Synthesis and biological evaluation of some thiazole derivatives as new cholinesterase inhibitors

The therapeutic value of thiazole and thiazolidine derivatives in Alzheimer's disease: a systematic literature review

Background and purpose

Alzheimer's disease (AD) is a common neurodegenerative disease and the fifth leading cause of death among the elderly. The development of drugs for AD treatment is based on inhibiting cholinesterase (ChE) activity and inhibiting amyloid-beta peptide and tau protein aggregations. Many in vitro findings have demonstrated that thiazole-and thiazolidine-based compounds have a good inhibitory effect on ChE and other elements involved in the AD pathogenicity cascade.

Experimental approach

In the present review, we collected available documents to verify whether these synthetic compounds can be a step forward in developing new medications for AD. A systematic literature search was performed in major electronic databases in April 2021. Twenty-eight relevant in vitro and in vivo studies were found and used for data extraction.

Findings/Results

Findings demonstrated that thiazole-and thiazolidine-based compounds could ameliorate AD's pathologic condition by affecting various targets, including inhibition of ChE activity, amyloid-beta, and tau aggregation in addition to cyclin-dependent kinase 5/p25, beta-secretase-1, cyclooxygenase, and glycogen synthase kinase-3β.

Conclusion and implications

Due to multitarget effects at micromolar concentration, this review demonstrated that these synthetic compounds could be considered promising candidates for developing anti-Alzheimer drugs.

Synthesis and molecular docking simulation of new benzimidazole-thiazole hybrids as cholinesterase inhibitors

Dementia is a cognitive disturbance that is generally correlated with central nervous system diseases, especially Alzheimer's disease. The limited number of medications available is insufficient to improve the lifestyle of the patients suffering from this disease. Thus, new benzimidazole-thiazole hybrids (3-10) were designed and synthesized as acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory agents. The in vitro evaluation displayed that the derivatives 4b, 4d, 5b, 6a, 7a, and 8b demonstrated dual inhibitory efficiency against both AChE with IC50 ranging from 4.55 to 8.62 µM and BChE with IC50 ranging from 3.50 to 8.32 µM. By analyzing the Lineweaver-Burk plot, an uncompetitive form of inhibition was determined for the highly active compound 4d, revealing its inhibition type. The human telomerase reverse transcriptase-immortalized retinal pigment epithelial cell line was used to ensure the safety of the most potent cholinesterase inhibitors. Furthermore, compounds 4b, 4d, 5b, 6a, 7a, and 8b were evaluated for their neuroprotective and antioxidant properties, as well as their ability to suppress COX-2. The results demonstrated that compounds 4d, 5b, and 8b presented significant neuroprotection efficiency against H2 O2 -induced damage in SH-SY5Y cells with % cell viability of 67.42 ± 7.90%, 62.51 ± 6.71%, and 72.61 ± 8.10%, respectively, while the tested candidates did not reveal significant antioxidant activity. Otherwise, compounds 4b, 6a, 7a, and 8b displayed outstanding COX-2 inhibition effects with IC50 ranging from 0.050 to 0.080 μM relative to celecoxib (IC50  = 0.050 µM). In addition, molecular docking was carried out for the potent benzimidazole-thiazole hybrids with the active sites of both AChE (PDB ID: 4EY7) and BChE (PDB code: 1P0P). The tested candidates fit well in the active sites of both portions, with docking scores ranging from -8.65 to -6.64 kcal/mol (for AChE) and -8.71 to -7.73 kcal/mol (for BChE). In silico results show that the synthesized benzimidazole-thiazole hybrids have good physicochemical and pharmacokinetic properties with no Lipinski rule violations. The preceding results exhibited that compound 4d could be used as a new template for developing more significant cholinesterase inhibitors in the future.

