Isofraxidin exhibited anti-inflammatory effects in vivo and inhibited TNF-α production in LPS-induced mouse peritoneal macrophages in vitro via the MAPK pathway

Isofraxidin (IF) is a Coumarin compound that can be isolated from medicinal plants, such as Sarcandra glabra (Thunb.). Nakai is widely used in Asian countries for the treatment of anti-bacterial, anti-inflammatory and anti-tumour action. The present investigation was designed to evaluate the effect of IF on inflammation and nociception. In addition, we investigated a potential novel mechanism to explain the anti-inflammatory properties of IF. In vivo, xylene-induced mouse ear edema, carrageenan-induced rat paw edema, LPS-induced mouse endotoxic shock, acetic acid-induced mice writhing and formalin-induced mouse pain models were used to evaluate the anti-inflammatory activity of IF. In vitro, we examined the effects of IF inhibition on TNF-α production and the regulation of ERK1/2 and p38 phosphorylation activity in LPS-induced mouse peritoneal macrophages. Our results demonstrated that IF can significantly decrease xylene-induced ear edema, carrageenan-induced paw edema, acetic acid-induced writhing and formalin-induced pain. Moreover, IF greatly inhibited the production of TNF-α in the serum of LPS-stimulated mice and peritoneal macrophages, and it decreased phospho-p38 and ERK1/2 protein expression in LPS-stimulated mouse peritoneal macrophages. Overall, our data suggest that IF possesses significant analgesic and anti-inflammatory activities that may be mediated through the regulation of pro-inflammatory cytokines, TNF-α and the phosphorylation of p38 and ERK1/2.