Current Pharmaceutical Research on the Significant Pharmacophore Mannich bases in Drug Design.

A multitude of distinct Mannich bases have been synthesized and evaluated as potential therapeutics for a wide variety of diseases and medical conditions, either in the form of prodrugs or as molecules that trigger a biological response from specific targets. The Mannich reaction has been utilized to enhance the biological activity of numerous compounds, resulting in notable progress in various areas such as anticonvulsant, antimalarial, anticancer, anti-inflammatory, antiproliferative, antibacterial, antimicrobial, antitubercular, antiprotozoal, topoisomerases I and II inhibition, α-glucosidase inhibition, carbonic anhydrase inhibition, as well as research related to anti-Alzheimer's disease and anti-Parkinson's disease. Bioactive semisynthetic Mannich bases derived from natural compounds such as chalcone, curcumin, and thymol have also been identified. Pharmaceutical compounds characterized by low solubility may encounter challenges related to their oral bioavailability, half-life, distribution within tissues, rapid metabolism, toxicity, and various other relevant variables. Mannich bases have the ability to undergo protonation under physiological circumstances, facilitating interactions between ligands and receptors, and enhancing their solubility in water. The experimental findings indicate that the solubility of Mannich base prodrugs is higher compared to that of the parent compound. The use of the multicomponent Mannich reaction has been established as a valuable synthetic methodology for the construction of multifunctional compounds through the application of diverse synthetic strategies under varying reaction conditions. The continuous investigation of synthetic techniques for Mannich reactions involves several approaches, such as employing protocols in aquatic environments, utilizing catalysts that are both biodegradable and reusable, exploring the use of ionic liquids, investigating solvent-free and/or catalyst-free media, and exploring reaction conditions involving microwave and ultrasound irradiation. Consequently, the Mannich reaction has emerged as a powerful technique in the field of medicinal chemistry. It is utilized for the creation of new chemical compounds that possess diverse and attractive biologic features. Additionally, this reaction is employed to alter the physicochemical properties of a potential drug candidate, thereby influencing its bioavailability, efficacy, and pharmacological activity. Due to their favorable bioactivities and synthesis techniques, Mannich bases remain a subject of ongoing attention in the field of medicinal/pharmaceutical chemistry.

Investigation of carbonic anhydrase inhibitory effects and cytotoxicities of pyrazole-based hybrids carrying hydrazone and zinc-binding benzenesulfonamide pharmacophores.

Pyrazole-based carbohydrazone hybrids have been considered to be a remarkable class of compounds in pharmaceutical chemistry. Here, we reported bioactivities of 4-(3-(2-(arylidene)hydrazin-1-carbonyl)-5-phenyl-1H-pyrazol-1-yl)benzenesulfonamides (1-27) towards CA isoenzymes (hCA I, hCA II, hCA IX) and human oral squamous cell carcinoma cell line. Compounds 19 (Ki = 10.1 nM, hCA I/hCA IX = 749.6), 22 (Ki = 18.5 nM, hCA I/hCA IX = 429.2), 26 (Ki = 14.5 nM, hCA I/hCA IX = 596.9), 27 (Ki = 21.5 nM, hCA I/hCA IX = 413.1) were more potent and selective inhibitors of cancer-associated hCA IX isoenzyme. Compounds 22 and 26 were also found to be approximately three times more selective hCA IX inhibitors over off-target hCA II at low nanomolar. Compounds 19, 22, 23, 24, and 26 with IC50 of 1.6-1.7 µM showed potent cytotoxicity against human oral squamous cell carcinoma cell line as compared with human gingival fibroblast, producing the tumor-specificity value over 100. This was due to its cytostatic growth inhibition accompanied by a slight but significant dose-dependent increase in cell shrinkage and subG1 cell accumulation and marginal activation of caspase 3 substrates. Bioassay results showed that carbohydrazone-based hybrids could be useful candidates to design novel anticancer compounds and selective carbonic anhydrase inhibitors.

Quinazolinone-based benzenesulfonamides with low toxicity and high affinity as monoamine oxidase-A inhibitors: Synthesis, biological evaluation and induced-fit docking studies.

