Tetrahydroacridine Derivatives Research Articles

Synthesis, biological evaluation, and molecular modeling simulations of new heterocyclic hybrids as multi-targeted anti-Alzheimer's agents

The widespread and the recognition of the multifactorial nature of Alzheimer disease (AD) increased the demands for multi-targeted directed ligands (MTDLs) to overcome possible drug-drug interactions of the combination therapy, and to acquire superior therapeutic profile than single targeted molecules. Two main scaffolds namely: pyrazolopyridine and tetrahydroacridine (THA) were used to synthesize four different series of integrated multi-targeted synthons possessing ChE (hAChE or hBuChE), Aβ1-42 aggregation inhibition potency, in addition to optimum metal chelating capability. Structure modifications were performed to 9-amino function of THA core of tacrine and the pyrazolopyridine scaffolds linked to a variety of cyclic secondary amines directly or using amide spacers or ethylamine bridge or engaging THA with pyrazolopyridine to produce hybrid compounds. Different 9-amino substitutions improved the in vitro hAChE activity of 7- or 6,7-disubstituted THA derivatives. Compounds 16 and 28 proved to be multimodal anti-AD agents as they were potent hAChE inhibitors, in addition, they could bind with the amino acids of the peripheral anionic site (PAS) affecting Aβ aggregation and hence Aβ-dependent neurotoxicity especially compound 16 which was almost twofold more active than donepezil. Furthermore, both compounds directly inhibited Aβ1-42 self-aggregation and chelated bio-metals such as Fe2+, Zn2+ and Cu2+ preventing reactive oxygen species (ROS) generation by Aβ and its oxidative damage in the brain regions of AD patients. Compound 28 had superior privilege by its dual ChE activity resulting in better cognitive improvement. Compounds 16 and 28 showed acceptable relative safety upon hepG2 cell line and excellent BBB penetration with wide safety margin as their LD50 were higher than 120 mg/kg.

Functionalization of N-arylmaleimides by sp3 C–H bonds of hydroacridines(qinolines)

The catalyst-free sp3 C–H functionalization of tetrahydroacridine(quinolines) derivatives has been achieved using a Michael-type reaction with N-arylmaleimides. This method enables the facile synthesis of biologically important N-aryl bearing tetrahydroacridine(quinolines) moieties in a single step with high yields. The reaction occurs under non-catalytic conditions by heating of hydroacridines(quinolines) in DMSO within 4 h at 100–1200C. The reaction between starting compounds allows synthesizing (3S/4R)-3-[(3R/4S)-9-chloroacridine(quinoline)-4-yl]-1(-N-aryl)pyrrolidine-2,5-diones with a good yield. The structure of compounds was proved by spectral methods of analysis. The 1H NMR spectrum shows characteristic signals of protons of the CH-groups in acridine(quinoline) (3.4–3.5 ppm) and pyrrolidine (3.8–3.9 ppm) cycles. It is interesting to note that the main direction of the fragmentation is the Michael retro-reaction, which is accompanied by the elimination of 1-(2-nitrophenyl)-1H-pyrrole-2,5-dione and leads to the formation of m/z ions of starting chloroacridines(quinolines).

Biological assessment of new tetrahydroacridine derivatives with fluorobenzoic moiety in vitro on A549 and HT-29 cell lines and in vivo on animal model

A new series of tetrahydroacridine derivatives with the fluorobenzoyl moiety was synthesized and evaluated for cytotoxic activity against lung cancer cell lines A549 and colorectal cancer HT29. The cytotoxic activity of the compounds was compared on the somatic cell line—EAhy926. Compounds showed high cytotoxic activity on A549 cells (IC50 183.26–68.07 μM) and HT29 cells (IC50 68.41–19.70 μM), higher than controls—etoposide (IC50 451.47 μM) toward A549 and 5-fluorouracil (IC50 1626.85 μM) against HT29. Derivative 4 was the most cytotoxic to A549, whereas for the cell lines HT29 compound 6. Selected compounds showed similar cytotoxicity to the EAhy926 cell line (IC50 about 50 μM). In the hyaluronidase inhibition assay, all compounds exhibited anti-inflammatory activity, including 4 exhibiting the best inhibitory activity—IC50 of 52.27 μM when the IC50 heparin was 56.41 μM. Mathematical modeling was performed to determine LD50 after intraperitoneal, oral, intravenous and subcutaneous administration and to predict potential mutagenicity and carcinogenicity of the compounds analyzed. Obtained results showed that tested derivatives are slightly toxic compounds, and LD50 values (mg/kg) ranged from 680 to 1200 (oral rat model), the analyzed compounds have low mutagenic potential, and differences between derivatives are insignificant and very low probability of carcinogenicity. To confirm mathematical calculations, an in vivo test was carried out on a laboratory mouse model for two selected compounds. It allowed to qualify compounds: 6 to category 4 of the GHS scale, and 4 to category 3 of the GHS scale.

