An ordered mesoporous silica ( OMS ) was synthesized through hydrothermal process. The synthesized material was characterized by different techniques such as X-ray diffraction, nitrogen adsorption-desorption and transmission electron microscope. The electrochemical characteristics of the OMS modified carbon paste electrode ( OMS/CPE ) were investigated by using cyclic voltammetry and electrochemical impedance spectroscopy. Compared with bare carbon paste electrode ( CPE ) , the OMS/CPE exhibited a larger electrode surface and a faster electron-transfer rate. Electrochemical behaviors and kinetic properties of L-tryptophan ( L-Trp) at the OMS/CPE in the presence of sodium dodecylsulphate ( SDS) were studied. The results showed that the voltammetric response of L-Trp at OMS/CPE was improved due to the synergistic effect of OMS and SDS. The electrochemical oxidation of L-Trp at OMS/CPE in the presence of SDS was an irreversible process involved two electrons and two protons, and the electrode process was controlled by the adsorption step. Some parameters such as SDS concentration, accumulation time, accumulation potential and pH were optimized. Under optimal conditions, the oxidation peak current was linearly proportional to L-Trp concentration in the range of 8. 0×10-8 to 4. 0×10-6 mol/L, with a detection limit of 7. 0×10-8 mol/L (S/N=3 ) . The proposed method was applied for the determination of L-Trp in oral liquid with the recoveries of 99 . 6%-102 . 6%.

Aim To study the apoptotic inducing effects of deguelin on SH-SY5Y cells.Methods SH-SY5Y cells were treated with 0,0.625,1.25,2.5,5,10 and 20 μmol·L-1 deguelin for different time(24,48,72 h);cell viability was detected by CCK-8 assay.SH-SY5Y cells were treated with 0,8,20,50 μmol·L-1 deguelin for 24 h;light microscope and AO/EB double stained method were employed for observing the morphology and apoptotic morphology of treated cells.Apoptotic rate of treated cells was determined by flow cytometry.Cells were stained by DCFH-DA,and the whole reactive oxygen species(ROS)was determined by flow cytometry.Spectrophotometry was employed to determine the activation degree of caspase-3.Results Deguelin inhibited cell growth in a time-and dose-dependent manner,and the IC50 value of deguelin was(26.07±2.18),(18.33±0.94),(12.5±1.49)μmol·L-1 when treated with 24,48,72 h respectively.After treated with 8,20,50 μmol·L-1 deguelin for 24 h,cell apoptotic rate,ROS and activation rate of caspase-3 increased markedly(P<0.05),all of which performed a dose related effect.Conclusion Deguelin can inhibit SH-SY5Y cell proliferation and induce cell apoptosis,and the mechanism may be concerned with the elevated ROS and activated caspase-3.