Synthesis and Screening of Human Monoamine Oxidase-A Inhibitor Effect of New 2-Pyrazoline and Hydrazone Derivatives.

A group of 3,5-diaryl-2-pyrazoline and hydrazone derivatives was prepared via the reaction of various chalcones with hydrazide compounds in ethanol. Twenty original compounds were synthesized. Ten of these original compounds have a pyrazoline structure, nine of these original compounds have a hydrazone structure, and one of these original compounds has a chalcone structure. Structural elucidation of the compounds was performed by IR, (1)H NMR, (13)C NMR, mass spectral data, and elemental analyses. These compounds were tested for their inhibitory activities toward the A and B isoforms of human monoamine oxidase (MAO). Except for 3k and 6c, all compounds were found to be competitive, reversible, and selective inhibitors for either one of the isoforms (hMAO-A or MAO-B). Compounds 3k and 6c were found to be competitive, reversible, but non-selective MAO inhibitors. Compound 6h showed hMAO-B inhibitory activity whereas the others potently inhibited hMAO-A. Compound 5c showed higher selectivity than the standard drug moclobemide. According to the experimental K(i) values, compounds 6i, 6d, and 6a exhibited the highest inhibitory activity toward hMAO-A. The AutoDock 4.2 program was employed to perform automated molecular docking. The calculated results obtained computationally were in good agreement with the experimental values.

Synthesis of some novel hydrazone and 2-pyrazoline derivatives: monoamine oxidase inhibitory activities and docking studies.

A novel series of 2-pyrazoline and hydrazone derivatives were synthesized and investigated for their human monoamine oxidase (hMAO) inhibitory activity. All compounds inhibited the hMAO isoforms (MAO-A or MAO-B) competitively and reversibly. With the exception of 5i, which was a selective MAO-B inhibitor, all derivatives inhibited hMAO-A potently and selectively. According to the experimental Ki values, compounds 6e and 6h exhibited the highest inhibitory activity towards the hMAO-A, whereas compound 5j, which carries a bromine atom at R(4) of the A ring of the pyrazoline, appeared to be the most selective MAO-A inhibitor. Tested compounds were docked computationally into the active site of the hMAO-A and hMAO-B isozymes. The computationally obtained results were in good agreement with the corresponding experimental values.

Studies on the antioxidant activity of some thiazolidinedione, imidazolidinedione and rhodanine derivatives having a flavone core.

A series of flavonyl-2,4-thiazolidinedione, imidazolidinedione and rhodanine derivatives were tested for their antioxidant activity as scavengers of oxygen free radicals. Free radical scavenging activities, including superoxide anion radical O2•, hydroxyl radical (HO(•)) and 2,2'-diphenyl-1-picrylhydrazyl free radical have been evaluated using chemiluminescence, electron paramagnetic resonance and spin trapping with 5,5-dimethyl-1-pyrroline-1-oxide as a spin trap. Potassium superoxide in dimethylsulfoxide and 18-crown-6 ether were used for the production of O2•. Hydroxyl radical was generated using the Fenton reaction. Ten of the eleven examined compounds exhibited decrease in chemiluminescence, but there were large differences in the decrease, ranging from 16% to 89%; also, two of these compounds increased light emission by about 200%. On the contrary, all compounds tested exhibited 30-68% scavenging HO(•) and 25-96% scavenging the DPPH(•) radical respectively. Possible mechanisms are proposed to explain the results.

Studies on the antioxidant activities of some new chromone compounds.

Recent reviews evidence that the naturally occurring compounds containing the chromone skeleton exhibit antiradical activities, providing protection against oxidative stress. The antioxidant activities of 13 new synthesized chromonyl-2,4-thiazolidinediones, chromonyl-2,4-imidazolidinediones and chromonyl-2-thioxoimidzolidine-4-ones were evaluated using in vitro antioxidant assays, including superoxide anion radical (O2(-•)), hydroxyl radical (HO(•)), 2,2-diphenyl-1-picryl-hydrazyl free radical (DPPH(•)) scavenging capacity and total antioxidant capacity ferric ion reducing activity. Superoxide anion radical was produced using potassium superoxide/18-crown-6-ether dissolved in dimethylsulfoxide, and the Fenton-like reaction (Fe(II) + H2O2) was a generator of hydroxyl radicals. Chemiluminescence, spectrophotometry, electron paramagnetic resonance (EPR) and 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) as the spin trap were the measurement techniques. The results showed that the majority of the chromone derivatives tested showed a strong scavenging effect towards free radicals, similar to the chemiluminescence reaction with superoxide anion radical with a high activity, inhibition of the DMPO-OOH radical EPR signal (24-58%), the DMPO-OH radical EPR signal (4-75%) and DPPH radical EPR signal (6-100%) at 1 mmol/L. Several of the examined compounds exhibited the high reduction potentials. The results obtained show that the new synthesized chromone derivatives may directly scavenger reactive oxygen species and thus may play a protective role against oxidative damage.