Synthesis of tetrahydroacridine derivatives through the Vilsmeier-Haack reaction

Synthesis of tetrahydroacridine derivatives through the Vilsmeier-Haack reaction

Synthesis of tetrahydroacridine derivatives through the Vilsmeier-Haack reaction

Synthesis of tetrahydroacridine derivatives through the Vilsmeier-Haack reaction

Novel tetrahydroacridine derivatives with iodobenzoic moieties induce G0/G1 cell cycle arrest and apoptosis in A549 non-small lung cancer and HT-29 colorectal cancer cells

A series of nine tetrahydroacridine derivatives with iodobenzoic moiety were synthesized and evaluated for their cytotoxic activity against cancer cell lines—A549 (human lung adenocarcinoma), HT-29 (human colorectal adenocarcinoma) and somatic cell line—EA.hy926 (human umbilical vein cell line). All compounds displayed high cytotoxicity activity against A549 (IC50 59.12–14.87 µM) and HT-29 (IC50 17.32–5.90 µM) cell lines, higher than control agents—etoposide and 5-fluorouracil. Structure–activity relationship showed that the position of iodine in the substituent in the para position and longer linker most strongly enhanced the cytotoxic effect. Among derivatives, 1i turned out to be the most cytotoxic and displayed IC50 values of 14.87 µM against A549 and 5.90 µM against HT-29 cell lines. In hyaluronidase inhibition assay, all compounds presented anti-inflammatory activity, however, slightly lower than reference compound. ADMET prediction showed that almost all compounds had good pharmacokinetic profiles. 1b, 1c and 1f compounds turned out to act against chemoresistance in cisplatin-resistant 253J B-V cells. Compounds intercalated into DNA and inhibited cell cycle in G0/G1 phase—the strongest inhibition was observed for 1i in A549 and 1c in HT-29. Among compounds, the highest apoptotic effect in both cell lines was observed after treatment with 1i. Compounds caused DNA damage and H2AX phosphorylation, which was detected in A549 and HT-29 cells. All research confirmed anticancer properties of novel tetrahydroacridine derivatives and explained a few pathways of their mechanism of cytotoxic action.

Multifunctional properties of novel tacrine congeners: cholinesterase inhibition and cytotoxic activity.

This review describes the synthesis of a wide range of novel tetrahydroacridine derivatives (tiocyanates, selenocyanates, ureas, selenoureas, thioureas, isothioureas, disulfides, diselenides and several tacrine homo- and hetro-hybrids). These tacrine congeners exhibit significant anticholinesterase and cytotoxic properties and may therefore be of considerable potential for the development of new drugs for the treatment of Alzheimer's disease.

Tetrahydroacridine derivatives with dichloronicotinic acid moiety as attractive, multipotent agents for Alzheimer's disease treatment

A novel series of 9-amino-1,2,3,4-tetrahydroacridine and 5,6-dichloronicotinic acid moiety were conjugated with different linkers. Afterwards new derivatives were evaluated as potential multifunctional acetylcholinesterase inhibitors (AChEIs), anti-Alzheimer's disease (AD) drug candidates. All the compounds were synthesized and tested for capacity for the inhibition of acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) enzymes. Specifically, the most promising derivative 3b (IC50 = 1.02 nM) had higher inhibitory potency compared to the reference drug, tacrine. Consequently, kinetic studies of 3b compound showed a mixed-type inhibition of both AChE and BuChE. Afterwards the best potent AChE inhibitor has been examined on amyloid β (Aβ) self-induced aggregation. Furthermore, 3b compound was tested in various concentrations and had moderate activity against Aβ aggregation. Inhibition of Aβ aggregation was 46.63% and 19.41% at 50 μM and 5 μM concentrations, respectively. Moreover, no cytotoxicity was observed for the mentioned concentrations. Therefore, 3b compound is a promising multipotent agent for the treatment of AD.

Novel tetrahydroacridine derivatives with iodobenzoic acid moiety as multifunctional acetylcholinesterase inhibitors.

