Novel inhibitors of acetyl- and butyrylcholinesterase derived from the alkaloids dehydroevodiamine and rutaecarpine

Polyphosphoric Acid Esters Promoted Synthesis of Quinazolin-4(3H)-imines from 2-Aminobenzonitrile

A novel method for the synthesis of quinazolin-4(3H)-imines (QIs) by trimethylsilyl polyphosphate (PPSE) promoted reaction of 2-aminobenzonitrile with secondary amides is reported. The reaction is general and allows for the synthesis of N3-aryl and N3-alkyl QIs with variable 2-substituents affording high yields. The procedure was extended to derivatives bearing additional functional groups. The method is operationally simple, involves easily available starting materials and a mild dehydrating agent, with wide functional group tolerance. The reaction procedure proved to be suitable for scaling-up. A possible reaction path via an intermediate nitrilium ion is proposed on the basis of literature data and experimental observations.

Promising derivatives of rutaecarpine with diverse pharmacological activities

Rutaecarpine (RUT) is a natural pentacyclic indolopyridoquinazolinone alkaloid first isolated from one of the most famous traditional Chinese herbs, Evodia rutaecarpa, which is used for treating a variety of ailments, including headaches, gastrointestinal disorders, postpartum hemorrhage, amenorrhea, difficult menstruation, and other diseases. Accumulating pharmacological studies showed that RUT possesses a wide range of pharmacological effects through different mechanisms. However, its poor physicochemical properties and moderate biological activities have hampered its clinical application. In this regard, the modification of RUT aimed at seeking its derivatives with better physicochemical properties and more potency has been extensively studied. These derivatives exhibit diverse pharmacological activities, including anti-inflammatory, anti-atherogenic, anti-Alzheimer's disease, antitumor, and antifungal activities via a variety of mechanisms, such as inhibiting cyclooxygenase-2 (COX-2), acetylcholine (AChE), phosphodiesterase 4B (PDE4B), phosphodiesterase 5 (PDE5), or topoisomerases (Topos). From this perspective, this paper provides a comprehensive description of RUT derivatives by focusing on their diverse biological activities. This review aims to give an insight into the biological activities of RUT derivatives and encourage further exploration of RUT.

Ligand-based drug design of quinazolin-4(3H)-ones as breast cancer inhibitors using QSAR modeling, molecular docking, and pharmacological profiling

BACKGROUND

Breast cancer is the most common tumor among females globally. Its prevalence is growing around the world, and it is alleged to be the leading cause of cancer death. Approved anti-breast cancer drugs display several side effects and resistance during the early treatment stage. Hence, there is a need for the development of more effective and safer drugs. This research was aimed at designing more potent quinazolin-4(3H)-one molecules as breast cancer inhibitors using a ligand-based design approach, studying their modes of interaction with the target enzyme using molecular docking simulation, and predicting their pharmacological properties.

METHODS

The QSAR model was developed using a series of quinazoline-4(3H)-one derivatives by utilizing Material Studio v8.0 software and validated both internally and externally. Applicability domain virtual screening was utilized in selecting the template molecule, which was structurally modified to design more potent molecules. The inhibitive capacities of the design molecules were predicted using the developed model. Furthermore, molecular docking was performed with the EGFR target active site residues, which were obtained from the protein data bank online server (PDB ID: 2ITO) using Molegro Virtual Docker (MVD) software. SwissADME and pkCSM online sites were utilized in predicting the pharmacological properties of the designed molecules.

RESULTS

Four QSAR models were generated, and the first model was selected due to its excellent internal and external statistical parameters as follows: R2 = 0.919, R2adj = 0.898, Q2cv = 0.819, and R2pred = 0.7907. The robustness of the model was also confirmed by the result of the Y-scrambling test performed with cR2p = 0.7049. The selected model was employed to design seven molecules, with compound 4 (pIC50 = 5.18) adopted as the template. All the designed compounds exhibit better activities ranging from pIC50 = 5.43 to 5.91 compared to the template and Doruxybucin (pIC50 = 5.35). The results of molecular docking revealed better binding with the EGFR target compared with the template and Doruxybucin. The designed compounds exhibit encouraging therapeutic applicability, as evidenced by the findings of pharmacological property prediction.

CONCLUSIONS

The designed derivatives could be utilized as novel anti-breast cancer agents.

Natural Inhibitors of Cholinesterases: Chemistry, Structure-Activity and Methods of Their Analysis

This article aims to provide an updated description and comparison of the data currently available in the literature (from the last 15 years) on the studied natural inhibitors of cholinesterases (IChEs), namely, acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE). These data also apply to the likely impact of the structures of the compounds on the therapeutic effects of available and potential cholinesterase inhibitors. IChEs are hitherto known compounds with various structures, activities and origins. Additionally, multiple different methods of analysis are used to determine the cholinesterase inhibitor potency. This summary indicates that natural sources are still suitable for the discovery of new compounds with prominent pharmacological activity. It also emphasizes that further studies are needed regarding the mechanisms of action or the structure-activity correlation to discuss the issue of cholinesterase inhibitors and their medical application.