Synthesis and evaluation of novel xanthene-based thiazoles as potential antidiabetic agents

A series of xanthene-based thiazoles was synthesized and characterized by different scpectroscopic methods, i.e. Proton nuclear magnetic resonance (¹ H NMR), carbon nuclear magnetic resonance (¹³ C NMR), infrared spectroscopy, carbon hydrogen nitrogen analysis, and X-ray crystallography. The inhibition potencies of 18 newly synthesized thiazole derivatives were investigated on the activities of acetylcholinesterase (AChE), butyrylcholinesterase (BChE), α-amylase (α-Amy), and α-glycosidase (α-Gly) enzymes in accordance with their antidiabetic and anticholinesterase ability. The synthesized compounds have the highest inhibition potential against the enzymes at low nanomolar concentrations. Among the 18 newly synthesized molecules, 3b and 3p were superior to the known commercial inhibitors of the enzymes and have a much more effective inhibitory potential, with IC₅₀ : 2.37 and 1.07 nM for AChE, 0.98 and 0.59 nM for BChE, 56.47 and 61.34 nM for α-Gly, and 152.48 and 124.84 nM for α-Amy, respectively. Finally, the optimized 18 compounds were subjected to molecular docking to describe the interaction between thiazole derivatives and AChE, BChE, α-Amy, and α-Gly enzymes in which important interactions were monitored with amino acid residues of each target enzyme.

2-amino thiazole derivatives as inhibitors of some metabolic enzymes: An In Vitro and In Silico study

The thiazole derivatives are desirable compounds in the evaluation of their biological activities such as antiprotozoal antibacterial, antifungal, antituberculosis. Considering the medical application potential of 2-amino thiazole compounds, we aimed to determine the effects of 2-amino thiazole derivatives on the activities of carbonic anhydrase I-II isoenzymes, acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). Among the chemicals we used in our study, 2-Amino-4-(4-chlorophenyl)thiazole compound exhibited the best inhibition against hCA I with K_i of 0.008±0.001 μM. The 2-Amino-4-(4-bromophenyl)thiazole compound exhibited the best inhibition against hCA II, AChE and BChE with K_i of 0.124±0.017 μM, 0.129±0.030 μM and 0.083±0.041 μM, respectively. Molecular docking analysis showed that compound 2-Amino-4-(5,6,7,8-tetrahydro-2-naphthyl)thiazole had the highest inhibitory potency against hCA I, hCA II, AChE, BChE with the estimated binding energy of -6.75 , -7.61, -7.86, -7.96 kcal/mol, respectively. This article is protected by copyright. All rights reserved.

Thiazole: A Versatile Standalone Moiety Contributing to the Development of Various Drugs and Biologically Active Agents

For many decades, the thiazole moiety has been an important heterocycle in the world of chemistry. The thiazole ring consists of sulfur and nitrogen in such a fashion that the pi (π) electrons are free to move from one bond to other bonds rendering aromatic ring properties. On account of its aromaticity, the ring has many reactive positions where donor–acceptor, nucleophilic, oxidation reactions, etc., may take place. Molecules containing a thiazole ring, when entering physiological systems, behave unpredictably and reset the system differently. These molecules may activate/stop the biochemical pathways and enzymes or stimulate/block the receptors in the biological systems. Therefore, medicinal chemists have been focusing their efforts on thiazole-bearing compounds in order to develop novel therapeutic agents for a variety of pathological conditions. This review attempts to inform the readers on three major classes of thiazole-bearing molecules: Thiazoles as treatment drugs, thiazoles in clinical trials, and thiazoles in preclinical and developmental stages. A compilation of preclinical and developmental thiazole-bearing molecules is presented, focusing on their brief synthetic description and preclinical studies relating to structure-based activity analysis. The authors expect that the current review may succeed in drawing the attention of medicinal chemists to finding new leads, which may later be translated into new drugs.

Pharmacological report of recently designed multifunctional coumarin and coumarin-heterocycle derivatives

Coumarin is a naturally available molecule and has been identified as a potent pharmacophore due to its pharmacological activity. Because of this, coumarin has been exploited synthetically to prepare a wide range of derivatives. In fact, most coumarin derivatives have been found to be less toxic, which is the most essential property for a drug molecule. Such molecules are being prepared for therapeutic use as broad-spectrum pharmacological agents. Microbial diseases including viral diseases have become very common and are responsible for many deaths worldwide. In particular, microbial drug resistance is a problem that needs to be tackled in an effective manner. Also, for Alzheimer's disease, which affects most elderly persons, no efficient chemotherapy exists. In addition, although diabetes, a metabolic syndrome, can be treated with many drugs, there is no complete cure. Thus, more potent antidiabetic agents are required for the management of diabetes. Likewise, for the treatment of a wide range of ailments caused by microbes, genetic factors, or lifestyle-related factors, an efficient drug regimen is needed. In view of this, coumarin derivatives are designed and evaluated. Here, coumarin derivatives that have been reported recently are compiled, classified and evaluated critically. This study briefly takes the structure-activity relationship into consideration and suggests the next suitable step. With a focus on the most potent molecules, the pharmacological activity of the evaluated molecules is described.