New synthesized series of 9-amino-1,2,3,4-tetrahydroacridine derivatives with iodobenzoic acid moiety were studied for their inhibitory activity toward cholinesterase and against β-amyloid aggregation. All novel molecules 3a-3i interacted with both cholinesterases-acetylcholinesterase and butyrylcholinesterase-delivered nanomolar IC50 values. The structure-activity relationship showed that N-butyl moiety derivatives are stronger inhibitors toward AChE and BuChE than N-ethyl and N-propyl moieties compounds. The most potent compound toward acetylcholinesterase was inhibitor 3f (IC50 =31.2nm), and it was more active than reference drug, tacrine (IC50 =100.2 nm). Compound 3f showed strong inhibition of butyrylcholinesterase (IC50 =8.0nm), also higher than tacrine (IC50 =16.3nm). In the kinetic studies, compound 3f revealed mixed type of acetylcholinesterase inhibition. The computer modeling was carried out. The most active compound 3f was confirmed as peripheral anionic site inhibitor of acetylcholinesterase. Moreover, molecule 3f inhibited β-amyloid aggregation (at the concentration 10 μm-24.96% of inhibition, 25μm-72%, 50μm-78.44%, and 100μm-84.92%). Therefore, among all examined, compound 3f is the most promising molecule for further, more detailed research of novel multifunctional agents in the therapy of Alzheimer's disease.

Tetrahydroacridine derivatives with fluorobenzoic acid moiety as multifunctional agents for Alzheimer’s disease treatment

A novel series of 9-amino-1,2,3,4-tetrahydroacridine derivatives with 2-fluorobenzoic acid or 3-fluorobenzoic acid moiety were designed, synthesized and evaluated as inhibitors of cholinesterases and aggregation of β-amyloid. In the study target compounds were very potent inhibitors of AChE and BChE. The most promising agents had higher inhibitory potency than the reference drugs which was tacrine. Ultimately, the kinetic assay shows the most active target compound 3c against AChE. Almost all of them were more potent against BChE than AChE. Compound 3c in various concentrations was tested by aggregation experiment. Inhibition of β-amyloid aggregation was 77.32% and 80.43% at 50µM and 100µM, respectively. Therefore, compound 3c is a promising agent for the treatment of AD.

Novel tetrahydroacridine and cyclopentaquinoline derivatives with fluorobenzoic acid moiety induce cell cycle arrest and apoptosis in lung cancer cells by activation of DNA damage signaling

Lung cancer is still the leading cause of cancer-related death worldwide, indicating a necessity to develop more effective therapy. Acridine derivatives are potential anticancer agents due to their ability to intercalate DNA as well as inhibit enzymes involved in replication and transcription. Recently, we have evaluated anticancer activity of 32 novel acridine-based compounds. We found that the most effective were tetrahydroacridine and cyclopentaquinoline derivatives with fluorobenzoic acid containing eight and nine carbon atoms in the aliphatic chain. The aim of this study was to determine the molecular mechanisms of compounds-induced cell cycle arrest and apoptosis in human lung adenocarcinoma cells. All compounds activated Ataxia telangiectasia mutated kinase and phosphorylated histone H2A.X at Ser139 indicating DNA damage. Treatment of cells with the compounds increased phosphorylation and accumulation of p53 that regulate cell cycle as well as apoptosis. All compounds induced G0/1 cell cycle arrest by phosphorylation of cyclin-dependent kinase 2 at Tyr15 resulting in attenuation of the kinase activity. In addition, cyclopentaquinoline derivatives induced expression of cyclin-dependent kinase 2 inhibitor, p21; however, tetrahydroacridine derivatives had no significant effect on p21. Moreover, all compounds decreased the mitochondrial membrane potential accompanied by increased expression of Bax and down-regulation of Bcl-2, suggesting activation of the mitochondrial pathway. All compounds also significantly attenuated the migration rates of lung cancer cells. Collectively, our findings suggest a central role of activation of DNA damage signaling in response to new acridine derivatives treatment to induce cell cycle arrest and apoptosis in cancer cells and provide support for their further development as potential drug candidates.

