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OBJECTIVE：To study the effects of citrusinol on proliferation ，migration and the expression of skeleton-related proteins of human hepatocellular cells HepG 2，and to investigate its interaction mode with skeleton-related proteins. METHODS ： CCK-8 assay was used to detect the effects of different concentrations （12.5，25，50，100，200 μmol/L）of citrusinol on the proliferation of HepG 2 cells for 24 h. HepG 2 cells were divided into negative control group ，citrusinol low-concentration and high-concentration groups （50，100 μmol/L citrusinol）. After treated for 24 h，the migration of HepG 2 cells was detected by cell scratch test ；cell migration rate was calculated. mRNA and protein expression of F-actin ，β-tubulin and Ezrin in HepG 2 cells were determined by RT-PCR and Western blotting assay. Molecular docking software Schrodinger 2015 was used to analyze the interaction mode between citrusinol and above 3 kinds of proteins. RESULTS ：Citrusinol showed significant inhibition effect on the proliferation of HepG 2 cells （P＜0.05 or P＜0.01），in dose-dependent trend. Compared with negative control group ，cell migration， mRNA and protein expression levels of F-actin ， β-tubulin， Ezrin were decreased significantly in citrusinol low-concentration and high-concentration groups （P＜0.05 or P＜0.01）. Molecular docking results showed that the citrusinol could form hydrogen bond and hydrophobic bond with the above 3 skeleton-related proteins. CONCLUSIONS ：Citrusinol can inhibit the proliferation and migration of HepG 2 cells，the mechanism may be associated with the down-regulation of mRNA and protein expression of F-actin ，β-tubulin and Ezrin. The mode of its interaction with skeleton-related proteins may be the formation of hydrogen bond or hydrophobic bond.
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Objective The inclusion complex of vincamine (VIN) and hydroxypropyl-β-cyclodextrin (HP-β-CD) was prepared and characterized. Molecular simulation method was used to study the formation mechanism of inclusion complex. Methods The inclusion complex of VIN/HP-β-CD was prepared by saturated solution. The preparation technology of VIN/HP-β-CD inclusion complex was optimized by orthogonal design, and taking the drug-loading of the inclusion compound as the index. The stability constant of inclusion complex between VIN and HP-β-CD was studied by UV-Vis spectrometry titration, and the inclusion ratio was determined by Job plots method. The VIN/HP-β-CD inclusion complex was characterized by scanning electron microscope (SEM), X-ray powder diffractometry (XRD), infrared spectroscopy (IR), thermal analysis techniques (TG and DSC), and nuclear magnetic resonance (1H, 2D NMR). The water solubility of the VIN/HP-β-CD inclusion complex was measured and the stability test was conducted in the simulated human gastric juice and intestinal fluid environment. Molecular docking and molecular dynamics were used to study the forming mechanism of supramolecular system of VIN/HP-β-CD. Results Using saturated solution method, the optimum conditions of inclusion were: 1:1 for molar ratio of VIN and HP-β-CD, 40 ℃ for inclusion temperature, 7 h for inclusion time and volume ratio of methanol to water (1:6) as solvent; Job curve and UV-vis spectroscopy showed that inclusion ratio of host-guest inclusion complexes was 1:1; After VIN formed inclusion complexes with HP-β-CD, its solubility increased from 0.04 mg/mL to 16.5 mg/mL, and the thermal decomposition temperature of VIN increased from 240.5 ℃ to 306.1 ℃. 1H-NMR and NOESY spectra indicated that the inclusion complex was formed by the a-ring of VIN entering from the large end of HP-β-CD. Quantum chemical calculation and molecular docking indicated that the optimal inclusion mode was consistent with the results of NMR studies. Molecular dynamics studies showed that VIN can penetrate into the hydrophobic cavity of HP-β-CD in water environment, and the interaction between host and guest was strengthened. The space size of host-guest matched better. Conclusion The solubility and thermal stability were significantly improved after the formation of inclusion complex with VIN and HP-β-CD. Hydrophobicity, hydrogen bonding, and van der Waals forces were the main driving forces for inclusion complex formation.
