RESUMEN
OBJECTIVE To investigate the effects of polyphyllin Ⅵ（PPⅥ） on the proliferation and apoptosis of glioma cells and potential mechanism. METHODS Using human glioma LN229 cells as objects， MTT assay was used to detect the survival rate after treated with different concentrations of PPⅥ [0 （control group）， 1， 2， 4， 8， 16， 32， 64 μmol/L] for different time （24， 48， 72 h）. The clone formation experiments were adopted to detect the number of cell clones and clone formation rate after being treated with different concentrations of PPⅥ [0 （control group）， 2， 4， 8 μmol/L] for 14 days. The flow cytometry and Western blot assay were used to detect the apoptotic rate of cells， the expressions of apoptosis-related protein [B cell lymphoma-2 （Bcl-2）， Bcl-2 associated X protein （Bax）， cleaved caspase-3]， and the expressions of related proteins of Fas/Fas ligand （FasL） death receptor pathway and protein kinase B （Akt）/glycogen synthesis kinase-3β （GSK-3β） pathway after being treated with different concentrations of PPⅥ [0（control group）， 4， 8 μmol/L] for 24 h. RESULTS Compared with the control group， the survival rate of cells， the number of clones and clone formation rate， the protein expression of Bcl-2， and the phosphorylation levels of Akt and GSK-3β protein were decreased significantly in different concentration groups of PPⅥ （P＜0.05 or P＜0.01）. The apoptotic rate， the protein expressions of Bax， cleaved caspase-3， Fas， FasL and cleaved caspase-8 were increased significantly （P＜0.05 or P＜ 0.01）. CONCLUSIONS PPⅥ can inhibit the proliferation and induce the apoptosis of human glioma LN229 cells， which may be related to the activation of the Fas/FasL death receptor pathway and the inhibition of the Akt/GSK-3β pathway.
RESUMEN
Five new saponins, including three steroid saponins, paristenoids A-C (1-3), and two triterpenoid saponins, paristenoids D-E (4-5), along with four known ones (6-9) were isolated from the rhizomes of Paris polyphylla var. stenophylla. The structures of the isolated compounds were identified mainly by detailed spectroscopic analysis, including extensive 1D and 2D NMR, MS, as well as chemical methods. Compound 3 is a new cyclocholestanol-type steroidal saponin with a rare 6/6/6/5/5 fused-rings cholestanol skeleton, and this skeleton has been first found from the genus Paris. The cytotoxicities of the isolated compounds against three human three glioma cell lines (U87MG, U251MG and SHG44) were evaluated, and compound 7 displayed certain inhibitory effect with IC50 values of 15.22 ± 1.73, 18.87 ± 1.81 and 17.64 ± 1.69 μmol·L-1, respectively.