Vitex trifolia L. modulates inflammatory mediators via down-regulation of the NF-κB signaling pathway in carrageenan-induced acute inflammation in experimental rats

Vitex trifolia L. (V. trifolia L.), commonly known as the three-leaved chaste tree, is extensively employed in traditional Chinese medicine (TCM) to treat various conditions associated with inflammation. The present study aimed to delineate the molecular mechanisms responsible for the anti-inflammatory effect of V. trifolia L. in carrageenan (CA)-induced acute inflammation in experimental rats. CA-induced rat paw edema model was adopted to investigate the anti-inflammatory effect of methanolic extract from leaves of V. trifolia L. (VTME) in vivo. Leukocyte infiltration into the site of inflammation was determined by histopathological analysis. Further, the effect of VTME on CA-induced local and systemic levels of specific cytokines was quantified by enzyme-linked immunosorbent assay (ELISA). Moreover, its impact on the nuclear translocation of nuclear factor Kappa B (NF-κB) was analyzed by employing the western blotting technique. VTME at the doses of 100 mg/kg and 200 mg/kg significantly inhibited the paw edema induced by CA (p < 0.05) and effectively reduced the inflammatory leukocyte infiltration. Further, VTME markedly inhibited the CA-induced levels of Interleukin (IL)-1β, IL-6, tumor necrosis factor (TNF)-α in tissue, and that of cytokine-induced neutrophil chemoattractant (CINC)-2/C-X-C motif chemokine (CXCL)3 and CINC-3/CXCL2 in tissue as well as in serum. On the other hand, VTME significantly upregulated the tissue concentration of anti-inflammatory cytokine IL-10. Moreover, VTME significantly attenuated the CA-induced IκBα degradation and nuclear translocation of NF-κB p65. Our results demonstrate the potent anti-inflammatory effect of V. trifolia L. in vivo, providing insight into its molecular mechanism, which is mediated through down-regulation of NF-κB signal transduction.