TNF-α production inhibitory activity of Scorzonera species. The cells were pretreated with extracts 1–8 (Ex. 1–8) (25 μg/mL), and prednisone (1 µM), or the vehicle (Veh., DMSO) only. After 1 h of the incubation, the inflammatory response was induced by LPS [except of the control cells (CTRL)]. The secretion of TNF-α was measured 24 h after the LPS addition. The results are expressed as mean ± SE for three independent experiments. * Significant difference in comparison to vehicle only treated cells (p < 0.05), ** significant difference in comparison to vehicle only treated cells (p < 0.01), *** significant difference in comparison to vehicle only treated cells (p < 0.001).