Synthesis and antidiabetic activity of 2,4-thiazolidindione, imidazolidinedione and 2-thioxo-imidazolidine-4-one derivatives bearing 6-methyl chromonyl pharmacophore.

Numerous compounds have been prepared in order to improve the pharmacological profile of insulinotropic activities. In the present paper, we report the synthesis and the in vitro insulin releasing activity of the 6-methyl-chromonyl-2,4-thiazolidinediones (IIIa-c, IVa-c, Va-c). Compounds IIIb, IIIc, IVa-c, Va and Vc (at lower concentration; 0.001 mg/mL) were able to increase insulin release in the presence of 5.6 mmol/L glucose. In this series, the most potent compound is IVa having methyl group at N3 position of TZD ring.

Free radical scavenging abilities of flavonyl-thiazolidine-2,4-dione compounds.

Free radical scavenging activity of flavonyl-thiazolidine-2,4-dione compounds has been evaluated using chemiluminescence, electron spin resonance spectroscopy with 5,5-dimethyl-1-pyrroline-1-oxide as spin trap and DPPH (2,2'-diphenyl-1-picrylhydrazyl) method. The examined compounds exhibited 28-50% scavenging superoxide anion radical O2⁻ⁱ16.7-76.7% hydroxyl radical (HO•) and 9-40% DPPH radical. Compounds containing carbonyl group in their structure can be considered as antioxidants with high relevance and great biological importance.

Synthesis and antidiabetic activity of some new chromonyl-2,4-thiazolidinediones.

A series of chromonyl-2,4-thiazolidinediones/imidazolidinediones/2-thioxo-imidazolidine-4-ones (IIIa-i, IVa-i) was prepared by Knoevenagel reaction of 2,4-thiazolidinedione/2,4-imidazolidinedione/2-thioxo-imidazolidine-4-one (IIa-c) with 2/3-formyl chromone (Ia-b) and then alkylation with methyl/ethyl iodide. The prepared compounds were tested for their insulinotropic activities in INS-1 cells. Compounds iVb and iVc (at lower concentration, 1 µg/mL) were able to increase insulin release in the presence of 5.6 mmol/L glucose." should be written as "Compounds IVb and IVc (at lower concentration, 1 µg/mL) and also IIId and IIIg (at higher concentration) were able to increase insulin release in the presence of 5.6 mmol/L glucose. Compounds iVb and iVc (at lower concentration, 1 µg/mL) were able to increase insulin release in the presence of 5.6 mmol/L glucose.

Hydroxyl and superoxide radical scavenging abilities of chromonyl-thiazolidine-2,4-dione compounds.

The oxygen free radical scavenging activities of 15 chromonyl-thiazolidine-2,4-dione compounds (CTDs) were examined in chemical systems producing superoxide anion radicals, O2(-*) (potassium superoxide-18-crown-6 ether-DMSO), and hydroxyl radicals, HO(*) (a Fenton reaction: Fe(II)-H2O2-sodium trifluoroacetate, pH 6.15). Chemiluminescence and electron spin resonance (ESR) spectroscopy using 5,5-dimethyl-1-pyrroline-1-oxide (DMPO) as spin trap were applied to evaluate antioxidant behaviour of CTDs towards the oxygen radicals. The results indicated that 11 of the 15 tested compounds showed a significant inhibitory effect on the chemiluminescence generated from the O2(-*)-generating system, ranging from 41 to 86%, and 13 CTDs quenched the ESR signal of the DMPO-OH spin adduct by 33-86%, at a concentration of 1 mmol L(-1). Our findings demonstrate that CTDs could be good free radical scavengers.

Scavenging capacities of some thiazolyl thiazolidine-2,4-dione compounds on superoxide radical, hydroxyl radical, and DPPH radical.

