Insight into the binding mode and the structural features of the pyrimidine derivatives as human A2A adenosine receptor antagonists

Exploration of chalcones and related heterocycle compounds as ligands of adenosine receptors: therapeutics development

Adenosine receptors (ARs) are ubiquitously distributed throughout the mammalian body where they are involved in an extensive list of physiological and pathological processes that scientists have only begun to decipher. Resultantly, AR agonists and antagonists have been the focus of multiple drug design and development programmes within the past few decades. Considered to be a privileged scaffold in medicinal chemistry, the chalcone framework has attracted a substantial amount of interest in this regard. Due to the potential liabilities associated with its structure, however, it has become necessary to explore other potentially promising compounds, such as heterocycles, which have successfully been obtained from chalcone precursors in the past. This review aims to summarise the emerging therapeutic importance of adenosine receptors and their ligands, especially in the central nervous system (CNS), while highlighting chalcone and heterocyclic derivatives as promising AR ligand lead compounds.

Computer-aided Drug Design Applied to Parkinson Targets

Background

Parkinson’s disease (PD) is a progressive neurodegenerative disorder characterized by debilitating motor deficits, as well as autonomic problems, cognitive declines, changes in affect and sleep disturbances. Although the scientific community has performed great efforts in the study of PD, and from the most diverse points of view, the disease remains incurable. The exact mechanism underlying its progression is unclear, but oxidative stress, mitochondrial dysfunction and inflammation are thought to play major roles in the etiology.

Objective

Current pharmacological therapies for the treatment of Parkinson’s disease are mostly inadequate, and new therapeutic agents are much needed.

Methods

In this review, recent advances in computer-aided drug design for the rational design of new compounds against Parkinson disease; using methods such as Quantitative Structure-Activity Relationships (QSAR), molecular docking, molecular dynamics and pharmacophore modeling are discussed.

Results

In this review, four targets were selected: the enzyme monoamine oxidase, dopamine agonists, acetylcholine receptors, and adenosine receptors.

Conclusion

Computer aided-drug design enables the creation of theoretical models that can be used in a large database to virtually screen for and identify novel candidate molecules.

Recent Developments and Applications of the MMPBSA Method

The Molecular Mechanics Poisson-Boltzmann Surface Area (MMPBSA) approach has been widely applied as an efficient and reliable free energy simulation method to model molecular recognition, such as for protein-ligand binding interactions. In this review, we focus on recent developments and applications of the MMPBSA method. The methodology review covers solvation terms, the entropy term, extensions to membrane proteins and high-speed screening, and new automation toolkits. Recent applications in various important biomedical and chemical fields are also reviewed. We conclude with a few future directions aimed at making MMPBSA a more robust and efficient method.

Carbamate substituted 2-amino-4,6-diphenylpyrimidines as adenosine receptor antagonists

A novel series of carbamate substituted 2-amino-4,6-diphenylpyrimidines was evaluated as potential dual adenosine A1 and A2A receptor antagonists. The majority of the synthesised compounds exhibited promising dual affinities, with A1Ki values ranging from 0.175 to 10.7 nM and A2AKi values ranging from 1.58 to 451 nM. The in vivo activity illustrated for 3-(2-amino-6-phenylpyrimidin-4-yl)phenyl morpholine-4-carboxylate (4c) is indicative of the potential of these compounds as therapeutic agents in the treatment of Parkinson's disease, although physicochemical properties may require optimisation.

Interaction mechanism exploration of HEA derivatives as BACE1 inhibitors by in silico analysis

The β-site amyloid precursor protein cleaving enzyme 1 (BACE1) initiates the generation of β-amyloid (Aβ) peptides which play a critical early role in the pathogenesis of Alzheimer's disease (AD), and thus it is a prime target for lowering the Aβ levels to treat AD.

