Pharmacological mechanism analysis of oligopeptide from Pinctada fucata based on in silico proteolysis and protein interaction network / 中国中药杂志

Pinctada fucata oligopeptide is one of key pharmaceutical effective constituents of P. fucata. It is significant to analyze its pharmacological effect and mechanism. This study aims to discover the potential oligopeptides from P. fucata and analyze the mechanism of P. fucata oligopeptide based on in silico technologies and protein interaction network(PIN). First, main protein sequences of P. fucata were collected, and oligopeptides were obtained using in silico gastrointestinal tract proteolysis. Then, key potential targets of P. fucata oligopeptides were obtained through pharmacophore screening. The protein-protein interaction(PPI) of targets was achieved and implemented to construct PIN and analyze the mechanism of P. fucata oligopeptides. P. fucata oligopeptide database was constructed based on in silico technologies, including 458 oligopeptides. Twelve modules were identified from PIN by a graph theoretic clustering algorithm Molecular Complex Detection(MCODE) and analyzed by Gene ontology(GO) enrichment. The results indicated that P. fucata oligopeptides have an effect in treating neurological diseases, such as Alzheimer's disease. In silico proteolysis could be used to analyze the protein sequences of traditional Chinese medicine(TCM). According to the combination of in silico proteolysis and PIN, the biological activity of oligopeptides could be interpreted rapidly based on the known TCM protein sequence. The study provides the methodology basis for rapidly and efficiently implementing the mechanism analysis of TCM oligopeptides.

Prediction of ETA oligopeptides antagonists from Glycine max based on in silico proteolysis / 中国中药杂志

Oligopeptides are one of the the key pharmaceutical effective constituents of traditional Chinese medicine(TCM). Systematic study on composition and efficacy of TCM oligopeptides is essential for the analysis of material basis and mechanism of TCM. In this study, the potential anti-hypertensive oligopeptides from Glycine max and their endothelin receptor A (ETA) antagonistic activity were discovered and predicted based on in silico technologies.Main protein sequences of G. max were collected and oligopeptides were obtained using in silico gastrointestinal tract proteolysis. Then, the pharmacophore of ETA antagonistic peptides was constructed and included one hydrophobic feature, one ionizable negative feature, one ring aromatic feature and five excluded volumes. Meanwhile, three-dimensional structure of ETA was developed by homology modeling methods for further docking studies. According to docking analysis and consensus score, the key amino acid of GLN165 was identified for ETA antagonistic activity. And 27 oligopeptides from G. max were predicted as the potential ETA antagonists by pharmacophore and docking studies.In silico proteolysis could be used to analyze the protein sequences from TCM. According to combination of in silico proteolysis and molecular simulation, the biological activities of oligopeptides could be predicted rapidly based on the known TCM protein sequence. It might provide the methodology basis for rapidly and efficiently implementing the mechanism analysis of TCM oligopeptides.

Synergistic mechanism of traditional Chinese medicine based on target combination of PepT1 and PPARα / 中国中药杂志

Synergistic effect is main pharmacological mechanism of traditional Chinese medicine(TCM). The research method based on the key targets combination is an important method to explore the synergistic effect of TCM. Peptide transporter 1 (PepT1) is an essential target for drug uptake into the bloodstream, accounting for about 50% of the total transporter protein content from the small intestine. Peroxisome proliferator-activated receptor α(PPARα) is the lipid-lowering target of fibrates, which have a good hypolipidemic effect by activating PPARα. It has been reported that PPARα could activate the gene expression of PepT1s, and PPARα agonists can promote the uptake of PepT1 substrates, indicating their synergistic effect. In this paper, PepT1 substrates and PPARα agonists from TCM were discovered, and their synergistic mechanism was also been discussed based on the target combination of PepT1 and PPARα. The support vector machine(SVM) model of PepT1 substrates was first constructed and utilized to predict potential TCM components. Meanwhile, merged pharmacophore and docking model of PPARα agonists was used to screen the potential active ingredients from TCM. According to the analysis results of two groups, the TCM combination of Panax notoginseng and Ganoderma lucidum, as well as TCM combination of P. notoginseng and Salvia miltiorrhiza were identified to have the synergistic mechanism based on target combination of PepT1 and PPARα. In this study, synergistic mechanism of TCM was analyzed for absorption and hypolipidemic effect based on target combination, which provides a new way to explore the synergetic mechanism of TCM related to pharmacokinetics.

Discovery of potential LXRβ agonists from Chinese herbs using molecular simulation methods / 中国中药杂志

Liver X receptor β (LXRβ) has been a new target in the treatment of hyperlipemia, which was related to the cholesterol homeostasis. In this study, the quantitative pharmacophores were constructed by 3D-QSAR pharmacophore (Hypogen) method based on the LXRβ agonists. The optimal pharmacophore model containing one hydrogen bond acceptor, two hydrophobics and one ring aromatic was obtained based on five assessment indictors, including the correlation between predicted value and experimental value of the compounds in training set (correlation), Δcost of the models (Δcost), hit rate of active compounds (HRA), identification of effectiveness index (IEI) and comprehensive evaluation index (CAI). And the values of the five assessment indicators were 0.95, 128.65, 84.44%, 2.58 and 2.18 respectively. The best model as a query to screen the traditional Chinese medicine database (TCMD), a list of 309 compounds was obtained andwere then refined using Libdock program. Finally, based on the screening rules of the Libdock score of initial compound and the key interactions between initial compound and receptor, four compounds, demethoxycurcumin, isolicoflavonol, licochalcone E and silydianin, were selected as potential LXRβ agonists. The molecular simulation methods were high-efficiency and time-saving to obtainthe potential LXRβ agonists, which could provide assistance for further researchingnovel anti-hyperlipidemia drugs.

