Anti-inflammatory effects of TP1 in LPS-induced Raw264.7 macrophages

Inflammation is an essential defense mechanism in health; however, excessive inflammation contributes to the pathophysiology of several chronic diseases. Although anti-inflammatory drugs are essential for controlling inflammation, they have several side effects. Recent findings suggest that naturally derived compounds possess physiological activities, including anti-inflammatory, antifungal, antiviral, anticancer, and immunomodulatory activities. Therefore, this study aimed to investigate the anti-inflammatory effects and molecular mechanisms of 2,5,6-trimethoxy-p-terphenyl (TP1), extracted from the Antarctic lichen Stereocaulon alpinum, using in vitro models. TP1 treatment decreased the production of nitric oxide (NO) and reactive oxygen species (ROS) in LPS-stimulated Raw264.7 macrophages. Additionally, TP1 treatment significantly decreased the mRNA levels of pro-inflammatory cytokines (IL-1β, TNF-α, IL-6) and the mRNA and protein levels of the pro-inflammatory enzymes (inducible nitric oxide synthase and cyclooxygenase-2). Moreover, TP1 suppressed lipopolysaccharide-induced phosphorylation of the NF-κB and MAPK signaling pathways in Raw264.7 macrophages. Conclusively, these results suggest that TP1 ameliorates inflammation by suppressing the expression of pro-inflammatory cytokines, making it a potential anti-inflammatory drug for the treatment of severe inflammatory diseases.