Synthesis of Quinazolinone-Fused Tetrahydroisoquinolines and Related Polycyclic Scaffolds by Iodine-Mediated sp3 C-H Amination

An iodine-mediated intramolecular sp³ C-H amination reaction producing quinazolinone-fused polycyclic skeletons from 2-aminobenzamide precursors is reported. This reaction does not use transition metals, has a broad substrate scope, and can be used on a gram scale. Under the optimal reaction conditions, a variety of quinazolinone-fused tetrahydroisoquinolines and derivatives of Rutaecarpine were synthesized from readily accessible compounds. The reaction proceeds well with crude 2-aminobenzamide derivatives, allowing for the synthesis of the products from simple 2-aminobenzoic acids and tetrahydroisoquinolines without purification of the 2-aminobenzamide intermediates. Preliminary biological experiments have identified Cereblon (CRBN) inhibitory activity and relevant anti-myeloma medicinal properties in some of these polycyclic products.

The pharmacokinetics profiles, pharmacological properties, and toxicological risks of dehydroevodiamine: A review

Dehydroevodiamine (DHE) is a quinazoline alkaloid isolated from Evodiae Fructus (EF, Wuzhuyu in Chinese, Rutaceae family), a well-known traditional Chinese medicine (TCM) which is clinically applied to treat headache, abdominal pain, menstrual pain, abdominal distension, vomiting, acid regurgitation, etc. Modern research demonstrates that DHE is one of the main components of EF. In recent years, DHE has received extensive attention due to its various pharmacological activities. This review is the first to comprehensively summarize the current studies on pharmacokinetics profiles, pharmacological properties, and toxicological risks of DHE in diverse diseases. Pharmacokinetic studies have shown that DHE has a relatively good oral absorption effect in the mean concentration curves in rat plasma and high absorption in the gastrointestinal tract. In addition, distribution re-absorption and enterohepatic circulation may lead to multiple blood concentration peaks of DHE in rat plasma. DHE possesses a wide spectrum of pharmacological properties in the central nervous system, cardiovascular system, and digestive system. Moreover, DHE has anti-inflammatory effects via downregulating pro-inflammatory cytokines and inflammatory mediators. Given the favorable pharmacological activity, DHE is expected to be a potential drug candidate for the treatment of Alzheimer's disease, chronic stress, amnesia, chronic atrophic gastritis, gastric ulcers, and rheumatoid arthritis. In addition, toxicity studies have suggested that DHE has proarrhythmic effects and can impair bile acid homeostasis without causing hepatotoxicity. However, further rigorous and well-designed studies are needed to elucidate the pharmacokinetics, pharmacological effects, potential biological mechanisms, and toxicity of DHE.

Recent advance on carbamate-based cholinesterase inhibitors as potential multifunctional agents against Alzheimer's disease

Alzheimer's disease (AD), as the fourth leading cause of death among the elderly worldwide, has brought enormous challenge to the society. Due to its extremely complex pathogeneses, the development of multi-target directed ligands (MTDLs) becomes the major strategy for combating AD. Carbamate moiety, as an essential building block in the development of MTDLs, exhibits structural similarity to neurotransmitter acetylcholine (ACh) and has piqued extensive attention in discovering multifunctional cholinesterase inhibitors. To date, numerous preclinical studies demonstrate that carbamate-based cholinesterase inhibitors can prominently increase the level of ACh and improve cognition impairments and behavioral deficits, providing a privileged strategy for the treatment of AD. Based on the recent research focus on the novel cholinesterase inhibitors with multiple biofunctions, this review aims at summarizing and discussing the most recent studies excavating the potential carbamate-based MTDLs with cholinesterase inhibition efficacy, to accelerate the pace of pleiotropic cholinesterase inhibitors for coping AD.

Synthesis, biological evaluation, and in silico study of novel library sulfonates containing quinazolin-4(3H)-one derivatives as potential aldose reductase inhibitors

A series of novel sulfonates containing quinazolin-4(3H)-one ring derivatives was designed to inhibit aldose reductase (ALR2, EC 1.1.1.21). Novel quinazolinone derivatives (1-21) were synthesized from the reaction of sulfonated aldehydes with 3-amino-2-alkylquinazolin-4(3H)-ones in glacial acetic acid with good yields (85%-94%). The structures of the novel molecules were characterized using IR, 1 H-NMR, 13 C-NMR, and HRMS. All the novel quinazolinones (1-21) demonstrated nanomolar levels of inhibitory activity against ALR2 (KI s are in the range of 101.50-2066.00 nM). Besides, 4-[(2-isopropyl-4-oxoquinazolin-3[4H]-ylimino)methyl]phenyl benzenesulfonate (15) showed higher inhibitor activity inhibited ALR2 up to 7.7-fold compared to epalrestat, a standard inhibitor. Binding interactions between ALR2 and quinazolinones have been investigated using Schrödinger Small-Molecule Drug Discovery Suite 2021-1, reported possible inhibitor-ALR2 interactions. Both in vitro and in silico study results suggest that these quinazolin-4(3H)-one ring derivatives (1-21) require further molecular modification to improve their drug nominee potency as an ALR2 inhibitor.

Synthesis of pyrimidine-containing alkaloids

This review deals with the synthesis of naturally occurring alkaloids containing partially or completely saturated pyrimidine nuclei. The interest in these compounds is associated with their structural diversity, high biological activity and toxicity. The review is divided into four parts, each of which describes a number of synthetic methodologies toward structurally different naturally occurring alkaloids containing saturated cyclic six-membered amidine, guanidine, aminal and urea (thiourea) moieties, respectively. The development of various synthetic strategies for the preparation of these compounds has remarkably increased during the past few decades. This is primarily due to the fact that some of these compounds are isolated only in limited quantities, which makes it practically impossible to study their full structural characteristics and biological activity.

