In silico Study of Acetylcholinesterase and Beta-secretase Inhibitors: Potential Multitarget Anti-Alzheimer's Agents.

BACKGROUND: Alzheimer's disease is a progressive neurodegenerative process with multifactorial characteristics. This disease follows the natural aging process, affecting mainly people over 65 years. Pharmacotherapeutic treatment currently combats symptoms related to cognitive function. Several targets have begun to attract the interest of the scientific community to develop new drug candidates which have better pharmacokinetic and lower toxicity parameters. OBJECTIVE: The present study aims to design new candidates for acetylcholinesterase/ß-secretase (AChE/BACE1) multitarget inhibitor drugs. METHODS: 17 natural products were selected from the literature with anticholinesterase activity and 1 synthetic molecule with inhibitory activity for BACE1. Subsequently, the molecular docking study was performed, followed by the derivation of the pharmacophoric pattern and prediction of pharmacokinetic and toxicological properties. Finally, the hybrid prototype was designed. RESULTS: All selected molecules showed interactions with their respective target enzymes. Derivation of the pharmacophoric pattern from molecules that interacted with the AChE enzyme resulted in 3 pharmacophoric regions: an aromatic ring, an electron-acceptor region and a hydrophobic region. The molecules showed good pharmacokinetic and toxicological results, showing no warnings of mutagenicity and/or carcinogenicity. After the hybridization process, three hybrid molecules were obtained, which showed inhibitory activity for both targets. CONCLUSION: It is concluded that research in the field of medicinal chemistry is advancing towards the discovery of new drug candidates that bring a better quality of life to patients with AD.

Potential colchicine binding site inhibitors unraveled by virtual screening, molecular dynamics and MM/PBSA.

Microtubules have been widely studied in recent decades as an important pharmacological target for the treatment of cancer especially due to its key role in the mitosis process. Among the constituents of the microtubules, αß-tubulin dimers stand out in view of their four distinct interaction sites, including the so-called colchicine binding site (CBS) - a promising target for the development of new tubulin modulators. When compared to other tubulin sites, targeting the CBS is advantageous because this site is able to host ligands with lower molecular volume and lipophilicity, thus reducing the chances of entailing the phenomenon of multiple drug resistance (MDR) - one of the main reasons of failure in chemotherapy. However, colchicine, the first ligand ever discovered with affinity towards the CBS, despite modulating the action of microtubules, has shown toxicity in clinical studies. Therefore, in order to expand the known chemical space of scaffolds capable of interacting with CBS and to design non-toxic colchicine binding site inhibitors, we conducted a robust virtual screening pipeline. This has been rigorously validated and consisted of ligand- and structure-based methodologies, which allowed us to select four promising CBS inhibitors called tubLCQF1-4. These four compounds were also evaluated with long trajectories molecular dynamics simulations and respective results were used for the theoretical determination of the free energy released in the formation of the complexes, using the Molecular Mechanics Poisson-Boltzmann Surface Area (MM/PBSA) methodology.

Molecular Docking, Physicochemical Properties, Pharmacokinetics and Toxicity of Flavonoids Present in Euterpe oleracea Martius.

BACKGROUND: Euterpe oleracea Martius, popularly known as açaí, is a fruit rich in α- tocopherols, fibers, lipids, mineral ions, and polyphenols. It is believed that the high content of polyphenols, especially flavonoids, provides several health-promoting effects to the açaí fruit, including anti-inflammatory, immunomodulatory, antinociceptive and antioxidant properties. Most of the flavonoids are antioxidant molecules of plant origin that act as a trap for free radicals, reacting and neutralizing them, thus offering perspectives in preventing oxidative damage. OBJECTIVE: In this study, we aim to perform an in silico evaluation of flavonoids present in the pulp and the oil of Euterpe oleracea Martius, evaluating their potential to serve as antioxidant agents. METHODS: Firstly, we selected 16 flavonoids present in Euterpe oleracea Martius pulp and oil, and then their physicochemical properties were analyzed concerning the Lipinski's Rule of Five. Moreover, we evaluated their pharmacokinetic properties using the QikProp module of the Schrödinger software as well as their toxicity profile, using the DEREK software. Docking simulations, using the GOLD 4.1 software, as well as pharmacophoric hypotheses calculation of molecules were also performed. RESULTS: Flavonoids present in the açaí pulp including catechin, epicatechin, luteolin, chrisoeriol, taxifolin, apigenin, dihydrokaempferol, isovitexin, and vitexin presented good oral bioavailability. Regarding the pharmacokinetic properties, the compounds catechin, epicatechin, isovitexin, luteolin, chrisoeriol, taxifolin, and isorhamnetin rutinoside presented the best results, besides high human oral absorption. Regarding the prediction of toxicological properties, compounds isorhamnetin rutinoside and rutin presented mutagenicity for hydroxynaphthalene or derivate, and regarding the docking simulations, all the compounds investigated in this study presented key interactions with the corresponding targets. CONCLUSION: The flavonoids catechin, chrysoeriol, and taxifolin presented the best results according to the evaluation conducted in this study. These computational results can be used as a theoretical basis for future studies concerning the development of drug candidates, as well as to enlighten biological tests in vitro and in vivo, which can contribute to the treatment of neurodegenerative diseases, such as Alzheimer's disease, Parkinson's disease, and Huntington's disease.

Identification of novel αß-tubulin modulators with antiproliferative activity directed to cancer therapy using ligand and structure-based virtual screening.

