Virtual Screening And Interaction Mechanism Of Novel Thrombin Inhibitors And Functional Food Components

Cardiovascular diseases pose a serious problem for human health.Although the blood coagulation pathways are very complicated,the central role of thrombin in the entire coagulation cascade mechanism is still quite prominent.Therefore,this extremely critical coagulation factor become an important target for thrombosis prevention and treatment.The emergence of novel medicines and functional foods with low-toxicity and high-efficiency always has been expected.Natural products of medicine and food homologous are favored in the development of new medicines and functional foods by their unique properties.However,the increase of investment in the marketing of new medicines and the success rate are not proportional in reality.Faced with this situation,we will continue to maintain the exclusive characteristics of drugs for treating diseases.The idea of drug relocation can alleviate the dilemma of new medicine by the heterogeneity of drugs,which explores its new effects from drugs with multiple pharmacology.On the other hand,weakening the therapeutic effect of drugs and integrating the effective ingredients into the daily diet are also a trend.It develops effective natural products into functional foods to achieve the purpose of preventing and curing diseases in our daily life.Therefore,the study is mainly to screen the FDAapproved drug database and natural product database.Analyzing the micro-interaction between the compound and thrombin by molecular simulation.Finally,we verify the screened compounds by experiments.The main research contents and results of this article are as follows:Ⅰ:The 2682 FDA-approved drugs were cross-screened by the two docking methods and six small molecules with anticoagulant effects were obtained.From the interaction analysis of molecular docking,it could be seen that the hydrogen bond interaction was the core.Many van der Waals forces were widely distributed.We inferred that the six regions(His57-Lys60 F,Trp96-Asp102,Asn143-Gln151,Glu164-Asp178,Asp189-Ser195,and Ser214-Phe227)were the key sites related to the stability of the complex by decomposing the binding free energy.In addition,we also found that van der Waals Force was the main driving force for binding,which was consistent with the result of molecular docking.Comparing six kinds of drugs,the changes in the secondary structure of Valganciclovir were the same as the Atragaban(direct thrombin inhibitor).In addition,the binding free energy of Valganciclovir was also the smallest.Ⅱ:Through the cross-analysis of semi-flexible docking,six functional components(phenylethanol glycosides)were screened from 2054 natural products.The docking results revealed that hydrogen bonding,hydrophobic interaction and van der Waals interaction were beneficial to the stability of the complex.Enzyme inhibition experiments verified that four natural compounds(Plantamajoside,Verbascoside,Forsythoside A and Calceolarioside B)could effectively inhibit the activity of thrombin.Fluorescence spectroscopy showed that Calceolarioside B was a better functional food component.Molecular dynamics simulations and MM-PBSA calculations explained that the binding free energy of the complex was consistent with the results of enzyme inhibition.In addition,the free energy of decomposition further illustrated that the van der Waals force mainly derived the combination of the complexes.The fluorescence spectrum also reflected this conclusion.Based on the combination of theoretical calculations and verification evidence,we speculated that phenylethanol glycoside was a kind of natural compounds with great anticoagulant potential.The above results indicated that the six-screened drugs have great potential to develop into thrombin inhibitors.The analysis of the theoretical mechanism may also provide new ideas for modifying the structure.In addition,it also explained that the Phenyl Ethanol Glucoside B was possibly developed into a new type of anti-thrombotic functional food,which was selected from the natural products of the food and medicine homology.Moreover,we speculated that Phenyl Ethanol Glucoside compound was extremely related to anticoagulation.This study will help to provide a certain reference for the designing of new thrombin inhibitors and the development of new functional foods.