Inhibitory effects of flavonoids on TNF-α-induced IL-8 gene expression in HEK 293 cells

Due to their multiple biological activities, flavonoids have gained attention as potentially useful therapeutics for a variety of diseases including cancer, cardiovascular diseases, and autoimmune diseases. In this study, we demonstrated that several flavonoids, including kaempferol, quercetin, fisetin, and chrysin block TNF-alpha induced IL-8 promoter activation and gene expression in HEK 293 cells. In addition, phosphorylation and degradation of IkappaBalpha and translocation of NF-kappaB p65 were inhibited by these flavonoids in TNF-alpha-stimulated HEK 293 cells. Furthermore, generation of reactive oxygen species (ROS) in response to TNF-alpha was reduced by the flavonoids. Moreover, although pretreatment with fisetin, quercetin, or chrysin decreased cell viability, kaempferol did not. Taken together, these findings suggest that kaempferol would be useful for the treatment of TNF-alpha-induced inflammatory diseases.