Novel metabolic enzyme inhibitors designed through the molecular hybridization of thiazole and pyrazoline scaffolds

New hybrid thiazolyl-pyrazoline derivatives (4a-k) were obtained through a facile and versatile synthetic procedure, and their inhibitory effects on the human carbonic anhydrase (hCA) isoforms I and II as well as on acetylcholinesterase (AChE) were determined. All new thiazolyl-pyrazolines showed activity at nanomolar levels as hCA I, hCA II, and AChE inhibitors, with K_I values in the range of 13.35-63.79, 7.01-115.80, and 17.89-48.05 nM, respectively. 1-[4-(4-Cyanophenyl)thiazol-2-yl]-3-(4-piperidinophenyl)-5-(4-fluorophenyl)-2-pyrazoline (4f) and 1-(4-phenylthiazol-2-yl)-3-(4-piperidinophenyl)-5-(4-fluorophenyl)-2-pyrazoline (4a) against hCAs and 1-[4-(4-chlorophenyl)thiazol-2-yl]-3-(4-piperidinophenyl)-5-(4-fluorophenyl)-2-pyrazoline (4d) and 1-[4-(4-nitrophenyl)thiazol-2-yl]-3-(4-piperidinophenyl)-5-(4-fluorophenyl)-2-pyrazoline (4b) against AChE were identified as highly potent inhibitors, superior to the standard drugs, acetazolamide and tacrine, respectively. Compounds 4a-k were also evaluated for their cytotoxic effects on the L929 mouse fibroblast (normal) cell line. Moreover, a comprehensive ligand-receptor interaction prediction was performed using the ADME-Tox, Glide XP, and MM-GBSA modules of the Schrödinger Small-Molecule Drug Discovery Suite to elucidate the potential binding modes of the new hybrid inhibitors against these metabolic enzymes.

Characterization of the bioactivities of an ethanol extract and some of its constituents from the New Zealand native mushroom Hericium novae-zealandiae

In this study, we investigated the potential bioactivities of an ethanol extract of Hericium novae-zealandiae and four of its constituents, namely hericenone C, hericene B, ergosterol and ergosterol peroxide. The proliferation of three prostate cancer cell lines, namely DU145, LNCaP and PC3, was evaluated after treatment with the extract and constituents. It was found that both the ethanol extract and ergosterol peroxide possess anti-proliferative activities to the three prostate cancer cell lines. Ergosterol peroxide was considered likely to be one of the major compounds responsible for the anti-proliferative effect of the ethanol extract. Subsequently, the results of RT-qPCR assay showed two possible mechanisms for these anti-proliferative activities. One is apoptosis, supported by the up-regulation of CASP3, CASP8, CASP9, and an increase in the ratio of Bax/Bcl2. The other is anti-inflammation, indicated by the down-regulation of IL6 and up-regulation of IL24. The ethanol extract also exhibited antioxidant and AChE inhibitory (though weak) activities. However, none of the four compounds were found to account for these latter two activities. This is the first report of the bioactivities, and the corresponding active ingredients of lipophilic constituents from H. novae-zealandiae.

Assessment of In Vitro Bioactivities of Polysaccharides Isolated from Hericium Novae-Zealandiae

The objective of this study was to investigate the potential effect of the polysaccharides isolated from Hericium novae-zealandiae, a native New Zealand fungus, on the in vitro proliferation of prostate cancer cell lines, gene expression, acetylcholinesterase (AChE) activity, and oxidation. One water-soluble and two alkali-soluble polysaccharide fractions were isolated from H. novae-zealandiae. The proliferation of the prostate cancer cell lines DU145, LNCaP, and PC3 was evaluated following treatment with these polysaccharide fractions. It was found that the polysaccharides possess anti-proliferative activity on LNCaP and PC3 cells, with a 50% growth inhibition (IC₅₀) value as low as 0.61 mg/mL in LNCaP. Subsequently, it was determined through via RT-qPCR assay that apoptosis was one of the possible mechanisms responsible for the anti-proliferative activity in LNCaP. This was supported by the up-regulation of CASP3, CASP8, and CASP9. An alternative, discovered in PC3, was revealed to be anti-inflammation, which was hinted at by the down-regulation of IL6 and up-regulation of IL24. The polysaccharides also exhibited antioxidant and weak AChE inhibitory activities. This is the first report on the potential health benefits of polysaccharides prepared from the New Zealand fungus, H. novae-zealandiae.

