Abstract: Objective To investigate the effects of isoliquiritigenin on the invasive ability of human gastric carcinoma SGC7901 cells, and its molecular mechanisms thereof. Methods The logarithmic phase human gastric carcinoma SGC7901 cells were divided into control group (normal cell culture fluid) and isoliquiritigenin group (isoliquiritigenin soluble in cell culture fluid, the concentrations were 10, 25, 50 and 100 μmol/L respectively). Each group had four repeated holes. The proliferation of SGC7901 cells were detected with MTT assay after 24 h, 48 h and 72 h of culture. The experimental drug concentration and action time were researched for the subsequent experiments. The in vitro invasion abilities of SGC7901 cells were assessed with Transwell test. The expression levels of MMP9, Akt and P-Akt were detected by Western blot assay. Results The proliferation of SGC7901 cells were inhibited by 10 μmol/L isoliquiritigenin, which can be significantly inhibited by 25, 50 and 100 μmol/L isoliquiritigenin in a concentration-dependent and time-dependent manner. The half inhibitory concentrations (IC50) of 24, 48 and 72 h were 52.48, 44.49 and 32.50 μmol/L, respectively. Therefore, the 25, 50 and 100 μmol/L isoliquiritigenin were selected as the subsequent experimental drug concentration, and 24 h was used as the action time. Compared with the control group (209.75±9.29), the membrane cell number of 25 μmol/L (138.50±10.15), 50 μmol/L (89.50±16.56) and 100 μmol/L (45.00±8.08) decreased gradually (F=267.948， P < 0.05). There was no significant difference in the expression level of Akt protein between four groups (F=1.492). The expression levels of P-Akt and MMP9 were gradually decreased with the increase of the isoliquirigenin concentration (F=359.219 and 431.324， P < 0.05). Conclusion Isoliquiritigenin can obviously inhibit invasion ability of SGC7901 cells, which may be related to the down regulation of the signal transduction pathway protein PI3K/Akt and the down steam protein MMP9.

Key words: glycyrrhiza uralensis, stomach neoplasms, matrix metalloproteinase 9, isoliquiritigenin,  invasive ability, PI3K/Akt, Akt,  P-Akt