Assessment of some synthesized novel 9-substituted tetrahydroacridine derivatives in diabetic disease management in rats

Background and objective 9-Substituted 1,2,3,4-tetrahydroacridine derivatives, especially those bearing substituted aliphatic or aromatic amino groups at the position 9, have been widely used for treating some chronic diseases because of their role as acetylcholine esterase inhibitors. Therefore, some new substituted tetrahydroacridine derivatives were synthesized to investigate their efficiency as antidiabetic agents in vivo. Materials and methods Some new substituted tetrahydroacridine derivatives hybridized at their position 9 with nitrogen, oxygen, and/or sulfur heterocycles or sulfa drugs starting from the known intermediate compound 9-chlorotetrahydroacridine were synthesized. Biologically, these compounds were investigated for antidiabetic potentials using Wistar rats. Diabetes was induced using streptozotocin (45 mg/kg) and then biochemical assays and histopathological examinations were applied to assess the therapeutic efficiency and safety margins of these compounds. Results and discussion Biochemical and histopathological examinations demonstrated the efficiency and safety margins of these compounds in vivo. Different biochemical analyses and histopathological examinations were estimated in diabetic and treated groups as compared with the healthy one. Data listed in this study showed an acceptable improvement percentage in glucose level and α-amylase, liver function enzymes (glutamic pyruvic transaminase and glutamic oxaloacetic transaminase), and lipid profile (triglyceride, low-density lipoprotein, total cholesterol) parameters after treatment with new synthetic compounds. Histopathological examination showed regeneration of treated groups. 9-Sulfadiazine-tetrahydroacridine (9-SDTHA) derivative (2b) was the most safe and efficient compound. The superiority of this compound may be because of the presence of a pyrimidine ring, which is the main constituent of DNA and RNA structure. These compounds could be suggested as antidiabetic agents.

Erratum: Assessment of some synthesized novel 9-substituted tetrahydroacridine derivatives in diabetic disease management in rats

Erratum: Assessment of some synthesized novel 9-substituted tetrahydroacridine derivatives in diabetic disease management in rats

Synthesis, biological evaluation and molecular modeling of new tetrahydroacridine derivatives as potential multifunctional agents for the treatment of Alzheimer’s disease

A novel series of 9-amino-1,2,3,4-tetrahydroacridine derivatives with 4-dimethylaminobenzoic acid moiety was synthesized and tested towards inhibition of cholinesterases and amyloid β aggregation. Target compounds were designed as dual binding site cholinesterase inhibitors able to bind to both the catalytic and the peripheral site of the enzyme and therefore potentially endowed with other properties. The obtained derivatives were very potent inhibitors of both cholinesterases (EeAChE, EqBChE) with IC50 values ranging from sub-nanomolar to nanomolar range, and the inhibitory potency of the most promising agents was higher than that of the reference drugs (rivastigmine and tacrine). The kinetic studies of the most active compound 3a revealed competitive type of AChE inhibition. Moreover, all target compounds were more potent inhibitors of human AChE than tacrine with the most active compound 3b (IC50=19nM). Compound 3a was also tested and displayed inhibitory potency against AChE-induced Aβ 1–42 aggregation (80.6% and 91.3% at 50μM and 100μM screening concentration, respectively). Moreover, cytotoxicity assay performed on A549 cells did not indicate toxicity of this agent. Compound 3a is a promising candidate for further development of novel multi-functional agents in the therapy of AD.

Novel tetrahydroacridine derivatives inhibit human lung adenocarcinoma cell growth by inducing G1 phase cell cycle arrest and apoptosis

Lung cancer is not only the most commonly diagnosed cancers worldwide but it is still the leading cause of cancer-related death. Acridine derivatives are a class of anticancer agents with the ability to intercalate DNA and inhibit topoisomerases. The aim of this study was to evaluate the effect of sixteen new tetrahydroacridine derivatives on the viability and growth of human lung adenocarcinoma cells. We compared anticancer activity of a series of eight compounds with 4-fluorobenzoic acid and eight compounds with 6-hydrazinonicotnic acid differed from each other in length of the aliphatic chain containing from 2 to 9 carbon atoms. Interestingly, tetrahydroacridine with 4-fluorobenzoic acid (compounds 9–16) showed higher anticancer activity than derivatives with 6-hydrazinonicotnic acid (compounds 1–8) and their efficacy was correlated with increasing number of carbon atoms in the aliphatic chain. The results showed that inhibition of cancer cell growth by the most effective compounds 15 and 16 was associated with induction of G1 phase cell cycle arrest followed by caspase-3 dependent apoptosis. Our findings suggest that tetrahydroacridine with 4-fluorobenzoic acid containing 8 and 9 carbon atoms may be potential candidate for treatment of lung cancer.