The research in selective monoamine oxidases (MAO-A and MAO-B) inhibitors has been increased due to their therapeutic value for neurodegenerative diseases. In this study, 4-((2-(aryl)-4-oxoquinazolin-3(4H)-yl)amino)benzenesulfonamides were synthesized and their MAOs inhibition potentials were investigated applying in vitro fluorometric technique. The most potent compounds 7 and 8 against MAO-A had IC50 values of 0.058 ± 0.002 and 0.094 ± 0.003 µM, respectively, while the reference moclobemide had an IC50 value of 6.061 µM. Compounds 7 (>1724 times) and 8 (>1063 times) more selective and reversible inhibitors of MAO-A rather than MAO-B. Toxicity studies of 7 (IC50 = 210.23 µM) and 8 (IC50 = 259.27 µM) showed that compounds can be considered as non-toxic towards SH-SY5Y cell line at their effective concentrations against MAO-A. In silico docking simulations successfully explained the observed activities and also highlighted structural water molecules to play a key role in the ligand-enzyme interactions. Calculated molecular descriptors are also obeying Lipinski's rule of five and brain/blood partition coefficients, a critical parameter in neurodegenerative diseases. These reversible inhibitors can have considerable advantages compared to irreversible inhibitors which may possess serious pharmacological side effects.

Monoamine Oxidase (MAO) as a Potential Target for Anticancer Drug Design and Development.

Monoamine oxidases (MAOs) are oxidative enzymes that catalyze the conversion of biogenic amines into their corresponding aldehydes and ketones through oxidative deamination. Owing to the crucial role of MAOs in maintaining functional levels of neurotransmitters, the implications of its distorted activity have been associated with numerous neurological diseases. Recently, an unanticipated role of MAOs in tumor progression and metastasis has been reported. The chemical inhibition of MAOs might be a valuable therapeutic approach for cancer treatment. In this review, we reported computational approaches exploited in the design and development of selective MAO inhibitors accompanied by their biological activities. Additionally, we generated a pharmacophore model for MAO-A active inhibitors to identify the structural motifs to invoke an activity.

Synthesis and biological evaluation of new pyrazolebenzene-sulphonamides as potential anticancer agents and hCA I and II inhibitors.

Cancer is a disease characterized by the continuous growth of cells without adherence to the rules that healthy normal cells obey. Carbonic anhydrase I and II (CA I and CA II) inhibitors are used for the treatment of some diseases. The available drugs in the market have limitations or side effects, which bring about the need to develop new drug candidate compound(s) to overcome the problems at issue. In this study, new pyrazole-sulphonamide hybrid compounds 4-[5-(1,3-benzodioxol-5-yl)-3-aryl-4,5-dihydro-1 H -pyrazol-1-yl]benzenesulphonamides (4a - 4j) were designed to discover new drug candidate compounds. The compounds 4a - 4j were synthesized and their chemical structures were confirmed using spectral techniques. The hypothesis tested was whether an introduction of methoxy and polymethoxy group(s) lead to an increased potency selectivity expression (PSE) value of the compound, which reflects cytotoxicity and selectivity of the compounds. The cytotoxicity of the compounds towards tumor cell lines were in the range of 6.7 - 400 µM. The compounds 4i (PSE2 = 461.5) and 4g (PSE1 = 193.2) had the highest PSE values in cytotoxicity assays. Ki values of the compounds were in the range of 59.8 ± 3.0 - 12.7 ± 1.7 nM towards hCA I and in the range of 24.1 ± 7.1 - 6.9 ± 1.5 nM towards hCA II. While the compounds 4b, 4f, 4g, and 4i showed promising cytotoxic effects, the compounds 4c and 4g had the inhibitory potency towards hCA I and hCA II, respectively. These compounds can be considered as lead compounds for further research.

Comprehensive study on potent and selective carbonic anhydrase inhibitors: Synthesis, bioactivities and molecular modelling studies of 4-(3-(2-arylidenehydrazine-1-carbonyl)-5-(thiophen-2-yl)-1H-pyrazole-1-yl) benzenesulfonamides.