Virtual screening for natural CETP inhibitors by structure-based pharmacophore / 中国中药杂志

Cholesterol ester transfer protein (CETP) is a key regulator of high density lipoprotein (HDL). Owing to its important role in the reverse of cholesterol transport, CETP has become a hotspot target in modulating lipid drug design. In this paper, structure based pharmacophore (SBP) models for CETP inhibitors were built based on the protein structure 4F2A from Protein Database (PDB). The best pharmacophore contained six hydrophobic features, one hydrogen bond acceptor feature and nine excluded volume features, with the N and CAI value was 3.33 and 2.31 respectively. Then the model was used to search the traditional Chinese medicine database (TCMD) and 629 compounds originated from 315 TCM herbs were obtained. Molecular docking was also used to validate SBP by analyzing the critical amino acid residue and the interaction between potential active compounds and receptor. In this study, several TCM herbs, like Lycii Frutus and Schisandrae chinensis fructus, which contained more optimal SBP based screening results, have been reported hypolipidemic effect, and need to be studied deeply in a more focused research on herbal active constituents. Therefore, this study could provide reliable fundamental data for exploring the action mechanisms of TCM, and be applicable to identify lead candidates, which can be utilized as starting scaffolds for natural CETP inhibitors.

Application of CADD on multi-target drug R&D in natural products / 中国中药杂志

Multi-target drugs can simultaneously adjust multiple links of the disease network. Despite the higher efficacy and lower toxicity caused by single targets, multi-target drugs become ideal drugs for treating complicated diseases as well the main direction of drug R & D. By virtue of their structural diversity, higher multi-target activity and lower toxicity, natural products become an important source for developing multi-target drugs. Computer-aided drug design (CADD) is a commonly used multi-target drug R&D method, which mainly includes virtual screening and pharmacophore design. In this paper, the authors made a systematical analysis and discussed the prospects and advantages of various methods for multi-target drug R&D with natural products.

Study on structure-activity relationship of flavonoids' multidrug resistance-associated protein inhibitory activity / 中国中药杂志

To study the quantitative structure-activity relationship (QSAR) between the stuctures of 29 flavonoids and the inhibitory activity of their multidrug resistance-associated protein (MRP) 1 and 2 by using the comparative molecular similarity index analysis (CoMSIA). By studying the impact of the combination of different molecular force fields, researchers obtained the molecular force fields that played an important role in inhibiting the activity of MRP1 and MRP2, built the optimized QSAR model, and discussed the structural modification method for flavonoids' multidrug resistance-associated protein inhibitor. The results of the study could not only provide the guidance for new drug R&D, but also help partially discuss the synergy mechanism between MRP1 and MRP2 receptors and traditional Chinese medicines containing flavonoids.

Study on lipid-lowering traditional Chinese medicines based on pharmacophore technology and patent retrieval / 中国中药杂志

The combined application of statins that inhibit HMG-CoA reductase and fibrates that activate PPAR-α can produce a better lipid-lowering effect than the simple application, but with stronger adverse reactions at the same time. In the treatment of hyperlipidemia, the combined administration of TCMs and HMG-CoA reductase inhibitor in treating hyperlipidemia shows stable efficacy and less adverse reactions, and provides a new option for the combined application of drugs. In this article, the pharmacophore technology was used to search chemical components of TCMs, trace their source herbs, and determine the potential common TCMs that could activate PPAR-α. Because there is no hyperlipidemia-related medication reference in modern TCM classics, to ensure the high safety and efficacy of all selected TCMs, we selected TCMs that are proved to be combined with statins in the World Traditional/Natural Medicine Patent Database, analyzed corresponding drugs in pharmacophore results based on that, and finally obtained common TCMs that can be applied in PPAR-α and combined with statins. Specifically, the pharmacophore model was based on eight receptor-ligand complexes of PPAR-α. The Receptor-Ligand Pharmacophore Generation module in the DS program was used to build the model, optimize with the Screen Library module, and get the best sub-pharmacophore, which consisted of two hydrogen bond acceptor, three hydrophobic groups and 19 excluded volumes, with the identification effectiveness index value N of 2. 82 and the comprehensive evaluation index CAI value of 1. 84. The model was used to screen the TCMD database, hit 5,235 kinds of chemical components and 1 193 natural animals and plants, and finally determine 62 TCMs. Through patent retrieval, we found 38 TCMs; After comparing with the virtual screening results, we finally got seven TCMs.