Development of potent autophagy inhibitors that sensitize oncogenic BRAF V600E mutant melanoma tumor cells to vemurafenib

Autophagy is a dynamic cell survival mechanism by which a double-membrane vesicle, or autophagosome, sequesters portions of the cytosol for delivery to the lysosome for recycling. This process can be inhibited using the antimalarial agent chloroquine (CQ), which impairs lysosomal function and prevents autophagosome turnover. Despite its activity, CQ is a relatively inadequate inhibitor that requires high concentrations to disrupt autophagy, highlighting the need for improved small molecules. To address this, we screened a panel of antimalarial agents for autophagy inhibition and chemically synthesized a novel series of acridine and tetrahydroacridine derivatives. Structure-activity relationship studies of the acridine ring led to the discovery of VATG-027 as a potent autophagy inhibitor with a high cytotoxicity profile. In contrast, the tetrahydroacridine VATG-032 showed remarkably little cytotoxicity while still maintaining autophagy inhibition activity, suggesting that both compounds act as autophagy inhibitors with differential effects on cell viability. Further, knockdown of autophagy-related genes showed no effect on cell viability, demonstrating that the ability to inhibit autophagy is separate from the compound cytotoxicity profiles. Next, we determined that both inhibitors function through lysosomal deacidification mechanisms and ultimately disrupt autophagosome turnover. To evaluate the genetic context in which these lysosomotropic inhibitors may be effective, they were tested in patient-derived melanoma cell lines driven by oncogenic BRAF (v-raf murine sarcoma viral oncogene homolog B). We discovered that both inhibitors sensitized melanoma cells to the BRAF V600E inhibitor vemurafenib. Overall, these autophagy inhibitors provide a means to effectively block autophagy and have the potential to sensitize mutant BRAF melanomas to first-line therapies.

Synthesis of certain tetrahydroacridine derivatives of anticipated medicinal value

This study aims at the synthesis and evaluation of the chemotherapeutic activity of a number of 9-substituted tetrahydroacridine derivatives. The starting material, acridine hydrazide, could be prepared through the interaction between cyclohexanone and anthranilic acid, then chlorination of the product, then condensation of the last compound with hydrazine hydrate. The structures of the new compounds were established by IR, 1H NMR, MS spectra, and elemental analysis in certain cases. Antitumor activities as a trial to obtain more effective and less toxic agents were evaluated. The antitumor activity results indicated that the selected tetrahydroacridine derivatives showed antitumor activity against the liver cancer (HEPG2) tumor cell line tested, but with varying intensities in comparison to the known anticancer drugs, 5-fluorouracil and doxorubicin. It was found that compound VIb was the most active and induced a marked growth inhibition (0.694 μg/ml concentration) in a dose-dependent manner against liver cancer (HEPG2), while compound XVIIIa was second in regards to the growth inhibition activity (2.97 μg/ml concentration).

ChemInform Abstract: Broensted Acid‐Catalyzed Enantioselective Friedlaender Condensations: Achiral Amine Promoter Plays Crucial Role in the Stereocontrol.

AbstractUse of 2‐naphthylamine as promoter in the enantioselective Friedlaender condensation of o‐aminobenzaldehydes with p‐substituted cyclohexanones provides access to tetrahydroacridine derivatives in high yields and excellent enantioselectivity (up to 95%).

Synthesis and characterization of quinoline derivatives via the Friedländer reaction

A rapid and efficient method for the synthesis of various poly-substituted quinolines has been developed via the Friedländer condensation of 2-aminoarylaldehyde with a carbonyl compound containing a reactive α-methylene group in the presence of sodium ethoxide (10 mol %). The new tetrahydroacridine derivatives and 11 H-indeno[1,2- b]quinolines were synthesized in high yield with sodium ethoxide as a catalyst via the Friedländer reaction. The conditions of reaction were discussed and the possible reaction mechanism was proposed.

Thiol-dependent inhibition of RNA synthesis in vitro by acridines. Structure-inhibition relationships

In the presence of sulfhydryl compounds and anticancer drug, 1-nitro-9-aminoalkylacridine derivative, forms with DNA irreversible, probably covalent, complexes of decreased template properties. Five 9-substituted 1-nitro-9-aminoacridine derivatives of cytostatic activity show irreversible thiol-dependent inhibitory effects on the RNA synthesis in vitro system while equal inhibition is observed both in the presence and in the absence of dithiothreitol with biologically inactive analogues of nitracrine. In the absence of sulfhydryl compounds the inhibition depends on the planarity of the acridine ring. Hence, both 1-nitro-9-aminoalkylacridine and tetrahydroacridine derivatives show low inhibitory effect.