A Photosensitizer-Free Radical Cascade for Synthesizing CF3-Containing Polycyclic Quinazolinones with Visible Light

Herein, we report an efficient photoinduced radical tandem trifluoromethylation/cyclization reaction of N-cyanamide alkenes for the synthesis of functionalized quinazolinones. Importantly, the reaction is carried out under mild conditions without any additional photosensitizer, metal, or extra additives. A series of trifluoromethyl quinazolinones were prepared efficiently with good yields and excellent functional group tolerance. Preliminary mechanistic experiments were conducted to indicate that the transformation proceeds via a possible mechanism involving photoexcited EDA complex and chain propagation.

Design, synthesis and biological evaluation of novel evodiamine and rutaecarpine derivatives against phytopathogenic fungi

Evodiamine and rutaecarpine are two alkaloids isolated from traditional Chinese herbal medicine Evodia rutaecarpa, which have been reported to have various biological activities in past decades. To explore the potential applications for evodiamine and rutaecarpine alkaloids and their derivatives, various kinds of evodiamine and rutaecarpine derivatives were designed and synthesized. Their antifungal profile against six phytopathogenic fungi Rhizoctonia solani, Botrytis cinerea, Fusarium graminearum, Fusarium oxysporum, Sclerotinia sclerotiorum, and Magnaporthe oryzae were evaluated for the first time. Furthermore, a series of modified imidazole derivatives of rutaecarpine were synthesized to investigate the structure-activity relationship. The results of antifungal activities in vitro showed that imidazole derivative of rutaecarpine A1 exhibited broad-spectrum inhibitory activities against R. solani, B. cinerea, F. oxysporum, S. sclerotiorum, M. oryzae and F. graminearum with EC₅₀ values of 1.97, 5.97, 12.72, 2.87 and 16.58 μg/mL, respectively. Preliminary mechanistic studies showed that compound A1 might cause mycelial abnormalities of S. sclerotiorum, mitochondrial distortion and swelling, and inhibition of sclerotia formation and germination. Moreover, the curative effects of compound A1 were 94.7%, 81.5%, 80.8%, 65.0% at 400, 200, 100, 50 μg/mL in vivo experiments, which was far more effective than the positive control azoxystrobin. Significantly, no phytotoxicity of compound A1 on oilseed rape leaves was observed obviously even at a high concentration of 400 μg/mL. Therefore, compound A1 is expected to be a novel leading structure for the development of new antifungal agents.

Therapeutic potential of quinazoline derivatives for Alzheimer's disease: A comprehensive review

Quinazolines are considered as a promising class of bioactive heterocyclic compounds with broad properties. Particularly, the quinazoline scaffold has an impressive role in the design and synthesis of new CNS-active drugs. The drug-like properties and pharmacological characteristics of quinazoline could lead to different drugs with various targets. Among CNS disorders, Alzheimer's disease (AD) is a progressive neurodegenerative disorder with memory loss, cognitive decline and language dysfunction. AD is a complex and multifactorial disease therefore, the need for finding multi-target drugs against this devastative disease is urgent. A literature survey revealed that quinazoline derivatives have diverse therapeutic potential for AD as modulators/inhibitors of β-amyloid, tau protein, cholinesterases, monoamine oxidases, and phosphodiesterases as well as other protective effects. Thus, we describe here the most relevant and recent studies about anti-AD agents with quinazoline structure which can further aid the development and discovery of new anti-AD agents.

Synthesis of 2-styryl-quinazoline and 3-styryl-quinoxaline based sulfonate esters via sp3 C-H activation and their evaluation for α-glucosidase inhibition

Synthesis of 2-styryl-quinazolines and 3-styryl-quinoxaline based sulfonates is reported via sp3 C-H functionalization in the presence of triethylamine (10 mol%). The resulting compounds were tested for the α-glucosidase enzyme inhibition...

Metal-Free Annulation of 2-Nitrobenzyl Alcohols and Tetrahydroisoquinolines toward the Divergent Synthesis of Quinazolinones and Quinazolinethiones

A simple metal-free method for the synthesis of quinazolinones from commercially available 2-nitrobenzyl alcohols and tetrahydroisoquinolines is developed. The reaction conditions were tolerant of an array of functionalities such as halogen, tertiary amine, protected alcohol, and ester groups. Under nearly identical conditions, quinazolinethiones were obtained in the presence of elemental sulfur and suitable mediators.

Therapeutic effects and potential mechanism of dehydroevodiamine on N-methyl-N'-nitro-N-nitrosoguanidine-induced chronic atrophic gastritis

BACKGROUNDS

Dehydroevodiamine (DHE) is a quinazoline alkaloid isolated from a Chinese herbal medicine, named Euodiae Fructus (Wu-Zhu-Yu in Chinese). This study aimed to investigate the therapeutic effects and potential mechanism of DHE on N-methyl-N'-nitro-N-nitrosoguanidine (MNNG)-induced chronic atrophic gastritis (CAG) based on integrated approaches.