In this research, rational design, synthesis, carbonic anhydrases (CAs) inhibitory effects, and cytotoxicities of the 4-(3-(2-arylidenehydrazine-1-carbonyl)-5-(thiophen-2-yl)-1H-pyrazole-1-yl)benzenesulfonamides 1-20 were reported. Compound 18 (Ki = 7.0 nM) was approximately 127 times more selective cancer-associated hCA IX inhibitor over hCA I, while compound 17 (Ki = 10.6 nM) was 47 times more selective inhibitor of hCA XI over hCA II compared to the acetazolamide. Compounds 11 (CC50 = 5.2 µM) and 20 (CC50 = 1.6 µM) showed comparative tumor-specificity (TS= > 38.5; >128.2) with doxorubicin (TS > 43.0) towards HSC-2 cancer cell line. Western blot analysis demonstrated that 11 induced slightly apoptosis whereas 20 did not induce detectable apoptosis. A preliminary analysis showed that some correlation of tumor-specificity of 1-20 with the chemical descriptors that reflect hydrophobic volume, dipole moment, lowest hydrophilic energy, and topological structure. Molecular docking simulations were applied to the synthesized ligands to elucidate the predicted binding mode and selectivity profiles towards hCA I, hCA II, and hCA IX.

Synthesis and in vitro carbonic anhydrases and acetylcholinesterase inhibitory activities of novel imidazolinone-based benzenesulfonamides.

New imidazolinone-based benzenesulfonamides 3a-e and 4a-e were synthesized in three steps and their chemical structures were confirmed by 1 H NMR (nuclear magnetic resonance), 13 C NMR, and high-resolution mass spectrometry. The benzenesulfonamides used were sulfacetamide (3a, 4a), sulfaguanidine (3b, 4b), sulfanilamide (3c, 4c), sulfadiazine (3d, 4d), sulfamerazine (3e), and sulfathiazole (4e). The compounds were evaluated against carbonic anhydrase (CA) and acetylcholinesterase (AChE) enzymes to obtain possible drug candidate/s. The lead compounds of the series were 3a and 4a against human CA (hCA) I, whereas 3d and 4a were leads against hCA II in terms of Ki values. Series 4 includes more effective CAs inhibitors than series 3 (except 3d). Series 4 compounds having a nitro group (except 4d) were 3.3-4.8 times more selective inhibitors than their corresponding analogues 3a-d in series 3, in which hydrogen was located in place of the nitro group, by considering Ki values against hCA II. Compounds 3c and 4c, where the sulfanilamide moiety is available, were the leads in terms of AChE inhibition with the lowest Ki values. The use of secondary sulfonamides was a more effective modification on CA inhibition, whereas the primary sulfonamide was the effective substitution in terms of AChE inhibitory potency.

Synthesis of benzamide derivatives with thiourea-substituted benzenesulfonamides as carbonic anhydrase inhibitors.

The novel compounds with the chemical structure of N-({4-[N'-(substituted)sulfamoyl]phenyl}carbamothioyl)benzamide (1a-g) and 4-fluoro-N-({4-[N'-(substituted)sulfamoyl]phenyl}carbamothioyl)benzamide (2a-g) were synthesized as potent and selective human carbonic anhydrase (hCA) I and hCA II candidate inhibitors. The aryl part was changed to sulfacetamide, sulfaguanidine, sulfanilamide, sulfathiazole, sulfadiazine, sulfamerazine, and sulfametazine. The Ki values of compounds 1a-g were in the range of 20.73 ± 4.32 to 59.55 ± 13.07 nM (hCA I) and 5.69 ± 0.43 to 44.81 ± 1.08 nM (hCA II), whereas the Ki values of compounds 2a-g were in the range of 13.98 ± 2.57 to 75.74 ± 13.51 nM (hCA I) and 8.15 ± 1.5 to 49.86 ± 6.18 nM (hCA II). Comparing the Ki values of the final compounds and acetazolamide, compound 1c with the sulfanilamide moiety (Ki = 5.69 ± 0.43 nM, 8.8 times) and 2f with the sulfamerazine moiety (Ki = 8.15 ± 1.5 nM, 6.2 times) demonstrated promising and selective inhibitory effects against the hCA II isoenzyme, the main target protein in glaucoma. Furthermore, compounds 1d (Ki = 20.73 ± 4.32, 4 times) and 2d (Ki = 13.98 ± 2.57, 5.9 times), which have the sulfathiazole moiety, were found as potent hCA I inhibitors. Compounds 1c and 2f can be considered as the lead compounds determined in the present study, which can be investigated further to alleviate glaucoma symptoms.

Docking Studies and Antiproliferative Activities of 6-(3-aryl-2-propenoyl)-2(3H)- benzoxazolone Derivatives as Novel Inhibitors of Phosphatidylinositol 3-Kinase (PI3Kα).

