Mohamed I. Attia

Synthesis and anticancer potential of certain novel 2-oxo-N'-(2-oxoindolin-3-ylidene)-2H-chromene-3-carbohydrazides

Treatment of ethyl 3-hydrazinyl-3-oxopropanoate (6) with indoline-2,3-dione derivatives 7a-g gave ethyl 3-oxo-3-(2-(2-oxoindolin-3-ylidene)hydrazinyl)propanoates 8a-g which were allowed to react with the appropriate salicyaldehyde 9a and/or 9b to furnish the chromene-based hydrazones 10a-i. Compounds 10a-i displayed a significant activity against HT-29 colon cancer cell line and a moderate activity against leukemia K562 cell line. Compound 10f emerged as the most active congener toward HT-29 colon cancer cell line with IC₅₀ = 7.98 ± 0.05 μM whereas compound 10c exhibited the best antiproliferative activity against leukemia K562 cell line with IC₅₀ = 9.44 ± 0.02 μM. Moreover, compound 1e showed 87.81 ± 7% inhibition of side population (SP) HT-29 colon cancer stem cells.

N‐Acetyl‐5‐arylalkoxytryptamine Analogs: Probing the Melatonin Receptors for MT1‐Selectivity

A series of melatonin analogs obtained by the replacement of the ether methyl group with larger arylalkyl and aryloxyalkyl substituents was prepared in order to probe the melatonin receptors for MT1‐selectivity. The most MT1‐selective agents 11 and 15 were substituted with a Ph(CH2)3 or a PhO(CH2)3 group. Compounds 11 and 15 displayed 11.5‐fold and 11‐fold higher affinity for the MT1 receptors than for the MT2 subtype. Interestingly, in our binding assay 11 and 15 have shown considerably higher MT1‐affinity and selectivity than the reference ligand, the dimeric agomelatine 1a.

FT-IR, FT-Raman, molecular structure, first order hyperpolarizability, HOMO and LUMO analysis, MEP and NBO analysis of 3-(adamantan-1-yl)-4-(prop-2-en-1-yl)-1H-1,2,4-triazole-5(4H)-thione, a potential bioactive agent

The optimized molecular structure, vibrational frequencies, corresponding vibrational assignments of 3-(adamantan-1-yl)-4-(prop-2-en-1-yl)-1H-1,2,4-triazole-5(4H)-thione have been investigated experimentally and theoretically using Gaussian09 software package. Potential energy distribution of normal modes vibrations was done using GAR2PED program. The HOMO and LUMO analysis are used to determine the charge transfer within the molecule. The stability of the molecule arising from hyperconjugative interaction and charge delocalization has been analyzed using NBO analysis. The calculated geometrical parameters are in agreement with the XRD data. The calculated first hyperpolarizability is high and the title compound is an attractive candidate for further studies in nonlinear optical applications. To estimate the chemical reactivity of the molecule, the molecular electrostatic potential is calculated for the optimized geometry of the molecule.

Synthesis and Anti‐Candida Potential of Certain Novel 1‐[(3‐Substituted‐3‐phenyl)propyl]‐1H‐imidazoles

The synthesis and anti‐Candida activity of 1‐[(3‐aroyloxy‐3‐phenyl)propyl]‐1H‐imidazoles 5a–f and 1‐[(3‐alkyl/aralkyl/phenyl‐3‐phenyl)propan‐3‐ol]‐1H‐imidazoles 5g–j are reported. The influence of the ester formation and different substitutions on the anti‐Candida activity of the alcohol 4 was investigated. Among the newly developed bioactive chemical entities, compounds 5b and 5c displayed minimum inhibitory concentrations (MICs) against Candida albicans and Candida pseudotropicales comparable to that of tioconazole and more potent than miconazole.

Synthesis and pharmacological evaluation of 1,2,3,4-tetrahydropyrazino[1,2-a]indole and 2-[(phenylmethylamino)methyl]-1H-indole analogues as novel melatoninergic ligands.

Two novel series of melatonin-derived compounds have been synthesized and pharmacologically evaluated at the MT(1) and MT(2) subtypes of melatonin receptors. Compounds 12b-c are non-selective high-affinity MT(1) and MT(2) receptor ligands (K(i)=7-11 nM). Compound 12b had little intrinsic activity at the MT(1) receptor and no intrinsic activity at the MT(2) receptor. Compound 20d displayed the highest MT(2) binding affinity (K(i)=2 nM) and moderate selectivity toward the MT(2) subtype (K(i) MT(1)/MT(2) ratio=8) behaving as MT(2) antagonist and MT(1) agonist (IC(50)=112 pM). The findings help define SARs around the positions 1 and 2 of melatonin with respect to binding affinity, MT(2) selectivity, and intrinsic activity.

