18β-Glycyrrhetinic acid (Enoxolone) is the major bioactive component of Glycyrrhizae Radix and possesses anti-ulcerative, anti-inflammatory and antiproliferative properties.

MTS assay demonstrates that 24 h treatment of Enoxolone suppresses cell proliferation in both cell lines in a dose-dependent manner. Enoxolone at 160 μM significantly decreases the percentage of viable cells to around 40.5±10.5% in A549 and 38.3±4.6% in NCI-H460 (p<0.01 respectively). When the cells are treated with 320 μM Enoxolone, a greater inhibitory effects on cell proliferation is shown, as the percentage of viable cells is below 30% compare with untreated controls (p<0.001). Treatment with Enoxolone at 160 μM and 320 μM decreases the levels of full-length PARP and increases the levels of cleaved-PARP.

Rats in Enoxolone+Triptolide (TP) group which receive low-dose Enoxolone (50?mg/kg) have significant reductions in the three serum parameters when compare with TP rats. Rats in Enoxolone+TP group which receive the high-dose Enoxolone (100?mg/kg) have slightly lowered the levels of three liver enzymes, the reductions do not reach statistical significance compare with TP group. Contrastingly, preadministration of low-dose Enoxolone protects animals from TP-induced hepatic lesions. On the contrary, low-dose Enoxolone (50?mg/kg) markedly suppresses the release of the four cytokines above.