BACKGROUND: Cancer is a life-threatening group of diseases and universally, the second main cause of death. The design and development of new scaffolds targeting selective cancer cells are considered a promising goal for cancer treatment. AIMS AND OBJECTIVE: Chalcone derivatives; 6-(3-aryl-2-propenoyl)-2(3H)-benzoxazolone, were previously prepared and evaluated against the oral cavity squamous cell carcinoma cell line, HSC-2, and were reported to have remarkably high tumor selectivity. The aim of this study was to further investigate the anticancer activities of the chalcone derivatives against human colon cancer cells with a possible elucidation of their mechanism of action. METHODS: Computational studies were conducted to explore the potential interaction of the synthesized molecules with the phosphatidylinositol-4,5-bisphosphate 3-kinaseα (PI3Kα). Biological evaluation of the antiproliferative activities associated with compounds 1-23 was carried out against the colon cancer cell line, HCT116. Lactate Dehydrogenase (LDH) activity was measured to study necrosis, while the caspase-3 activation and DNA measurements were used to evaluate apoptosis in the treated cells. RESULTS: Glide studies against PI3Kα kinase domain demonstrated that the 6-(3-aryl-2-propenoyl)-2(3H)- benzoxazolone scaffold forms H-bond with K802, Y836, E849, V851, N853, Q859, and D933, and it fits the fingerprint of PI3Kα active inhibitors. Biological evaluation of the reported compounds in HCT116 cell line confirmed that the series inhibited PI3Kα activity and induced apoptosis via activation of caspase-3 and reduction of DNA content. CONCLUSION: The recently developed compounds might be employed as lead structures for the design of new antitumor drugs targeting PI3Kα.

Synthesis, structure elucidation, and in vitro pharmacological evaluation of novel polyfluoro substituted pyrazoline type sulfonamides as multi-target agents for inhibition of acetylcholinesterase and carbonic anhydrase I and II enzymes.

A novel series of 4-(3-(difluorophenyl)-5-(dimethoxyphenyl)-4,5-dihydropyrazol-1-yl)benzenesulfonamides 1-8 were designed since sulfonamide and pyrazoline pharmacophores draw great attention in novel drug design due to their wide range of bioactivities including acetylcholinesterase (AChE) and human carbonic anhydrase I and II (hCA I and hCA II) inhibitory potencies. Comprehensive structure elucidation of the compounds synthesized was carried out by 1H NMR, 13C NMR, 19F NMR, DEPT 90-135, 1H-1H COSY, 1H-13C HMQC, HMBC, and HRMS spectra. The chemical shifts and splitting patterns of the protons and carbons were affected by the fluorine atoms and exciting splitting patterns were also recorded for the fluorinated compounds. In vitro enzyme assays obviously showed that the novel compounds had a significant inhibitory profile against hCA I, hCA II and AChE enzymes at the nanomolar levels. Ki values were in the range of 3.30 ± 1.09-5.95 ± 2.26 nM for hCA I and 4.29 ± 0.91-7.14 ± 3.15 nM for hCA II, while Ki values for AChE were in the range of 3.28 ± 1.47-9.77 ± 1.86 nM. Many of thecompounds in this study can be considered as promising AChE and CA inhibitors.

Synthesis and bioactivities of 1-(4-hydroxyphenyl)-2-((heteroaryl)thio)ethanones as carbonic anhydrase I, II and acetylcholinesterase inhibitors.

The discovery of enzyme targeting inhibitors is a popular area of drug research. Biological activities of the compounds bearing phenol and heteroaryl groups make them popular groups in drug design targeting important enzymes such as acetylcholinesterase (AChE, E.C.3.1.1.7) and carbonic anhydrases (CAs, EC 4.2.1.1). 1-(4-hydroxyphenyl)- 2-((aryl)thio)ethanones as possible AChE and CAs inhibitors were synthesized, and their chemical structures were confirmed by IR, 1H NMR, 13C NMR, and HRMS. The compounds 2 and 4 were found potent AChE inhibitors with the Ki values of 22.13 ±1.96 nM and 23.71 ±2.95 nM, respectively, while the compounds 2 (Ki = 8.61 ±0.90 nM, on hCA I) and 1 (Ki = 8.76 ±0.84 nM, on hCA II) had considerable CAs inhibitory potency. The lead compounds may help the scientists for the rational designing of an innovative class of drug candidates targeting enzyme-based diseases.

