Nasser Ismail

Objective Cleome genus belonging to Cleomeaceae family is used as an antidiabetic agent in Egyptian folk medicine. The current study aimed to isolated and identify the active constitutes of two species, Cleome africana and Cleome droserifolia, and to study the biological activities, such as antidiabetic, anti-inflammatory, and hepatoprotective. Materials and methods The lipid constituents of two plant species, C. africana and C. droserifolia, were extracted with petroleum ether and fractionated to acetone-insoluble fraction and acetone-soluble fraction. Molecular docking studies were carried out in isolated compounds. Antidiabetic, anti-inflammatory, and hepatoprotective activities of the promising compounds were investigated. Results and conclusion The fatty alcohols and hydrocarbons were identified from the acetone-insoluble fraction. C. africana comprises four fatty alcohols, in which tetratetracontanol is the main one, whereas C. droserifolia consists of two fatty alcohols, in which dotriacontanol is the main one. The hydrocarbons include seven compounds, with tritriacontane as the main one in both species. The acetone-soluble fraction was saponified to afford the unsaponifiable fraction, which contains in C. africana a series of n-alkanes from n-C14 to n-C31, representing 93.66%, with n-C22 as the main one, in addition to a sterol fraction, forming 5.13%, in which β-sitosterol is the main compound, and the fraction of C. droserifolia was found to contain a series of n-alkanes from n-C18 to n-C30, representing 60.46%, in which n-C30 is the main compound, besides sterols, representing about 39.54%, with campesterol as a major compound (12.46%), and finally, a triterpene fraction consisting of α-amyrin and β-amyrin. In addition, fatty acids as a mixture of eight acids (saturated and unsaturated) were found in both species; the major two acids are linoleic acid (38.99%) and palmitic acid (33.05%). Extraction of the glucosinolate (GL) constituents from the methanolic extract of C. africana led to isolation and identification of one compound (G), identified as 3-ethylsulfonyl-2,3-dimethoxypropyl GLs. Enzymatic hydrolysis of the total GLs allowed us to identify eight isothiocyanate and two thione compounds. Molecular docking of compound G with glucosidase enzyme using C-DOCKER protocol resulted in having higher docking scores relative to the lead molecule and the ligand (Glimepiride). Accordingly, molecular docking studies proved that the molecule of G compound has a promising active hits and can be used as antidiabetic through glucosidase inhibitor and also different extracts exhibited an anti-inflammatory and hepatoprotective activity.

The quinoxaline scaffold is a promising platform for the discovery of active chemotherapeutic agents. Three series of quinoxaline derivatives were synthesized and biologically evaluated against three tumor cell lines (HCT116 human colon carcinoma, HepG2, liver hepatocellular carcinoma and MCF-7, human breast adenocarcinoma cell line), in addition to VEGFR-2 enzyme inhibition activity. Compounds VIId, VIIIa, VIIIc, VIIIe and XVa exhibited promising activity against the tested cell lines and weak activity against VEGFR-2. Compound VIIIc induced a significant disruption in the cell cycle profile and cell cycle arrest at the G2/M phase boundary. In further assays, the cytotoxic effect of the highly active compounds was determined using a normal Caucasian fibroblast-like fetal lung cell line (WI-38). Compound VIIIc could be considered as a lead compound that merits further optimization and development as an anti-cancer and an apoptotic inducing candidate against the HCT116 cell line.

Epidermal growth factor receptor (EGFR) signaling pathway has been previously investigated for its significant role in the progression of different types of malignant tumors, where development of small molecules targeting EGFR is well known strategy for design of antitumor agents. Herein, we report the design and synthesis of two series of 6-(2-substitutedacetamido)-4-anilinoquinazolines (6a-x and 13a-d) as EGFR inhibitors. All the newly synthesized quinazoline derivatives were in vitro evaluated for their anti-proliferative activity towards MCF-7 (Breast Cancer) and HepG2 (Hepatocellular carcinoma) cell lines. In particular, compound 6n showed significant inhibitory activity against MCF-7 and HepG2 cell lines (IC = 3 and 16 μM, respectively), compared to that of Erlotinib (IC = 20 and 25 μM, respectively). Western blotting of 6n at MCF-7 cell line revealed the dual inhibitory activity of 6n towards diminishing the phosphorylated levels for EGFR and ERK. Also, ELISA assay confirmed ...

