Anti‐inflammatory and peroxisome proliferator‐activated receptors (PPARs) transactivational effects of nine compounds (1 − 9) from the roots of Sophora flavescens were evaluated using NF‐κB‐luciferase, reverse transcriptase polymerase chain reaction, peroxisome proliferator response element (PPRE)‐luciferase, and GAL‐4‐PPAR chimera assays. Compounds 4 and 8 significantly inhibited TNFα‐induced NF‐κB transcriptional activity in HepG2 cells in a dose‐dependent manner, with IC₅₀ values of 4.0 and 4.4 μM, respectively. Furthermore, the transcriptional inhibitory function of these compounds was confirmed by a decrease in cyclooxgenase 2 and inducible nitric oxide synthase gene expression levels in HepG2 cells. Compounds 1, 3, 5, 6, 8, and 9 significantly activated the transcription of PPARs in a dose‐dependent manner, with EC₅₀ values ranging from 1.1 to 13.0 μM. Compounds 1, 3, 5, 6, 8, and 9 exhibited dose‐dependent PPARα transactivational activity, with EC₅₀ values in a range of 0.9 − 16.0 μM. Compounds 1, 3, 8, and 9 also significantly upregulated PPARγ activity in a dose‐dependent manner, with EC₅₀ values of 10.5, 6.6, 15.7, and 1.6 μM, whereas compounds 1, 8, and 9 demonstrated transactivational PPARβ(δ) effects with EC₅₀ values of 11.4, 10.3, and 1.5 μM, respectively. These results provide a scientific rationale for the use of the roots of S. flavescens and warrant further studies to develop new agents for the prevention and treatment of inflammatory and metabolic diseases. Copyright © 2012 John Wiley & Sons, Ltd.