Synthesis and pharmacological effects of novel benzenesulfonamides carrying benzamide moiety as carbonic anhydrase and acetylcholinesterase inhibitors.

N -(1-(4-Methoxyphenyl)-3-oxo-3-((4-( N -(substituted)sulfamoyl)phenyl)amino)prop-1-en-1-yl)benzamides 3a - g were designed since sulfonamide and benzamide pharmacophores draw great attention in novel drug design due to their wide range of bioactivities including acetylcholinesterase (AChE) and human carbonic anhydrase I and II (hCA I and hCA II) inhibitory potencies. Structure elucidation of the compounds was carried out by 1H NMR, 13C NMR, and HRMS spectra. In vitro enzyme assays showed that the compounds had significant inhibitory potential against hCA I, hCA II, and AChE enzymes at nanomolar levels. Ki values were in the range of 4.07 ± 0.38 - 29.70 ± 3.18 nM for hCA I and 10.68 ± 0.98 - 37.16 ± 7.55 nM for hCA II while Ki values for AChE were in the range of 8.91 ± 1.65 - 34.02 ± 5.90 nM. The most potent inhibitors 3g (Ki = 4.07 ± 0.38 nM, hCA I), 3c (Ki = 10.68 ± 0.98 nM, hCA II ) , and 3f (Ki = 8.91 ± 1.65 nM, AChE) can be considered as lead compounds of this study with their promising bioactivity results. Secondary sulfonamides showed promising enzyme inhibitory effects on AChE while primary sulfonamide derivative was generally effective on hCA I and hCA II isoenzymes.

Deciphering binding mechanism between bovine serum albumin and new pyrazoline compound K4.

The binding mechanism of a new and possible drug candidate pyrazoline derivative compound K4 and bovine serum albumin (BSA) was investigated in buffer solution (pH 7.4) using ultraviolet-visible light absorption and steady-state and synchronous fluorescence techniques. The fluorescence intensity of BSA was quenched in the presence of K4. The quenching process between BSA and K4 was examined at four different temperatures. Decrease of the quenching constants calculated using the Stern-Volmer equation and at increasing temperature suggested that the interaction BSA-K4 was realized through a static quenching mechanism. Synchronous fluorescence measurements suggested that K4 bounded to BSA at the tryptophan region. Fourier transform infrared spectroscopy results showed that there was no significant change in polarity around the tryptophan residue The forces responsible for the BSA-K4 interaction were examined using thermodynamic parameters. In this study, the calculated negative value of ΔG, the negative value of ΔH and the positive value of ΔS pointed to the interaction being through spontaneous and electrostatic interactions that were dominant for our cases. This study provides a very useful in vitro model to researchers by mimicking in vivo conditions to estimate interactions between a possible drug candidate or a drug and body proteins.

Novel sulphonamides incorporating triazene moieties show powerful carbonic anhydrase I and II inhibitory properties.

A series of compounds incorporating 3-(3-(2/3/4-substituted phenyl)triaz-1-en-1-yl) benzenesulfonamide moieties were synthesised and their chemical structure was confirmed by physico-chemical methods. Carbonic anhydrase (CA, EC 4.2.1.1) inhibitory effects of the compounds were evaluated against human isoforms hCA I and II. KI values of these sulphonamides were in the range of 21 ± 4-72 ± 2 nM towards hCA I and in the range of 16 ± 6-40 ± 2 nM against hCA II. The 4-fluoro substituted derivative might be considered as an interesting lead due to its effective inhibitory action against both hCA I and hCA II (KIs of 21 nM), a profile rarely seen among other sulphonamide CA inhibitors, making it of interest in systems where the activity of the two cytosolic isoforms is dysregulated.

Synthesis, cytotoxicities, and carbonic anhydrase inhibition potential of 6-(3-aryl-2-propenoyl)-2(3H)-benzoxazolones.