METHODS

Therapeutic effects of DHE on serum biochemical indices and histopathology of gastric tissue in MNNG-induced CAG rats were analyzed. MNNG-induced GES-1 human gastric epithelial cell injury model was established. Cell viability and proliferation was quantified by a cell counting kit-8 assay. Cell morphology and mitochondrial membrane potential (MMP) were detected by a high content screening (HCS) assay. Cell migration and invasion were detected by a Transwell chamber. Moreover, UHPLC-Q-TOF/MS was performed to investigate the potential metabolites and signaling pathway affecting the protective effects of DHE on MNNG-induced cell migration and invasion of GES-1. Furthermore, in view of the key role of angiogenesis in the transformation of inflammation and cancer, this study explored relative mRNA and protein expression levels of HIF-1α-mediated VEGF pathway in vivo and in vitro by RT-PCR and Western Blotting, respectively.

RESULTS

The results showed that the therapeutic effects of DHE on CAG rats were presented in down-regulation serum biochemical indices and alleviating histological damage of gastric tissue. Besides, DHE has an effect on increasing cell proliferation of GES-1 cells, ameliorating MNNG-induced gastric epithelial cell damage and mitochondrial dysfunction. In addition, DHE could inhibit MNNG induced migration and invasion of GES-1 cells. Cell metabolomics analyses showed that the protective effect of DHE on GES-1 cells is mainly associated with the regulation of inflammation metabolites and energy metabolism related pathways. It was found that DHE has a regulating effect on tumor angiogenesis and can inhibit the relative gene and protein expression of HIF-1α-mediated VEGF signaling pathway.

CONCLUSIONS

The present work highlighted the role of DHE ameliorated gastric injury in MNNG-induced CAG rats in vivo and GES-1 cell migration in vitro by inhibiting HIF-1α/VEGF angiogenesis pathway. These results suggest that DHE may be the effective components of Euodiae Fructus, which provides a new agent for the treatment of CAG.

Selective Synthesis of 2-(1,2,3-Triazoyl) Quinazolinones through Copper-Catalyzed Multicomponent Reaction

We describe here our results from the copper-catalyzed three component reaction of 2-azidobenzaldehyde, anthranilamide and terminal alkynes, using Et3N as base, and DMSO as solvent. Depending on the temperature and amount of Et3N used in the reactions, 1,2,3-triazolyl-quinazolinones or 1,2,3-triazolyl-dihydroquinazolinone could be obtained. When the reactions were performed at 100 °C using 2 equivalents of Et3N, 1,2,3-triazolyl-dihydroquinazolinone was formed in 82% yield, whereas reactions carried out at 120 °C using 1 equivalent of Et3N provided 1,2,3-triazolyl-quinazolinones in moderate-to-good yields.

Effects of Natural Products on Neuromuscular Junction

Neuromuscular junction (NMJ) disorders result from damage, malfunction or absence of one or more key proteins involved in neuromuscular transmission, comprising a wide range of disorders. The most common pathology is antibody-mediated or downregulation of ion channels or receptors, resulting in Lambert-Eaton myasthenic syndrome, myasthenia gravis, and acquired neuromyotonia (Isaac's syndrome), and rarely congenital myasthenic syndromes caused by mutations in NMJ proteins. A wide range of symptomatic treatments, immunomodulating therapies, or immunosuppressive drugs have been used to treat NMJ diseases. Future research must be directed at better understanding of the pathogenesis of these diseases, and developing novel disease-specific treatments. Numerous secondary metabolites, especially alkaloids isolated from plants have been used to treat NMJ diseases in traditional and clinical practices. An ethnopharmacological approach has provided leads for identifying new treatment for NMJ diseases. In this review, we performed a literature survey in Pubmed, Science Direct, and Google Scholar to gather information on drug discovery from plant sources for NMJ disease treatments. To date, most research has focused on the effect of herbal remedies on cholinesterase inhibitory and antioxidant activities. This review provides leads for identifying potential new drugs from plant sources for the treatment of NMJ diseases.

The TSPO Ligands MGV-1 and 2-Cl-MGV-1 Differentially Inhibit the Cigarette Smoke-Induced Cytotoxicity to H1299 Lung Cancer Cells

Simple Summary

In this study, we investigated the impact of CS on various TSPO-related mitochondrial processes, and the protective ability of our novel TSPO ligands against such CS-induced cellular damages. Our results support the previously reported role of TSPO in apoptotic cell death. Moreover, the present data demonstrate the protective effect of our TSPO ligands against CS-induced cellular damage.

Abstract

TSPO is involved in cigarette smoke (CS)-induced cellular toxicity, which may result in oral and pulmonary diseases and lung cancer. H1299 lung cancer cells were exposed directly to CS. The H1299 cells were pretreated with our TSPO ligands MGV-1 and 2-Cl-MGV-1 (Ki = 825 nM for both) at a concentration of 25 µM 24 h prior to CS exposure. Cell death and apoptotic markers were measured, in addition to TSPO expression levels, ATP synthase activity, generation of reactive oxygen species (ROS), depolarization of mitochondrial membrane potential (ΔΨm), cAMP and LDH levels. Pretreatment with MGV-1 and 2-Cl-MGV-1 (25 µM), 24 h prior to CS exposure, differentially attenuated the CS-induced cellular insult as well as cell death in H1299 lung cancer cells. These protective effects included prevention of ATP synthase reversal, ROS generation, depolarization of the mitochondrial membrane and elevation in LDH. The preventive efficacy of 2-Cl-MGV-1 was superior to that achieved by MGV-1. Both ligands did not prevent the elevation in cAMP. These findings may indicate a mild protective effect of these TSPO ligands in CS-related pulmonary and keratinocyte cellular pathology.

