS-stimulated RAW264.7 macrophages. These effects may be mediated through the activation of the AMPK/Nrf2/HO-1 pathway.