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Objective: To prepare tetrahydropalmatine (THP) and β-cyclodextrin (β-CD) and its derivatives inclusion complexes (HP-β-CD, DM-β-CD, and TM-β-CD and explore their inclusion behavior and properties. Methods: The inclusion complexes of THP with β-CD, HP-β-CD, DM-β-CD, and TM-β-CD were prepared by saturated solution. The inclusion ratio and stability constant of inclusion complexes were determined with the Job plot and UV-vis spectroscopy. The THP/CDs complexes were characterized and determinated by means of XRD, TG, and SEM. The molecular simulation was processed to investigate the inclusion behavior of THP and different CDs. The water solubility of the inclusion complexes was measured and the stability test was conducted in the simulated human gastric juice and intestinal fluid environment. Results: Job plot and UV-vis spectroscopy showed that inclusion ratio of host-guest inclusion complexes was 1:1. Molecular docking showed that the entire THP entered the macrophage port and run through the cavities of β-CD and DM-β-CD, with the two aromatic rings located at the large and small mouth, respectively. For HP-β-CD and TM-β-CD, the two nitrogen heterocycle of THP were “V” shaped inlaid into the CD cavity, and both aromatic rings were located at the large end of the CDs. Conclusion: The solubility of tetrahydropalmatine was increased from 0.30 mg/mL to 1.60, 3.40, 9.13, and 4.02 mg/mL for β-CD, HP-β-CD, DM-β-CD, and TM-β-CD, respectively. The thermal stability and biological environment stability had been significantly improved.
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Objective To introduce the application of SwissDock in prediction of protein and small molecule docking , and provide reference for usage of SwissDock.Methods Chooseing baicalin (small molecule) and BMPRII (target protein) as study objects, operation processes of SwissDock system were described in detail and results were analyzed.Results The prediction result of SwissDock systew demonstrates that ASN338 is found as the binding site of docking, and the distance between ASN338 and baicalin is 3.5?and G=-13.17 kcal/mol.Conclusion SwissDock can help usersto submit dockings and retrieve predicted complexes.The system including simple operation interface and good human-computer interaction, it will be a powerful tool for researches of molecular recognition on the atomic scale .
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Objective To screen the non-nucleoside compounds against HIV-1 reverse transcriptase by molecular modeling and bioactivity assay. Methods Surflex-Dock module of Tripos SYBYL software was used to simulate the binding pattern of 22 000 compounds in SPECS database with the active pocket of HIV-1 reverse transcriptase. Based on the simulation results, the interaction mode between the above compounds and the crystal structure of HIV-1 reverse transcriptase was analyzed. The compounds with higher docking scores and better binding pattern were determined by anti-HIV-1 ac tivities test in vitro. Results The virtual screening results showed that the docking conformation of 1- (4-fluorophenyl) -3- [2- (1H-indol-3-yl) ethyl] thiourea was similar to the embedded ligand in Rilpivirine crystal structure. 1- ( 4-fluorophenyl) -3- [ 2- ( 1H-indol-3-yl) ethyl] thiourea was held together with the key residue Lys101 in docking pocket of HIV-1 reverse transcriptase by hydrogen bonds, and hadπ-πstacking action together with the conservative residue Trp229 and the aromatic residue Tyr181 respectively. The bioassay in vitro results showed that when the proliferation rate of C8166 lymphocyte syncytium infected by HIV-1ⅢB arrived 50% ( EC50) , the concentration of 1- ( 4-fluorophenyl) -3- [ 2- ( 1H-indol-3-yl) ethyl] thiourea was 5.45μg/mL. Conclusion Molecule docking technology is an effective approach to reducing the screening of candidate compounds with micromolecular activity, and can be used to predict the interaction mode between the compound and the target receptor. In the study, active compound 1- (4-fluorophenyl) -3- [2- (1H-indol-3-yl) ethyl] thiourea has been screened out by molecule docking technology.