β-Carboline as a Privileged Scaffold for Multitarget Strategies in Alzheimer's Disease Therapy

The natural β-carboline alkaloids display similarities with neurotransmitters that can be favorably exploited to design bioactive and bioavailable drugs for Alzheimer's disease (AD) therapy. Several AD targets are currently and intensively being investigated, divided in different hypotheses: mainly the cholinergic, the amyloid β (Aβ), and the Tau hypotheses. To date, only symptomatic treatments are available involving acetylcholinesterase and NMDA inhibitors. On the basis of plethoric single-target structure-activity relationship studies, the β-carboline scaffold was identified as a powerful tool for fostering activity and molecular interactions with a wide range of AD-related targets. This knowledge can undoubtedly be used to design multitarget-directed ligands, a highly relevant strategy preferred in the context of multifactorial pathology with intricate etiology such as AD. In this review, we first individually discuss the AD targets of the β-carbolines, and then we focus on the multitarget strategies dedicated to the deliberate design of new efficient scaffolds.

Risk Associated with the Use of Selected Ingredients in Food Supplements

This review focuses on four new product categories of food supplements: pre-workout, fat burner/thermogenic, brain/cognitive booster, and hormone/testosterone booster. Many food supplements have been shown to be contaminated with unauthorized substances. In some cases, the ingredients in the new categories of dietary supplements were medicinal products or new synthetic compounds added without performing clinical trials. Some of the new ingredients in dietary supplements are plant materials that are registered in the pharmacopoeia as herbal medicines. In other cases, dietary supplements may contain plant materials that have no history of human use and are often used as materials to 'camouflage' stimulants. In the European Union, new ingredients of dietary supplements, according to European Food Safety Authority or unauthorized novel food. Furthermore, selected ingredients in dietary supplements may be prohibited in sports and are recognized as doping agents by World Anti-Doping Agency.

A Multi-layered Variable Selection Strategy for QSAR Modeling of Butyrylcholinesterase Inhibitors

Background:

Alzheimer’s disease (AD), a neurological disorder, is the most common cause of senile dementia. Butyrylcholinesterase (BuChE) enzyme plays a vital role in regulating the brain acetylcholine (ACh) neurotransmitter, but in the case of Alzheimer’s disease (AD), BuChE activity gradually increases in patients with a decrease in the acetylcholine (ACh) concentration via hydrolysis. ACh plays an essential role in regulating learning and memory as the cortex originates from the basal forebrain, and thus, is involved in memory consolidation in these sites.

Methods:

In this work, we have developed a partial least squares (PLS)-regression based two dimensional quantitative structure-activity relationship (2D-QSAR) model using 1130 diverse chemical classes of compounds with defined activity against the BuChE enzyme. Keeping in mind the strict Organization for Economic Co-operation and Development (OECD) guidelines, we have tried to select significant descriptors from the large initial pool of descriptors using multi-layered variable selection strategy using stepwise regression followed by genetic algorithm (GA) followed by again stepwise regression technique and at the end best subset selection prior to development of final model thus reducing noise in the input. Partial least squares (PLS) regression technique was employed for the development of the final model while model validation was performed using various stringent validation criteria.

Results:

The results obtained from the QSAR model suggested that the quality of the model is acceptable in terms of both internal (R2= 0.664, Q2= 0.650) and external (R2 Pred= 0.657) validation parameters. The QSAR studies were analyzed, and the structural features (hydrophobic, ring aromatic and hydrogen bond acceptor/donor) responsible for enhancement of the activity were identified. The developed model further suggests that the presence of hydrophobic features like long carbon chain would increase the BuChE inhibitory activity and presence of amino group and hydrazine fragment promoting the hydrogen bond interactions would be important for increasing the inhibitory activity against BuChE enzyme.

Conclusion:

Furthermore, molecular docking studies have been carried out to understand the molecular interactions between the ligand and receptor, and the results are then correlated with the structural features obtained from the QSAR models. The information obtained from the QSAR models are well corroborated with the results of the docking study.

Merged Tacrine-Based, Multitarget-Directed Acetylcholinesterase Inhibitors 2015-Present: Synthesis and Biological Activity

Acetylcholinesterase is an important biochemical enzyme in that it controls acetylcholine-mediated neuronal transmission in the central nervous system, contains a unique structure with two binding sites connected by a gorge region, and it has historically been the main pharmacological target for treatment of Alzheimer's disease. Given the large projected increase in Alzheimer's disease cases in the coming decades and its complex, multifactorial nature, new drugs that target multiple aspects of the disease at once are needed. Tacrine, the first acetylcholinesterase inhibitor used clinically but withdrawn due to hepatotoxicity concerns, remains an important starting point in research for the development of multitarget-directed acetylcholinesterase inhibitors. This review highlights tacrine-based, multitarget-directed acetylcholinesterase inhibitors published in the literature since 2015 with a specific focus on merged compounds (i.e., compounds where tacrine and a second pharmacophore show significant overlap in structure). The synthesis of these compounds from readily available starting materials is discussed, along with acetylcholinesterase inhibition data, relative to tacrine, and structure activity relationships. Where applicable, molecular modeling, to elucidate key enzyme-inhibitor interactions, and secondary biological activity is highlighted. Of the numerous compounds identified, there is a subset with promising preliminary screening results, which should inspire further development and future research in this field.

