Omar M. Aly

Synthesis and investigation of anti-inflammatory activity and gastric ulcerogenicity of novel nitric oxide-donating pyrazoline derivatives

A group of 3,5-diaryl-2-pyrazoline derivatives were prepared via the reaction of various chalcones with hydrazine hydrate in ethanol. A group of NO-donating-2-pyrazoline derivatives were synthesized by carrying a nitrate ester group or an oxime group onto the prepared pyrazoline derivatives through different spacers. The prepared compounds were evaluated for their anti-inflammatory activity using carrageenan-induced rat paw edema and compared to a well-known NSAID, indomethacin as a reference drug. The ability of the prepared compounds to induce gastric toxicity was also evaluated. Most of the prepared compounds showed significant anti-inflammatory activity at the injected dose (100mg/kg) but they were safer than indomethacin in regard to gastric toxicity. The incorporation of the NO-donating group into the parent pyrazoline derivatives caused a non-significant reduction in the anti-inflammatory activity while a marked decrease in gastric ulcerations induced by their parent pyrazolines was observed.

Design, synthesis and hypolipidemic activity of novel 2-(naphthalen-2-yloxy)propionic acid derivatives as desmethyl fibrate analogs.

A series of 2-(naphthalen-2-yloxy)propionic acid derivatives were prepared. The hypolipidemic activity of the new compounds as well as the intermediate acid 2 was evaluated in the high cholesterol diet (HCD) fed hyperlipidemic rat model. Interestingly, the S-alkylated mercaptotriazole 8b and the 1,3,4-oxadiazole 9 produced striking reduction of serum levels of total cholesterol (TC), triglycerides (TGs) and low-density lipoproteins (LDLs) and elevation of serum high-density lipoproteins (HDLs) being more active than the reference gemfibrozil. In addition, the 1,2,4-triazole 7a, the hydroxypyrazoline 10 and the pyrazolone derivative 11 exhibited good hypolipidemic activity on different lipid parameters.

Synthesis, Cytotoxic Properties and Tubulin Polymerization Inhibitory Activity of Novel 2-Pyrazoline Derivatives

A series of novel 1‐(3′,4′,5′‐trimethoxybenzoyl)‐3,5‐diarylpyrazoline derivatives were synthesized and evaluated for their cytotoxic properties on different cancer cell lines and tubulin polymerization inhibitory activity. Compounds 6d and 6e exhibited remarkable cytotoxic activity against different cancer cell lines with good tubulin polymerization inhibitory activity. Compound 6d exhibited moderate selectivity toward renal cancer and breast cancer subpanels with selectivity ratios of 3.06 and 5.11, respectively, at the cytostatic activity (TGI) level. Compounds 6e and 6d achieved good tubulin polymerization inhibitory activity with IC50 values of 17 and 40 µM, respectively. The photomicrographs made for compounds 6d and 6e on cellular microtubules indicated that the cytotoxicity of these compounds can be attributed to their ability to interfere with microtubule assembly. Molecular modeling studies involving compound 6e with the colchicine binding site of α,β‐tubulin revealed hydrogen‐bonding and hydrophobic interactions with several amino acids in the colchicine binding site of β‐tubulin.

Direct and nitroxyl (HNO)-mediated reactions of acyloxy nitroso compounds with the thiol-containing proteins glyceraldehyde 3-phosphate dehydrogenase and alkyl hydroperoxide reductase subunit C.

Nitroxyl (HNO) reacts with thiols, and this reactivity requires the use of donors with 1-nitrosocyclohexyl acetate, pivalate, and trifluoroacetate, forming a new group. These acyloxy nitroso compounds inhibit glyceraldehyde 3-phosphate dehydrogenase (GAPDH) by forming a reduction reversible active site disulfide and a reduction irreversible sulfinic acid or sulfinamide modification at Cys244. Addition of these acyloxy nitroso compounds to AhpC C165S yields a sulfinic acid and sulfinamide modification. A potential mechanism for these transformations includes nucleophilic addition of the protein thiol to a nitroso compound to yield an N-hydroxysulfenamide, which reacts with thiol to give disulfide or rearranges to sulfinamides. Known HNO donors produce the unsubstituted protein sulfinamide as the major product, while the acetate and pivalate give substituted sulfinamides that hydrolyze to sulfinic acids. These results suggest that nitroso compounds form a general class of thiol-modifying compounds, allowing their further exploration.

Nitroxyl (HNO): A Reduced Form of Nitric Oxide with Distinct Chemical, Pharmacological, and Therapeutic Properties

Nitroxyl (HNO), the one-electron reduced form of nitric oxide (NO), shows a distinct chemical and biological profile from that of NO. HNO is currently being viewed as a vasodilator and positive inotropic agent that can be used as a potential treatment for heart failure. The ability of HNO to react with thiols and thiol containing proteins is largely used to explain the possible biological actions of HNO. Herein, we summarize different aspects related to HNO including HNO donors, chemistry, biology, and methods used for its detection.