Among several strategies related to cancer therapy targeting the modulation of αß-tubulin has shown encouraging findings, more specifically when this is achieved by inhibitors located at the colchicine binding site. In this work, we aim to fish new αß-tubulin modulators through a diverse and rational VS study, and thus, exhibiting the development of two VS pipelines. This allowed us to identify two compounds 5 and 9 that showed IC50 values of 19.69 and 21.97 µM, respectively, towards possible modulation of αß-tubulin, such as assessed by in vitro assays in C6 glioma and HEPG2 cell lines. We also evaluated possible mechanisms of action of obtained hits towards the colchicine binding site of αß-tubulin by using docking approaches. In addition, assessment of the stability of the active (5 and 9) and inactive compounds (3 and 13) within the colchicine binding site was carried out by molecular dynamics (MD) simulations, highlighting the solvent effect and revealing the compound 5 as the most stable in the complex. At last, deep analysis of these results provided some valuable insights on the importance of using mixed ligand- and structure-based strategies in VS campaigns, in order to achieve higher chemical diversity and biological effect as well.

Antioxidant Effect of Flavonoids Present in Euterpe oleracea Martius and Neurodegenerative Diseases: A Literature Review.

INTRODUCTION: Neurodegenerative diseases (NDDs) are progressive, directly affecting the central nervous system (CNS), the most common and recurrent are Alzheimer's disease (AD) and Parkinson's disease (PD). One factor frequently mentioned in the etiology of NDDs is the generation of free radicals and oxidative stress, producing cellular damages. Studies have shown that the consumption of foods rich in polyphenols, especially those of the flavonoid class, has been related to the low risk in the development of several diseases. Due to the antioxidant properties present in the food, a fruit that has been gaining prominence among these foods is the Euterpe oleracea Mart. (açaí), because it presents in its composition significant amounts of a subclass of the flavonoids, the anthocyanins. METHODS: In the case review, the authors receive a basic background on the most common NDDs, oxidative stress and antioxidants. In addition, revisiting the various studies related to NDDs, including flavonoids and consumption of açaí. RESULTS: Detailed analysis of the recently reported case studies reveal that dietary consumption of flavonoid-rich foods, such as açaí fruits, suggests the efficacy to attenuate neurodegeneration and prevent or reverse the age-dependent deterioration of cognitive function. CONCLUSION: This systematic review points out that flavonoids presenting in açaí have the potential for the treatment of diseases such as PD and AD and are candidates for drugs in future clinical research. However, there is a need for in vitro and in vivo studies with polyphenol that prove and ratify the therapeutic potential of this fruit for several NDDs.

Virtual Screening and Statistical Analysis in the Design of New Caffeine Analogues Molecules with Potential Epithelial Anticancer Activity.

About 132 thousand cases of melanoma (more severe type of skin cancer) were registered in 2014 according to the World Health Organization. This type of cancer significantly affects the quality of life of individuals. Caffeine has shown potential inhibitory effect against epithelial cancer. In this study, it was proposed to obtain new caffeine-based molecules with potential epithelial anticancer activity. For this, a training set of 21 molecules was used for pharmacophore perception procedures. Multiple linear regression analyses were used to propose mono-, bi-, tri-, and tetra-parametric models applied in the prediction of the activity. The generated pharmacophore was used to select 350 molecules available at the ZINCpharmer server, followed by reduction to 24 molecules, after selection using the Tanimoto index, yielding 10 molecules after final selection by predicted activity values > 1.5229. These ten molecules had better pharmacokinetic properties than the other ones used as reference and within the clinically significant limits. Only two molecules show minor hits of toxicity and were submitted to molecular docking procedures, showing BFE (binding free energy) values lower than the reference values. Statistical analyses indicated strong negative correlations between BFE and pharmacophoric properties (high influence on BFE lowering) and practically null correlation between BFE and BBB. The two most promising molecules can be indicated as candidates for further in vitro and in vivo analyzes.

Structure- and ligand-based drug design of novel p38-alpha MAPK inhibitors in the fight against the Alzheimer's disease.

Alzheimer's disease (AD) is characterized microscopically by the presence of amyloid plaques, which are accumulations of beta-amyloid protein inter-neurons, and neurofibrillary tangles formed predominantly by highly phosphorylated forms of the microtubule-associated protein, tau, which form tangled masses that consume neuronal cell body, possibly leading to neuronal dysfunction and ultimately death. p38α mitogen-activated protein kinase (MAPK) has been implicated in both events associated with AD, tau phosphorylation and inflammation. p38α MAPK pathway is activated by a dual phosphorylation at Thr180 and Tyr182 residues. Drug design of p38α MAPK inhibitors is mainly focused on small molecules that compete for Adenosine triphosphate in the catalytic site. Here, we used different approaches of structure- and ligand-based drug design and medicinal chemistry strategies based on a selected p38α MAPK structure deposited in the Protein Data Bank in complex with inhibitor, as well as others reported in literature. As a result of the virtual screening experiments performed here, as well as molecular dynamics, molecular interaction fields studies, shape and electrostatic similarities, activity and toxicity predictions, and pharmacokinetic and physicochemical properties, we have selected 13 compounds that meet the criteria of low or no toxicity potential, good pharmacotherapeutic profile, predicted activities, and calculated values ​​comparable with those obtained for the reference compounds, while maintaining the main interactions observed for the most potent inhibitors.