Synthesis and pharmacological evaluation of pentacyclic 6a,7-dihydrodiindole and 2,3-dihydrodiindole derivatives as novel melatoninergic ligands

The synthesis of novel melatonin analogues 3a and 4a-c designed as melatonin receptor ligands is described. Among the newly synthesized ligands, 2-((S)-2-hydroxymethylindolin-1-ylmethyl)-melatonin 4b displayed the highest affinity for MT(1) receptors (K(i)=9.8 nM) and for MT(2) subtype (K(i)=7.8 nM), whereas the rigid pentacyclic ligand 3 showed the highest selectivity towards the MT(2) receptor subtype (K(i)=319.3 nM for MT(1) and K(i)=65.2 nM for MT(2)).

In Vitro Anti-Candida Activity of Certain New 3-(1H-Imidazol-1-yl)propan-1-one Oxime Esters

Anti-Candida activities of certain new oximes 4a–d and their respective aromatic esters 5a–l are reported. The tested compounds 4a–d and 5a–l exhibited better anti-Candida profiles than fluconazole. Compound 5j, namely (E)-3-(1H-imidazol-1-yl)-1-phenylpropan-1-one O-4-chlorobenzoyl oxime emerged as the most active congener, with a MIC value of 0.0054 µmol/mL being more potent than both fluconazole (MIC > 1.6325 µmol/mL) and miconazole (MIC value = 0.0188 µmol/mL) as a new anti-Candida albicans agent.

Schiff bases of indoline-2,3-dione (isatin) with potential antiproliferative activity

BackgroundCancer is one of the most dreaded diseases and it is a leading cause of mankind death worldwide. Recent reports documented a remarkable antiproliferative activity of isatin nucleus against various cancer cell lines. The current work describes the antiproliferative activity of Schiff bases of combinatorial mixtures of the isatin derivatives M1-M22 as well as the individual compounds 1-11(A-K) of these combinatorial mixtures.ResultsThe designed combinatorial library composed from eleven hydrazides A-K and eleven isatin derivatives 1-11 has been synthesized to formally generate 22 mixtures, M1-M22 of 121 Schiff bases, and their antiproliferative activity against K562 chronic myelogenous leukemia cells was evaluated. The indexed method of analysis of the prepared library was applied to elucidate the active components in the tested mixtures M1-M22. The predictions from the crossing procedure was validated through evaluation of the antiproliferative activity of individual compounds 1-11(A-K) of the library. Individual compounds 1-11(A-K) were also evaluated against the non-tumorigenic MCF-12A cell line to investigate their selectivity. A pharmacophore model was developed to further optimize the antiproliferative activity among this series of compounds.ConclusionsVariable antiproliferative activity was revealed with the investigated mixtures M1-M22 and the individual compounds 1-11(A-K). Most of the tested mixtures and several individual Schiff bases displayed high potency with IC50 values in the low micromolar range. A considerable selectivity of some individual compounds to the tumorigenic K562 cell line compared with the non-tumorigenic MCF-12A cell line was observed as indicated by their selectivity index (SI).

New hydrazonoindolin-2-ones: Synthesis, exploration of the possible anti-proliferative mechanism of action and encapsulation into PLGA microspheres

The synthesis and molecular characterization of new isatin-based hydrazonoindolin-2-ones 4a-o and 7a-e are reported. The in vitro anti-proliferative potential of the synthesized compounds 4a-o and 7a-e was examined against HT-29 (colon), ZR-75 (breast) and A549 (lung) human cancer cell lines. Compounds 7b, 7d and 7e were the most active congeners against the tested human cancer cell lines with average IC50 values of 4.77, 3.39 and 2.37 μM, respectively, as compared with the reference isatin-based drug, sunitinib, which exhibited an average IC50 value of 8.11 μM. Compound 7e was selected for further pharmacological evaluation in order to gain insight into its possible mechanism of action. It increased caspase 3/7 activity by 2.4- and 1.85-fold between 4 and 8 h of treatment, respectively, at 10 μM and it caused a decrease in the percentage of cells in the G1 phase of the cell cycle with a corresponding increase in the S-phase. In addition, compound 7e increased phosphorylated tyrosine (p-Tyr) levels nearly two-fold with an apparent IC50 value of 3.8 μM. The 7e-loaded PLGA microspheres were prepared using a modified emulsion-solvent diffusion method. The average encapsulation efficiency of the 7e-loaded PLGA microspheres was 85% ± 1.3. While, the in vitro release profile of the 7e-loaded microspheres was characterized by slow and continuous release of compound 7e during 21 days and the release curve was fitted to zero order kinetics. Incorporation of 7e into PLGA microspheres improved its in vitro anti-proliferative activity toward the human cancer cell line A549 after 120 h incubation period with an IC50 value less than 0.8 μM.

2-[(1,3-Dihydro-2H-isoindol-2-yl)methyl]melatonin – a novel MT2-selective melatonin receptor antagonist

A synthesis and pharmacological evaluation of new melatonin receptor ligands obtained by 2-substitution of melatonin with (indol-1-yl)methyl, (isoindolin-2-yl)methyl, and (tetrahydroiso-quinolin-2-yl)methyl groups is reported. The isoindoline analogue a displays high MT2 binding affinity (Ki = 2 nM) and high selectivity towards the MT2 subtype (Ki MT1/Ki MT2 = 124) behaving as an MT2-antagonist.