Novel 3-Substituted-2, 3-Dihydro-2-Thioxoquinazolin-4-(1H)-one derivative as Anticonvulsants: Synthesis, Molecular Docking and Pharmacological Screening

Background:

According to the World Health Organization, 50 million people worldwide are suffering from epilepsy, making it one of the most common neurological diseases globally. 2,3 disubstituted quinazolinone-4-one derivatives endowed with various pharmacological activity, particularly having anticonvulsant action.

Objectives:

The aim of this study was to synthesize 3-Substituted-2,3-Dihydro-2-thioxoquinazolin- 4-(1H)-one derivative and evaluate for anticonvulsant activity and neurotoxicity in order to find an efficient, compound with lesser side effects.

Methods:

A novel series of 3-[4-(2-amino-5, 6-dihydro-4(substituted phenyl)-4H-1, 3-oxazin /thiazin-6yl) phenyl]-2, 3-dihyro-2-thioxoquinazolin-4(1H)-one derivatives (4a-4p) were synthesized. The structures of the synthesized compounds were assigned on the basis of spectral data (UV, IR, 1HNMR, 13CNMR and MS) and performed anticonvulsant activity against maximal electroshock test and Subcutaneous Pentylenetetrazole model. Neurotoxicity was assessed using a rotarod apparatus test. The molecular docking study was performed to assess their binding affinities towards Gamma-Aminobutyric Acid type A receptor. A quantitative estimate of drug-likeness was also performed, which calculates the molecular properties and screen the molecules based on drug-likeness rules.

Results:

Compounds 4b, 4e, 4j and 4m have shown the highest anticonvulsant activity against tonic seizure with decreased mean duration of tonic hind leg extension of 8.31, 7.35, 8.61 and 8.99 s, respectively in maximal electroshock model and increased onset time clonic convulsion duration of 94.45, 96.65, 93.51 and 91.86 s in Subcutaneous Pentylenetetrazole model. Molecular docking study revealed a better binding affinity with Gamma-Aminobutyric Acid type A receptor.

Conclusion:

The compound 4b and 4e emerged out as the pilot molecule with a better anticonvulsant activity without any neurotoxicity. The obtained results showed that compounds 4b and 4e could be useful as a template for future design, optimization, and investigation to produce more active analogs.

Stereochemistry of the methyl-idene-bridged quinazoline-iso-quinoline alkaloid 3-{[6,7-dimeth-oxy-1-(4-nitro-phen-yl)-1,2,3,4-tetra-hydro-isoquinolin-2-yl]methyl-idene}-1,2,3,9-tetra-hydro-pyrrolo-[2,1-b]quinazolin-9-one methanol monosolvate

Two potentially bioactive fragments, namely a tricyclic quinazoline derivative with an exocyclic alkene moiety and a substituted iso-quinoline, are coupled to give 3-{[6,7-dimeth-oxy-1-(4-nitro-phen-yl)-1,2,3,4-tetra-hydro-isoquinolin-2-yl]methyl-idene}-1,2,3,9-tetra-hydro-pyrrolo-[2,1-b]quinazolin-9-one. The target product crystallizes as a methanol solvate, C29H26N4O5·CH4O, and is E configured. The alternative Z isomer would necessarily imply either considerable twist about the central double bond or very unfavourable intra-molecular contacts between sterically more demanding substituents. The main residue and the co-crystallized solvent mol-ecule aggregate to discrete pairs via a classical O-H⋯O hydrogen bond with a distance of 2.8581 (7) Å between the methanol OH donor and the quinazolinone O=C acceptor.

Recent advances in the pharmacological diversification of quinazoline/quinazolinone hybrids

Due to the pharmacological activities of quinazoline and quinazolinone scaffolds, it has aroused great interest in medicinal chemists for the development of new drugs or drug candidates. The pharmacological activities of quinazoline and its related scaffolds include anti-cancer, anti-microbial, anti-convulsant, and antihyperlipidaemia. Recently, molecular hybridization technology is used for the development of hybrid analogues with improved potency by combining two or more pharmacophores of bioactive scaffolds. The molecular hybridization of various biologically active pharmacophores with quinazoline derivatives resulted in lead compounds with multi-faceted biological activity wherein specific as well as multiple targets were involved. The present review summarizes the advances in lead compounds of quinazoline hybrids and their related heterocycles in medicinal chemistry. Moreover, the review also helps to intensify the drug development process by providing an understanding of the potential role of these hybridized pharmacophoric features in exhibiting various pharmacological activities.

Recent advances in quinazoline/quinazolinone hybrid heterocycles in medicinal chemistry and their pharmacological diversification.

Synthesis, structural characterization, physicochemical properties and transformations of dehydroevodiamine and its hydrochloride salts

Five kinds of dehydroevodiamine (DHED) related crystals were harvested and transformations among evodiamine (EVO), DHED, DHED·HCl·2H₂O and rutaecarpine (RUT) were revealed.