The scavenging effects of eighteen thiazolyl thiazolidine-2,4-dione compounds (TTCs) on superoxide radical ( (-) (*) ) (2), hydroxyl radical HO(*), and 1,1-diphenyl-2-picrylhydrazyl (DPPH(*)) radical were evaluated by the chemiluminescence technique, electron spin resonance spectrometry (ESR) and visible spectrophotometry, respectively. The examined compounds were shown to have 27-59% ( (-) (*) ) (2) scavenging ability, 19-69% HO(*) scavenging activity and 2-32% DPPH(*) scavenging ability. This property of the tested compound seems to be important in the prevention of various diseases of free radicals etiology.

Synthesis and biological activity of some new flavonyl-2,4-thiazolidinediones.

A new series of flavonyl-2,4-thiazolidinediones (Va-c, VIa-c) was prepared by Knoevenagel reaction. The synthesized compounds were tested for their ability to inhibit rat kidney aldose reductase (AR) and for their insulinotropic activities in INS-1 cells. Compound Vb was able to increase insulin release in the presence of 5.6mmol/l glucose. Compounds VIa-c displayed moderate to high AR inhibitory activity levels. Particularly, compound VIa showed the highest AR inhibitory activity (86.57%).

Synthesis and aldose reductase inhibitory activity of some new chromonyl-2,4-thiazolidinediones.

As it is known that still, there were no any confident ARIs on the market and they have several side effects, we need to approve new ARIs to reduce diabetic complications especially which have effect on the cataract formation. In this study, a new series of chromonyl-2,4-thiazolidinediones (Ia-e, IIa-e, IIIa-e) were prepared by Knoevenagel reaction with substituted 3-formylchromones (3a-e) and unsubstituted (1) or substituted 2,4-thiazolidinedione (2). The synthesized compounds were tested for their ability to inhibit rat kidney AR by an in vitro spectrophotometric assay. Compound IIIe showed the highest inhibitory activity (82.43+/-0.76%). Compounds Ia-e and IIIa-d also showed significant inhibitory activity (42.40+/-5.78, 52.71+/-3.31, 49.69+/-1.55, 50.80+/-3.62, 46.70+/-2.33, 49.44+/-4.53, 61.17+/-4.74, 68.58+/-2.05, 77.28+/-0.26%, respectively).

In vitro aldose reductase inhibitory activity of some flavonyl-2,4-thiazolidinediones.

Aldose reductase (AR) is implicated to play a critical role in diabetes and cardiovascular complications because of the reaction it catalyzes. AR enzyme appears to be the key factor in the reduction of glucose to sorbitol. Synthesis and accumulation of sorbitol in cells due to AR activity is the main cause of diabetic complications, such as diabetic cataract, retinopathy, neuropathy and nephropathy. Aldose reductase inhibitors have been found to prevent sorbitol accumulation in tissues. Numerous compounds have been prepared in order to improve the pharmacological prophile of inhibition of aldose reductase enzyme. In this study, seventeen flavonyl-2,4-thiazolidinediones (flavonyl-2,4-TZD) (Ia-e, IIa-e and IIIa-g) were tested for their ability to inhibit rat kidney AR. Compound Ib showed the highest inhibitory activity (88.69 +/- 1.46%) whereas Ia, IIa, IIIa, IIIb also showed significant inhibitory activity (49.26 +/- 2.85, 67.29 +/- 1.09, 71.11 +/- 1.95, 64.86 +/- 1.21%, respectively).

Antioxidant properties of flavone-6(4')-carboxaldehyde oxime ether derivatives.

The in vitro antioxidant properties of some flavone-6(4)-carboxaldehyde oxime ether derivatives (Ia-f, IIa-f) were determined by their effects on the rat liver microsomal NADPH-dependent lipid peroxidation (LP) levels by measuring the formation of 2-thiobarbituric acid reactive substances. The free radical scavenging properties of the compounds were also examined in vitro by determining their capacity to scavenge superoxide anions and interact with the stable free radical 2, 2-diphenyl-1-picrylhydrazyl (DPPH). The most active compounds, IIb (Flavone-4'-carboxaldehyde-O-ethyl oxime) and Id (Flavone-6-carboxaldehyde-O-[2-(1-pyrolidino) ethyl] oxime), caused 98 and 79% inhibition of superoxide anion production and DPPH stable free radical at 10(-3) M, respectively.

Synthesis and hypoglycemic activity of some substituted flavonyl thiazolidinedione derivatives--fifth communication: flavonyl benzyl substituted 2,4-thiazolidinediones.

