Antiinflammatory and analgesic effects of Eurycoma longifolia extracts

Eurycoma longifolia is one of the most popular herbal medicines in Southeast Asia. The purpose of this study is to evaluate the analgesic and anti-inflammatory effects of the methanolic extract of E. longifolia roots (TA) in vivo and to investigate the underlying mechanisms. TA was tested for analgesic activity by the hot plate test and acetic acid test in mice. The anti-inflammatory effect of TA was observed in carrageenan-induced paw edema in mice. The in vitro molecular study using macrophage cells was performed to elucidate the relevant mechanism. The analgesic activity of 400 mg/kg TA was higher than that of aspirin in the hot plate test. TA also showed analgesic effects in the acetic acid test in a dose-dependent manner. In carrageenan-induced edema in mice, TA showed an anti-inflammatory effect comparable to that of diclofenac. Further in vitro molecular study using macrophage cells revealed that TA suppressed NF-κB translocation to the nucleus, leading to inactivation of the NF-κB signaling pathway and reduction in the expression of cyclooxygenase-2 and inducible nitric oxide synthase. These results exhibited the beneficial effects of TA for alleviating pain and inflammation, which were exerted through inactivation of the NF-κB signaling pathway.