In this study, new chalcone compounds having the chemical structure of 6-(3-aryl-2-propenoyl)-2(3H)-benzoxazolones (1-8) were synthesised and were characterised by 1H-NMR, 13 C-NMR, and HRMS spectra. Cytotoxic and carbonic anhydrase (CA) inhibitory effects of the compounds were investigated. Cytotoxicity results pointed out that compound 4, 6-[3-(4-trifluoromethylphenyl)-2-propenoyl]-3H-benzoxazol-2-one, showed the highest cytotoxicity (CC50) and potency-selectivity expression (PSE) value, and thus can be considered as a lead compound of this study. According to the CA inhibitory results, IC50 values of the compounds 1-8 towards hCA I were in the range of 29.74-69.57 µM, while they were in the range of 18.14 - 48.46 µM towards hCA II isoenzyme. Ki values of the compounds 1-8 towards hCA I were in the range of 28.37 ± 6.63-70.58 ± 6.67 µM towards hCA I isoenzyme and they were in the range of 10.85 ± 2.14 - 37.96 ± 2.36 µM towards hCA II isoenzyme.

Synthesis, biological evaluation and in silico modelling studies of 1,3,5-trisubstituted pyrazoles carrying benzenesulfonamide as potential anticancer agents and selective cancer-associated hCA IX isoenzyme inhibitors.

Inhibition of carbonic anhydrases (CAs, EC 4.2.1.1) has clinical importance for the treatment of several diseases. They participate in crucial regulatory mechanisms for balancing intracellular and extracellular pH of the cells. Among CA isoforms, selective inhibition of hCA IX has been linked to decreasing of cell growth for both primary tumors and metastases. The discovery of novel CA inhibitors as anticancer drug candidates is a current topic in medicinal chemistry. 1,3,5-Trisubstituted pyrazoles carrying benzenesulfonamide were evaluated against physiologically abundant cytosolic hCA I and hCA II and trans-membrane, tumor-associated hCA IX isoforms by a stopped-flow CO2 hydrase method. Their in vitro cytotoxicities were screened against human oral squamous cell carcinoma (OSCC) cell lines (HSC-2) and human mesenchymal normal oral cells (HGF) via 3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide (MTT) test. Compounds 6, 8, 9, 11, and 12 showed low nanomolar hCA II inhibitory potency with Ki < 10 nM, whereas compounds 9 and 12 displayed Ki < 10 nM against hCA IX isoenzyme when compared with reference Acetazolamide (AZA). Compound 9, 4-(3-(hydrazinecarbonyl)-5-(4-nitrophenyl)-1H-pyrazol-1-yl)benzenesulfonamide, can be considered as the most selective hCA IX inhibitor over off-target cytosolic isoenzymes hCA I and hCA II with the lowest Ki value of 2.3 nM and selectivity ratios of 3217 (hCA I/hCA IX) and 3.9 (hCA II/hCA IX). Isoform selectivity profiles were also discussed using in silico modelling. Cytotoxicity results pointed out that compounds 5 (CC50 = 37.7 µM) and 11 (CC50 = 58.1 µM) can be considered as lead cytotoxic compounds since they were more cytotoxic than 5-Fluorouracil (5-FU) and Methotrexate (MTX).

Synthesis and biological evaluation of some new mono Mannich bases with piperazines as possible anticancer agents and carbonic anhydrase inhibitors.

New mono Mannich bases, (2-(4-hydroxy-3-((4-substituephenylpiperazin-1-yl)methyl)benzylidene)-2,3-dihydro-1H-inden-1-one), were prepared to evaluate their cytotoxic/anticancer properties and also their inhibitory effects on human carbonic anhydrase I and II isoenzymes (hCA I and II). Amine part was changed as [N-phenylpiperazine (1), N-benzylpiperazine (2), 1-(2-fluorophenyl)piperazine (3), 1-(4-fluorophenyl)piperazine (4), 1-(2-methoxyphenyl)piperazine (5)]. The structure of the synthesized compounds was characterized by 1H NMR, 13C NMR and HRMS spectra. Cytotoxicity results of the series pointed out that the compound 4 had the highest tumor selectivity value (TS: 59.4) possibly by inducing necrotic cell death in series. Additionally, all compounds synthesized showed a good inhibition profile towards hCA I and II isoenzymes with the Ki values between 29.6 and 58.4 nM and 38.1-69.7 nM, respectively. These values were lower than the reference compound AZA. However, it seems that the compounds 4 and 2 can be considered as lead compounds of CA studies with the lowest Ki values in series for further designs.

New phenolic Mannich bases with piperazines and their bioactivities.