2-Aminopyrimidines as dual adenosine A1/A2A antagonists

In this study thirteen 2-aminopyrimidine derivatives were synthesised and screened as potential antagonists of adenosine A1 and A2A receptors in order to further investigate the structure activity relationships of this class of compounds. 4-(5-Methylfuran-2-yl)-6-[3-(piperidine-1-carbonyl)phenyl]pyrimidin-2-amine (8m) was identified as a compound with high affinities for both receptors, with an A2AKi value of 6.34 nM and an A1Ki value of 9.54 nM. The effect of selected compounds on the viability of cultured cells was assessed and preliminary results indicate low cytotoxicity. In vivo efficacy at A2A receptors was illustrated for compounds 8k and 8m since these compounds attenuated haloperidol-induced catalepsy in rats. A molecular docking study revealed that the interactions between the synthesised compounds and the adenosine A2A binding site most likely involve Phe168 and Asn253, interactions which are similar for structurally related adenosine A2A receptor antagonists.

Anti-inflammatory, antioxidant, and antiparkinsonian effects of adenosine A2A receptor antagonists

The purpose of the study was to examine derivatives of annelated xanthines (imidazo-, pyrimido-, and diazepino-purinediones) for potential anti-inflammatory effects in carrageenan-induced paw edema in mice. Additionally, their antioxidant activity using the FRAP (ferric-reducing ability of plasma) assay and lipid peroxidation in rat brain homogenate were analyzed. All the studied derivatives showed affinity for adenosine A_2A receptor. The preliminary assays found that five (KD-114, KD-57, KD-129, KD-50, and KD-358) pyrimidopurinedione derivatives, administered intraperitoneally (i.p.) at a dose of 100mg/kg, had stronger anti-inflammatory effects. At a concentration of 10^-5M, three of the derivatives KD-57, KD-114, and KD-129 most influenced the total antioxidant ability. The most efficient anti-inflammatory compound, KD-114, also showed the strongest binding to A_2A receptors and when administered at a dose of 5mg/kg (i.p.), effectively reversed haloperidol-induced catalepsy and significantly increased the striatal extracellular dopamine level in the rat striatum. This effect was weaker than the one produced by CSC (1mg/kg i.p.), and only slightly weaker than that produced by ZM 241385 (3mg/kg i.p.) used as reference drugs. From the results of the present studies, it may be concluded that anti-inflammatory and antiparkinsonian effects of the examined compounds correlate with their influence on adenosine A_2A receptors, the most probable antagonism to these subtype receptors.

TCMSP: a database of systems pharmacology for drug discovery from herbal medicines

Background

Modern medicine often clashes with traditional medicine such as Chinese herbal medicine because of the little understanding of the underlying mechanisms of action of the herbs. In an effort to promote integration of both sides and to accelerate the drug discovery from herbal medicines, an efficient systems pharmacology platform that represents ideal information convergence of pharmacochemistry, ADME properties, drug-likeness, drug targets, associated diseases and interaction networks, are urgently needed.

Description

The traditional Chinese medicine systems pharmacology database and analysis platform (TCMSP) was built based on the framework of systems pharmacology for herbal medicines. It consists of all the 499 Chinese herbs registered in the Chinese pharmacopoeia with 29,384 ingredients, 3,311 targets and 837 associated diseases. Twelve important ADME-related properties like human oral bioavailability, half-life, drug-likeness, Caco-2 permeability, blood-brain barrier and Lipinski’s rule of five are provided for drug screening and evaluation. TCMSP also provides drug targets and diseases of each active compound, which can automatically establish the compound-target and target-disease networks that let users view and analyze the drug action mechanisms. It is designed to fuel the development of herbal medicines and to promote integration of modern medicine and traditional medicine for drug discovery and development.

Conclusions

The particular strengths of TCMSP are the composition of the large number of herbal entries, and the ability to identify drug-target networks and drug-disease networks, which will help revealing the mechanisms of action of Chinese herbs, uncovering the nature of TCM theory and developing new herb-oriented drugs. TCMSP is freely available at http://sm.nwsuaf.edu.cn/lsp/tcmsp.php.