Research On Computer-Aided Drug Design, Synthesis And Initial Activity Evaluation Of γ-Secretase Inhibitors With Neuroprotective Effect

Alzheimer's disease (AD), which is also called senile dementia, is a progressive neurodegenerative disorder in the elderly in central nervous system. So the pathogenesy of Alzeheimer's disease have not yet been fully elucidated. Generally it was related with protein Tau modification, neurotoxicity of Aβand nerve cell apoptosis. The current hypothesis causing AD is aberrant production ofβ-amyloid (Aβ) and plaque deposition in the brain.γ-secretase, a key enzyme in the production of Aβ, is potential target for the treatment of AD. And then Aβhas neurotoxicity, so newγ-secretase inhibitors with neuroprotective effect has favorable perspective.But because the structure ofγ-secretase was not ascertained, the structure of the binding-site and mechanism of the drug were not distinct. So study on structure-activity relationship of a series of active compounds, then associating with conformational analysis, summarize the pharmacophore model including the atom group and the spatial relationship, which is important to the activity. This method could be used to instruct the design of newγ-secretase inhibitors.The research object matter in this paper included as follows:1. Building the pharmacophore model and designing the target compounds.The pharmacophore model ofγ-secretase inhibitors was established by the computer-aided drug design software, catalyst, with the training set of benzodiazepine-basedγ-secretase inhibitors. As PARP inhibitors have event neuroprotective effect, so the pharmacophore model of PARP inhibitors was built through known PARP inhibitors. Then search new structure compounds in MDL database by the pharmacophore model ofγ-secretase inhibitors to definite the leading compounds. Then select the better matching compounds through putting leading compound into the pharmacophore model of PARP inhibitors. So target compounds were obtained, which have good estimate activity to inhibit theγ-secretase and PARP.2. Synthesizing and identifying the target compounds.The intermediate-product N-phenylglycine ethyl ester derivative was synthesized from aniline derivatives by the substitution reaction. It was also synthesized by microwave irradiation technology, which shortened reaction time. Then five compounds with new structure by acylation reaction were synthesized. All compounds were identified by HPLC, UV, IR, 1H-NMR or 13C-NMR.3. Pharmacological activity test in vitroAll target compounds and PFT-αwere assessed for their ability in vitro to protect PC12 cells against H2O2 induced apoptosis through MTT methods. The results suggested that compound 3a, 3b and 3c have dual activity of neurotrophy and apoptosis inhibiting activity on oxidation stress damaged PC12 cell. Though compound 3d and 3e have not distinct effect on inhibiting the activity on oxidation stress damaged PC12 cell apoptosis, they have the neurotrophic effect on PC12 cell.The characters and innovation points1. Good pharmacophore models ofγ-secretase inhibitors and PARP inhibitors were built respectively by using the computer-aided drug design software—Catalyst. On the basis of above, five new-structure compounds were designed and synthesized, which areγ-secretase inhibitors with neuroprotective effect. Research results about anti- apoptosis of neurocyte in vitro indicated that all the compounds have the neuroprotective effect. Finally the validity of the pharmacophore model was verified.2. The microwave irradiation technology was used in the intermediate-products synthesis, and the reaction time was shortened far and away.3. The neurotrophic activity and apoptosis inhibition activity of ethyl N-phenyl-N-[(ethoxycarbonyl)methyl]succinamate derivatives was discovered.