In this study, new Mannich bases, 2-(4-hydroxy-3-methoxy-5-((substitutedpiperazin-1-yl)methyl)benzylidene)-2,3-dihydro-1H-inden-1-one (1, 2, 4, 5, 8), 2-(3-((substituted)piperazin-1-yl)methyl)-4-hydroxy-5-methoxybenzylidene)-2,3-dihydro-1H-inden-1-one (3, 6, 7) were synthesized with the reaction of vanilin derived chalcone compound (2-(4-hydroxy-3-methoxybenzylidene)indan-1-one), paraformaldehyde and suitable amine in 1:1.2:1 mol ratios. Amine part was changed as N-methylpiperazine (1), N-phenylpiperazine (2), N-benzylpiperazine (3), 1-(2-methoxyphenyl)piperazine (4), 1-(3-methoxyphenyl)piperazine (5), 1-(2-fluorophenyl)piperazine (6), 1-(4-fluorophenyl)piperazine (7), and 1-(3-trifluoromethyl)phenyl piperazine (8). Compounds were evaluated in terms of cytotoxic/anticancer and CA inhibitory effects. According to the results obtained, the compounds 2 and 8 had the highest potency selectivity expression (PSE) values (60.6 and 19.2, respectively). On the other hand, the compounds 3 (Ki = 209.6 ±â€¯70.2 pM) and 5 (Ki = 342.66 ±â€¯63.72 pM) had the lowest Ki values in CA inhibition experiments towards hCA I and hCA II, respectively. In conclusion, the compounds 2 (with cytotoxic/anticancer activity), 3 (with hCA I inhibiting activity) and 5 (with hCA II inhibiting activity) can be leading compounds of the study for further designs and evaluations.

Investigation of inhibitory properties of some hydrazone compounds on hCA I, hCA II and AChE enzymes.

Recently, inhibition of carbonic anhydrase (hCA) and acetylcholinesterase (AChE) have appeared as a promising approach for pharmacological intervention in a variety of disorders such as glaucoma, epilepsy, obesity, cancer, and Alzheimer's disease. Keeping this in mind, N,N'-bis[(1-aryl-3-heteroaryl)propylidene]hydrazine dihydrochlorides, N1-N11, P1, P4-P8, and R1-R6, were synthesized to investigate their inhibitory activity against hCA I, hCA II, and AChE enzymes. All compounds in N, P, and R-series inhibited hCAs (I and II) and AChE more efficiently than the reference compounds acetazolamide (AZA), and tacrine. According to the activity results, the most effective inhibitory compounds were in R-series with the Ki values of 203 ±â€¯55-473 ±â€¯67 nM and 200 ±â€¯34-419 ±â€¯94 nM on hCA I, and hCA II, respectively. N,N'-Bis[1-(4-fluorophenyl)-3-(morpholine-4-yl)propylidene]hydrazine dihydrochlorides, N8, in N-series, N,N'-Bis[1-(4-hydroxyphenyl)-3-(piperidine-1-yl)propylidene]hydrazine dihydrochlorides, P4, in P-series, and N,N'-bis[1-(4-chlorophenyl)-3-(pyrrolidine-1-yl)propylidene]hydrazine dihydrochlorides, R5, in R-series were the most powerful compounds against hCA I with the Ki values of 438 ±â€¯65 nM, 344 ±â€¯64 nM, and 203 ±â€¯55 nM, respectively. Similarly, N8, P4, and R5 efficiently inhibited hCA II isoenzyme with the Ki values of 405 ±â€¯60 nM, 327 ±â€¯80 nM, and 200 ±â€¯34 nM, respectively. On the other hand, P-series compounds had notable inhibitory effect against AChE than the reference compound tacrine and the Ki values were between 66 ±â€¯20 nM and 128 ±â€¯36 nM. N,N'-Bis[1-(4-fluorophenyl)-3-(piperidine-1-yl)propylidene]hydrazine dihydrochlorides, P7, was the most potent compound on AChE with the Ki value of 66 ±â€¯20 nM. The other most promising compounds, N,N'-bis[1-(4-hydroxyphenyl)-3-(morpholine-4-yl)propylidene]hydrazine dihydrochlorides, N4 in N-series and N,N'-bis[1-(4-hydroxyphenyl)-3-(pyrrolidine-1-yl)propylidene]hydrazine dihydrochlorides, R4 in R-series were againts AChE with the Ki values of 119 ±â€¯20 nM, 88 ±â€¯14 nM, respectively.