Nodakenetin Alleviates Inflammatory Pain Hypersensitivity by Suppressing NF-κB Signal Pathway

<b><i>Background:</i></b> Inflammatory pain mediated by nuclear factor kappa-B (NF-κB) signal pathway has become an increasingly important clinical issue in the last decade. As a potent antioxidant, Nodakenetin has been shown to have a prominent inhibitory effect on inflammation. However, the therapeutic effects and underlying pharmacological mechanisms of Nodakenetin for inflammatory pain remain unclear. <b><i>Methods:</i></b> Intraplanar injection of complete Freund’s adjuvant (CFA) was used to establish a model of chronic inflammation pain in C57BL/6 mice. The chronic neuropathic pain model was conducted by the sciatic nerve ligation surgery. QRT-PCR was performed to estimate the RNA levels of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6). Western blot was used to demonstrated the protein levels of phospho-IkappaBα (IκBα), p50, and p65 in HEK293T cells. <b><i>Results:</i></b> The bioactive components of the traditional Chinese medicine Notopterygium forbesii boiss mainly include Nodakenetin, isoimperatorin, and pregnenolone. Nodakenetin significantly alleviated CFA-induced inflammatory pain but showed no significant therapeutic effect on surgically induced neuralgia in a mouse model. In contrast, isoimperatorin and pregnenolone did not relieve CFA-induced inflammatory pain. Mechanistically, Nodakenetin inhibited IL-1β-induced activation of the NF-κB pathway and phosphorylation of IκBα in HEK293T cells. Furthermore, Nodakenetin treatment suppressed the expression of IL-6, TNF-α, and IL-1β in mouse bone marrow-derived macrophages. <b><i>Conclusion:</i></b> Nodakenetin alleviates inflammatory pain induced by CFA injection in vivo and modulates NF-κB signal pathway in vitro.