A new series of 3-benzyl(p-substituted benzyl)-5-[3'-(4H-4-oxo-1-benzopyran-2-yl)-benzylidene]-2,4-thiazolidinediones (8a-e) were synthesized. These products were prepared by Knoevenagel reaction from 3'-flavone carboxaldehyde and 3-substituted 2,4-thiazolidinediones. In vitro insulinotropic activity was determined for compounds 6a-e, 7a-e, 8b and 8c.

Synthesis and antimicrobial activity of some novel thiazolidine-2,4-dione derivatives.

In this study, a series of phenylethylsulfanyl-1,3-thiazolo-thiazolidine-2,4-dione derivatives (VII a-f, VIII a-f) and 5-methyl-[1,2,4]triazolyl-sulfanyl-1,3-thiazolo-thiazolidine-2,4-dione derivatives (IX a-f, X a-f) were synthesized and evaluated for their antibacterial and antifungal activities against S. aureus (ATCC 25923), methicillin resistant S. aureus (MRSA ATCC 43300), B. subtilis (ATCC 6633), E. coli (ATCC 23556) and C. albicans (ATCC10145). All the compounds were found active against used bacteria.

Synthesis and antimicrobial activity of some new thiazolyl thiazolidine-2,4-dione derivatives.

In this study, a series of thiazolyl thiazolidine-2,4-dione derivatives (Va-f and VIa-f) were synthesized and evaluated for their antibacterial and antifungal activities against Staphylococcus aureus (ATCC 25923), methicillin resistant S. aureus (MRSA ATCC 43300), methicillin resistant S. aureus (MRSA isolate), and Escherichia coli (ATCC 23556) and C. albicans (ATCC10145). All the compounds were found active against used microorganisms.

Synthesis and antidiabetic activity of some new chromonyl-2,4-thiazolidinediones.

A series of chromonyl-2,4-thiazolidinediones (VIa-f) and chromonyl-2,4-imidazolidinediones (VIIa-f) was prepared by Knoevenagel reaction of substituted benzyl-2,4-thiazolidinediones (IVa-f) and substituted benzyl-2,4-imidazolidinediones (Va-f) with chromone-3-carboxaldehyde (I). The prepared compounds were tested for their insulinotropic activities in INS-1 cells. Compounds VIa, VIb, VId and VIIe (at lower concentration; 1 microg/ml) were able to increase insulin release in the presence of 5.6 mmol/l glucose; their effects were lower than that of glibenclamide (CAS 10238-21-8). The activity of the most potent compound (VId) was still 9% less than that of glibenclamide.

Synthesis and antidiabetic activity of novel 2,4-thiazolidinedione derivatives containing a thiazole ring.

A series of thiazolyl-2,4-thiazolidinediones (Ia-f, IIa-f and IIIa-f) was prepared by Knoevenagel reaction of substituted benzyl-2,4-thiazolidinediones (4a-f) with chlorothiazolecarbaldehydes (2, 3a-b). The prepared compounds were tested for their insulinotropic activities in INS-1 cells. A significant insulinotropic effect was seen with compounds If and IIa.

Antibacterial 4-amino-N-(5-methylisoxazol-3-yl)-N-[(4-oxo-2-phenyl-4H-1-benzopyran-6-yl)methyl]benzenesulfonamide.

In the molecule of the title compound, C26H21N3O5S, a new type of sulfonamide derivative with potential antibacterial activity, the flavone moiety is almost planar. The isoxazole and aminophenyl rings are also planar and make dihedral angles of 77.0 (2) and 81.4 (1) degrees , respectively, with the best plane of the flavone ring system. The crystal structure is stabilized by intra- and intermolecular hydrogen bonds.

Synthesis and biological activity of some new flavone derivatives.

In this study, a new series of 2-(4-[substituted benzylamino-methyl)-phenyl]-4H-benzopyrane-4-one (IVa-e) and N-substituted benzyl-N-[4-(4-oxo-4H-benzopyrane-2-yl)benzyl]-3-phenyl-acrylamide (Va-e) derivatives was synthesized and the results of their biological activity are reported. The synthesized compounds were tested for their in vitro antifungal and antibacterial activities. Compound IVa showed the best antifungal activity compared with miconazole (CAS 22916-47-8). Compound IVe indicated the same antibacterial activity compared with the control drug ampicillin (CAS 69-53-4).