Synthesis, Structural Studies, and α-Glucosidase Inhibitory, Antidiabetic, and Antioxidant Activities of 2,3-Dihydroquinazolin-4(1H)-ones Derived from Pyrazol-4-carbaldehyde and Anilines

A series of new quinazoline derivatives were designed and synthesized via a one-pot condensation reaction between isatoic anhydride and aromatic aldehydes with anilines using aluminum sulfate as a catalyst in refluxing ethanol. Their structures were confirmed by their physical, IR, 1H NMR, 13C NMR, and mass spectroscopy data and evaluated for some biological effects, including the antioxidant and α-glucosidase inhibitory activities as well as some in vivo hematological parameters. The ability of synthesized compounds in the inhibition of α-glucosidase was also investigated through the in silico study. The significant and important changes in some hematological tests were perceived. Notably, compound 4h showed more reducing effects on cholesterol and triglyceride levels. This molecule certainly has the potential to be developed as the antihyperlipemic compound. The tested compounds, in particular, compounds 4j and 4l, were found to be uniquely reducing blood sugar levels. The entire synthesized compounds showed the potent α-glucosidase inhibitory activity compared with acarbose as a standard material. Amongst, the compounds 4h and 4i showed the strongest enzyme inhibitory potentials than the standard drug acarbose. There was a good correlation between in vitro and in silico studies for ligands 4i and 4l. The majority of compounds presented a good radical scavenging activity, though the compound 4j exhibited the strongest activity, even to the standard of ascorbic acid. Further studies are required to determine whether these main compounds could be a potential treatment for diabetes and hyperlipidemia diseases.

Catalyst-free cyclization of anthranils and cyclic amines: one-step synthesis of rutaecarpine

An efficient synthesis of a variety of quinazolinone derivatives via a direct cyclization reaction between commercially available anthranils and cyclic amines is described. The developed transformation proceeds with the merits of high step- and atom-efficiency, a broad substrate scope, and good to excellent yields, without additional catalysts, and offers a practical way for the preparation of rutaecarpine and its derivatives with structural diversity.

Structure-based virtual screening leading to discovery of highly selective butyrylcholinesterase inhibitors with solanaceous alkaloid scaffolds

According to recent research advance, it is interesting to identify new, potent and selective inhibitors of human butyrylcholinesterase (BChE) for therapeutic treatment of both the Alzheimer's disease (AD) and heroin abuse. In this study, we carried out a structure-based virtual screening followed by in vitro activity assays, with the goal to identify new inhibitors that are selective for BChE over acetylcholinesterase (AChE). As a result, a set of new, selective inhibitors of human BChE were identified from natural products with solanaceous alkaloid scaffolds. The most active one of the natural products (compound 1) identified has an IC50 of 16.8 nM against BChE. It has been demonstrated that the desirable selectivity of these inhibitors for BChE over AChE is mainly controlled by three key residues in the active site cavity, i.e. residues Q119, A277, and A328 in BChE versus the respective residues Y124, W286, and Y337 in AChE. Based on this structural insight, future rational design of new, potent and selective BChE inhibitors may focus on these key structural differences in the active site cavity.

PI3K Inhibitors of Novel Hydrazide Analogues Linked 2-Pyridinyl Quinazolone Scaffold as Anticancer Agents

A series of novel 2-(pyridin-4-yl)quinazolin-4(3H)-ones bearing different heterocycle cores as potential PI3K inhibitors have been synthesized and evaluated via the MTT assay for their antiproliferative properties against selected HePG-2, MCF-7, and HCT116 cancer cell lines. Among them, compound 9 displayed significant activity against HePG-2 (IC50 = 60.29 ± 1.06 μM) comparable to doxorubicin as a reference anticancer drug (IC50 = 69.60 ± 1.50 μM). Kinase inhibitory assessment of target products against PI3K and docking studies revealed the promising binding affinities which match with the binding mode of the ligand, SW13 towards the active site of PI3K. Therefore, this work represents a promising matrix for developing novel potential anticancer candidates.

Total synthesis of pyrano[3,2-e]indole alkaloid fontanesine B by a double cyclization strategy

The regioselective synthesis of pyrano[3,2-e]indole alkaloid fontanesine B by two different cyclizations is described. The complete regioselectivity is controlled by the C4 Pictet–Spengler cyclization, in which an iminium ion acts as a transient directing (TDG) group. Furthermore, carbolines were constructed by a new Bischler–Napieralski-type cyclization, in which an unprecedented trichloromethyl carbamate serves as a reactive group.

The regioselective synthesis of pyrano[3,2-e]indole alkaloid fontanesine B have been accomplished by C4 Pictet–Spengler cyclization and Bischler–Napieralski-type cyclization of a trichloromethyl carbamate.

Effects of a Dehydroevodiamine-Derivative on Synaptic Destabilization and Memory Impairment in the 5xFAD, Alzheimer's Disease Mouse Model

Carboxy-dehydroevodiamine·HCl (cx-DHED) is a derivative of DHED, which improves memory impairment. Carboxyl modification increases solubility in water, indicating that its bioavailability is higher than that of DHED. Cx-DHED is expected to have better therapeutic effects on Alzheimer's disease (AD) than DHED. In this study, we investigated the therapeutic effects of cx-DHED and the underlying mechanism in 5xFAD mice, transgenic (Tg) mouse model of AD model mice. In several behavioral tests, such as Y-maze, passive avoidance, and Morris water maze test, memory deficits improved significantly in cx-DHED-treated transgenic (Tg) mice compared with vehicle-treated Tg mice. We also found that AD-related pathologies, including amyloid plaque deposition and tau phosphorylation, were reduced after the treatment of Tg mice with cx-DHED. We determined the levels of synaptic proteins, such as GluN1, GluN2A, GluN2B, PSD-95 and Rabphilin3A, and Rab3A in the brains of mice of each group and found that GluN2A and PSD-95 were significantly increased in the brains of cx-DHED-treated Tg mice when compared with the brains of Tg-vehicle mice. These results suggest that cx-DHED has therapeutic effects on 5xFAD, AD model mice through the improvement of synaptic stabilization.