Synthesis and Evaluation of a New Series of Thiazolyl-pyrazoline Derivatives as Cholinesterase Inhibitors

Objectives

In recent years, the design of anticholinesterase agents based on molecular hybridization of pharmacologically active scaffolds has attracted a great deal of interest in medicinal chemistry. For this purpose, we aimed to design and synthesize anticholinesterase agents based on the molecular hybridization of thiazole and pyrazoline scaffolds.

Materials and Methods

New thiazolyl-pyrazoline derivatives were synthesized via the ring closure reaction of 3-(2-furyl)-5-(1,3-benzodioxol-5-yl)-1-thiocarbamoyl-4,5-dihydro-1H-pyrazole with 2-bromo-1-arylethanone derivatives. The compounds were investigated for their inhibitory effects on AChE and BuChE using a modification of Ellman's spectrophotometric method. As a part of this study, the compliance of the compounds to Lipinski's rule of five was evaluated. The physicochemical parameters (log P, TPSA, nrotb, molecular weight, number of hydrogen bond donors and acceptors, molecular volume) were calculated using Molinspiration software.

Results

2-[5-(1,3-Benzodioxol-5-yl)-3-(2-furyl)-4,5-dihydro-1H-pyrazol-1-yl]-4-(naphthalen-2-yl)thiazole was found to be the most effective AChE inhibitor (38.5±2.85%), whereas 2-[5-(1,3-benzodioxol-5-yl)-3-(2-furyl)-4,5-dihydro-1H-pyrazol-1-yl]-4-(4-fluorophenyl)thiazole was found as the most potent BuChE inhibitor (43.02±2.71%) in this series. These compounds only violated one parameter of Lipinski's rule of five. On the basis of Lipinski's rule, they were expected to have reasonable oral bioavailability.

Conclusion

In the view of this study, the structural modification of the identified compounds is on-going for the generation of new cholinesterase inhibitors with enhanced efficacy.

Synthesis, Crystal Structure and Biological Evaluation of Novel 2-Phenylthiazole Derivatives as Butyrylcholinesterase Inhibitors

To find novel butyrylcholinesterase inhibitors, three novel 2-phenylthiazole derivatives were synthesised. The synthesised compounds were characterised by NMR and single-crystal X-ray diffraction analysis. Hirshfeld surface analysis and two-dimensional fingerprint plots of the compounds were used as a theoretical approach to assess the driving force for crystal structure formation via the intermolecular interactions in the crystal lattices of the synthesised compounds. Among the three compounds, N-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro- 1H-pyrazol-4-yl)-2-(4-methoxyphenyl)thiazole-4-carboxamide showed the best butyrylcholinesterase-inhibition activity with an IC50 value of 75.12 μM. A docking study demonstrated that this compound interacts with the peripheral anionic site of butyrylcholinesterase.

Synthesis and Biological Evaluation of Novel Piperazine Containing Hydrazone Derivatives

Some hydrazone derivatives were synthesized and their potential anticholinesterase activities were examined. A series of eleven new compounds of N′-(2,4-disubstitutedbenzylidene)-2-(4-(4-nitrophenyl)piperazin-1-yl)acetohydrazide derivatives were obtained via reaction of 2-[4-(4-nitrophenyl)piperazin-1-yl]acetohydrazide with aromatic aldehydes. The chemical structures of the compounds were enlightened by FT-IR,1H-NMR,13C-NMR, and HRMS (ESI) spectral data. The inhibition potency of the compounds3a–kagainst AChE and BuChE was measured and evaluated using a modification of Ellman’s spectrophotometric method. Among the tested compounds, compound3cwas assigned to be the most active derivative. Galantamine was used as a standard drug.