Synthesis, cytotoxic activity, and tubulin polymerization inhibitory activity of new pyrrol-2(3H)-ones and pyridazin-3(2H)-ones.

A series of new pyrrol-2(3H)-ones 4a-f and pyridazin-3(2H)-ones 7a-f were synthesized and characterized using different spectroscopic tools. Some of the tested compounds revealed moderate activity against 60 cell lines. The E form of the pyrrolones 4 showed good cytotoxic activity than both the Z form and the corresponding open amide form. Furthermore, the in vitro cytotoxic activity against HepG2 and MCF-7 cell lines revealed that compounds (E)4b, 6f and 7f showed good cytotoxic activity against HepG2 with IC50 values of 11.47, 7.11 and 14.80μM, respectively. Compounds (E)4b, 6f, 7d and 7f showed a pronounced inhibitory effect against cellular localization of tubulin. Flow cytometric analysis indicated that HepG2 cells treated with (E)4b showed a predominated growth arrest at the S-phase compared to that of G2/M-phase. Molecular modeling study using MOE® program indicated that most of the target compounds showed good binding of β-subunit of tubulin with the binding free energy (dG) values about -10kcal/mole.

1,3,4-oxadiazole-2-thione Derivatives; Novel Approach for Anticancer and Tubulin Polymerization Inhibitory Activities

A series of novel 5-(substituted phenyl)-3-[(substituted phenylamino)methyl]-3H-[1,3,4]oxadiazole-2- thione derivatives were prepared and their in vitro cytotoxicity was evaluated against a panel of three cancer cell lines, namely, hepatocarcinoma HepG2, breast adenocarcinoma MCF-7, and leukemia HL-60 cells, using the widely accepted MTT assay. In general, the synthesized compounds displayed weak to moderate cytotoxic activity against the three tested cell lines. Compound 5a, which has trimethoxy substituents on both phenyl rings, exhibited the highest cytotoxic effect against all cell lines tested with IC50 values of 12.01, 7.52 and 9.7 μM against HepG2, MCF-7 and HL-60 cells, respectively. Mechanistic studies revealed that the test compounds showed a good inhibitory effect on cellular tubulin of hepatocellular carcinoma. Compound 5h was the most potent tubulin inhibitor in HepG2 cells, with 81.1 % inhibition of the original control tubulin. Moreover, the mechanism of tubulin polymerization inhibition was confirmed by immunofluorescence assay, flow cytometry, and docking study.

Nitroxyl (HNO): A Possible Strategy for Fighting Cancer

Nitroxyl (HNO), the one electron reduced form of nitric oxide (NO), shows a very distinct chemistry and biology from that of NO. Chemical profile is characterized by reactions with thiols and thiol proteins such as aldehyde dehydrogenase, glyceraldehyde 3-phosphate dehydrogenase, caspases among others. Biological profile of HNO includes cardioprotective actions especially in cases of heart failure. This short review focuses on the cytotoxic properties for HNO. Nitroxyl was found to be toxic to several cancer cell lines including lung and breast cancers. Critical thiols that control cancer cellular functions might be the target for HNO activity. The anti-tumor actions of HNO donating aspirin is also summarized.

Synthesis, cytotoxicity, docking study, and tubulin polymerization inhibitory activity of novel 1-(3,4-dimethoxyphenyl)-5-(3,4,5-trimethoxyphenyl)-1H-1,2,4-triazole-3-carboxanilides.

A series of novel 1‐(3,4‐methoxyphenyl)‐5‐(3,4,5‐trimethoxyphenyl)‐1H‐1,2,4‐triazole‐3‐carboxylic acid derivatives (4a–n) were synthesized and evaluated for their in vitro cytotoxic activity against the growth of four different human cell lines (hepatocarcinoma HepG2, breast adenocarcinoma MCF‐7, colon carcinoma DLD‐1, and leukemia HL‐60). The anilides of m‐anisidine 4e, o‐anisidine 4f, and 3,5‐difluoroaniline 4l demonstrated best results on MCF‐7 cells and mean IC50 values of 7.79, 10.79, and 13.20 µM, respectively. The compounds produced a significant reduction in cellular microtubules at a concentration of 25 µg/mL, for microtubule loss. Molecular modeling studies involving compounds 4d, 4e, 4f, and 4l with the colchicine binding site of α,β‐tubulin revealed hydrogen bonding and hydrophobic interactions with several amino acids in the colchicine binding site of β‐tubulin.

Design, synthesis and hypolipidemic activity of novel 2-(m-tolyloxy) isobutyric acid derivatives.

Novel 2-substituted isobutyric acid derivatives were synthesized and their hypolipidemic activity was evaluated in high cholesterol diet fed rat model. The amide 5a was found to decrease the levels of serum total cholesterol, LDL cholesterol and triglycerides in hyperlipidemic rats to a greater degree than the reference gemfibrozil.