Synthesis of dihydroquinazolines from 2-aminobenzylamine: N 3 -aryl derivatives with electron-withdrawing groups

The sequential N-functionalization of 2-aminobenzylamine (2-ABA) followed by cyclodehydration allowed for a straightforward and efficient synthesis of 3,4-dihydroquinazolines with N-aryl substituents bearing electron-withdrawing groups. The sequence involves an initial S_NAr displacement, N-acylation and MW-assisted ring closure. Remarkably, the uncatalyzed N-arylation of 2-ABA led to the monosubstitution product using equimolar amounts of both reagents. The individual steps were optimized achieving good to excellent overall yields of the desired heterocycles, avoiding additional protection and deprotection steps. A mechanistic interpretation for the cyclodehydration reaction promoted by trimethylsilyl polyphosphate (PPSE) is also proposed on the basis of literature data and our experimental observations.

Curtin-Hammett-Driven Intramolecular Cyclization of Heteroenyne-Allenes to Phenanthridine-Fused Quinazoliniminiums

Intramolecular cyclization of the heteroenyne-allene 2-((biphenyl-2-ylimino)methyleneamino)benzonitrile 1 to phenanthridine-fused quinazoliniminium salt PQ in the presence of a Lewis acid at room temperature involves formation of two new bonds: a C-C bond and a C-N bond. In this article, density functional theory (B3LYP and M06-2X) was employed in conjunction with 6-311G* basis set to gain insights into the mechanism of this cyclization reaction. The solvent effects were considered using Polarizable Continuum Model with nitromethane as the solvent. Our calculations show that C-C bond formation precedes the C-N bond formation. Precisely, the mechanism involves initial protonation of 1 at N_α and N_β of the carbodiimide to form rapidly equilibrating conformers of the tautomers 2a,b and 3a,b. The Curtin-Hammett principle is invoked to determine the course of the reaction from these protonated species, which predicts that the intramolecular Friedel-Crafts type N-acylation (C-C bond formation) occurs between the protonated carbodiimide and biphenyl ring of the isomer 3b to form phenanthridinium cation 6b via transition state TS3_b6_b. Once 6b is formed, it converts to its most stable tautomers 8R and 9a. Once again, the Curtin-Hammett principle suggests that intramolecular nucleophilic attack is preferred from the tautomer 8R, where phenanthridine N-atom (N_β) attacks the protonated nitrile group (C-N bond formation) and results in the formation of intermediate 11 via TS8_R11. 11 then tautomerizes to the most stable cation 13. The coordination of the latter with the chloride anion yields the phenanthridine-fused heterocyclic salt PQ with overall release of energy. The pathways involving protonation at the nitrile (N_γ) of 1 were found to be energetically unfavorable and thus insignificant to the mechanism of cyclization.

2-Aryl-3-(arylideneamino)-1,2-dihydroquinazoline-4(3H)-ones as inhibitors of cholinesterases and self-induced β-amyloid (Aβ) aggregation: biological evaluations and mechanistic insights from molecular dynamics simulations

A series of 2-aryl-3-(arylideneamino)-1,2-dihydroquinazoline-4(3H)-ones were evaluated as inhibitors of acetylcholinesterase (AChE), butyrylcholinesterase (BuChE) and self-induced β-amyloid (Aβ) aggregation. All the compounds were found to inhibit both forms of cholinesterase (IC50 in the range 4-32 μM) with some selectivity for BuChE. Most of the compounds also showed self-induced Aβ aggregation inhibitory activities, which were comparable or higher than those obtained for reference compounds, curcumin and myricetin. Docking and molecular dynamics (MD) simulation experiments suggested that the compounds are able to disrupt the dimer form of Aβ.

A one-pot synthetic approach for the construction of a thiazolo[3,2-a]benzimidazole-linked quinazoline scaffoldviapalladium-catalyzed reactions

4-(2-Substituted-[1,3]thiazolo[3,2-a]benzimidazol-3-yl)quinazolin-2-amines were prepared by the reaction of 2,4-dichloroquinazoline, terminal alkynes, secondary amines, and 1H-benzo[d]imidazole-2(3H)-thione in the presence of palladium catalyst.

Amino acids/peptides conjugated heterocycles: A tool for the recent development of novel therapeutic agents

Amino acids/peptide conjugated heterocycles represent an important class of therapeutical agents. Biologically active heterocycles are conjugated with amino acids or peptides to increase the drug resistance. Furthermore, the amino acid/peptide based drugs have low toxicity, ample bioavailability and permeability, modest potency and good metabolic and pharmacokinetic properties. Synthetic amino acid/peptides based heterocyclic conjugates constitute a promising choice for the development of new, less toxic and safer conventional pharmaceutical drugs in the near future. In this review, we discuss and highlight the recent findings of the structural features that encourage biological applications of amino acid/peptides based conjugates.

Ring-Fused Cyclic Aminals from Tetrahydro-β-carboline-Based Dipeptide Compounds

An acid- and oxidant-promoted intramolecular cyclization of a tetrahydro-β-carboline-based dipeptide has been developed to prepare new indole-fused aminoacetals. This approach involves N-acyliminium formation from readily available precursors and cyclization under mild reaction conditions. The diastereoselectivity in the formation of the products is influenced by the specific substituents of the starting reagents, which has been rationalized analyzing the energy profile of the related reactions and the relative stability of the proposed structures based on DFT computational methods.