Puerarin inhibits growth and induces apoptosis in SMMC-7721 hepatocellular carcinoma cells

Puerarin, a predominant isoflavonoid compound extracted from the Chinese medicinal herb Radix Puerariae, is considered to exhibit an antitumor effect. In the present study, the effects of puerarin on SMMC-7721 human hepatocellular carcinoma cells were investigated. Cell viability was assessed by MTT assay. Apoptosis was detected by flow cytometry with Annexin V-fluorescein isothiocyante staining and morphological observation of nuclear changes by Hoechst staining. The mitochondrial membrane potential (MMP) was monitored using rhodamine 123. The generation of reactive oxygen species (ROS) was quantified using dichloro-dihydro-fluo-. rescein diacetate. Polymerase chain reaction and western blot analysis were used to detect the expression levels of apoptosis-associated genes. The results revealed that high concentrations of puerarin (500, 1,000 and 1,500 mu g/ml) significantly inhibited the proliferation of SMMC-7721 cells in a time- and dose-dependent manner. Simultaneously, apoptotic rates were increased and cell morphology was changed following puerarin treatment. Furthermore, puerarin-induced apoptosis of SMMC-7721 cells was associated with loss of MMP and generation of ROS. Puerarin treatment increased caspase-3,8,9 and apoptosis-inducing factor (AIF) mRNA expression levels in SMMC-7721 cells, while the phosphorylation levels of P38, extracellular signal-regulated kinase (ERK1) and c-Jun N-terminal kinase were also increased. Furthermore, caspase-9 and AIF protein expression was upregulated. In conclusion, puerarin inhibited proliferation and induced apoptosis in SMMC-7721 cells via the mitochondria-dependent pathway; however, the specific mechanisms require further investigation.