Andrographolide attenuates tumor necrosis factor-alpha-induced insulin resistance in 3T3-L1 adipocytes

Andrographolide (AG), the primary bioactive component of Andrographils paniculate Nees, has showed an anti-diabetic effect. However, the molecular mechanism has not been clarified. In this study, we demonstrated that AG increased glucose uptake in 3T3-L1 cells in a time- and dosedependent manner. The activation of insulin signaling by AG was initiated from phosphotyrosine of IRS-1 and further passed on through phosphatidylinositol 3-kinase (PI3K) and the downstream signaling cascades. Moreover importantly, pretreatment cells with AG suppressed the TNF-α induced activation of NF-κB signaling pathway and its downstream inflammatory factors expression, therefore ameliorating insulin resistance. In conclusion, AG can improve insulin sensitivity through inhibition of NF-κB pathway. These findings are helpful in understanding the anti-diabetic properties of AG and can be of interest for the therapeutic application of AG in glucose controlling.