Imatinib possesses various mechanisms for combating cancer, making the development of imatinib analogs an attractive target for cancer research. Two series of analogs were designed and synthesized, maintaining the essential pharmacophoric features in imatinib structure. The synthesized compounds were subjected to cell-based antiproliferative assays against nonsmall lung (A549) and colon cancer cell lines. In addition, flow cytometry cell cycle and caspase-3 colorimetric assays were performed. Most compounds showed potent anticancer activity against both cell lines with IC = 0.14-5.07 μM. Three compounds demonstrated ability to reinforce cell cycle arrest at G1 stage in a manner similar to imatinib. In addition, they induced apoptosis via activation of caspase-3.

Being responsible for the development of many cancer types, EGFR (Epidermal Growth Factor Receptor) and HER2 (Human Epidermal growth factor Receptor 2) were the focus of this study where a series of novel 4-anilino-furo[2,3-d]pyrimidine derivatives was designed, synthesized and biologically evaluated. Modification of the solvent accessible 5-position side chain greatly affected the in-vitro EGFR/HER2 inhibitory activity. Three derivatives bearing 5-carboxylic acid side chain, namely the 3-chloroanilino derivative (8c), the 3-bromoaniline (8d) and the lapatinib analogue (10) demonstrated the most significant submicromolar EGFR inhibition. Surprisingly, the in-vitro assay of the ester 7h and its acid analogue 10 showed a significant variation of results between the antiproliferative activity against A549 cell line (IC50 0.5 and 21.4 μM) respectively and EGFR inhibitory activity (18% and 100%) respectively, suggesting that 7h might be a prodrug for 10. This assumption was also affirmed...

Structure-based pharmacophores were generated and validated using the bioactive conformations of different co-crystallized enzyme-inhibitor complexes for allosteric palm-1 and thumb-2 inhibitors of NS5B. Two pharmacophore models were obtained, one for palm-1 inhibitors with sensitivity = 0.929 and specificity = 0.983, and the other for thumb-2 inhibitors with sensitivity = 1 and specificity = 0.979. In addition, a quantitative structure activity relationship (QSAR) models were developed based on using the values of different scoring functions as descriptors predicting the activity on both allosteric binding sites (palm-1 and thumb-2). QSAR studies revealed good predictive and statistically significant two descriptor models (r(2 )= .837, r(2)adjusted = .792 and r(2)prediction = .688 for palm-1 model and r(2 )= .927, r(2)adjusted = .908 and r(2)prediction = .779 for thumb-2 model). External validation for the QSAR models assured their prediction power with r(2)ext = .72 and .89 for palm-1 and thumb-2, respectively. Different docking protocols were examined for their validity to predict the correct binding poses of inhibitors inside their respective binding sites. Virtual screening was carried out on ZINC database using the generated pharmacophores, the selected valid docking algorithms and QSAR models to find compounds that could theoretically bind to both sites simultaneously.

Quinoxaline derivatives, also called benzopyrazines, are an important class of heterocyclic compounds. Quinoxalines have drawn great attention due to their wide spectrum of biological activities. They are considered as an important basis for anticancer drugs due to their potential activity as protein kinase inhibitors. In this review, we focus on the chemistry of the quinoxaline derivatives, the strategies for their synthesis, their potential activities against various tyrosine kinases, and on the structure-activity relationship studies reported to date.

Many phenolic compounds found in foods and medicinal plants have shown interesting therapeutic potential and have attracted the attention of the pharmaceutical industry as promising pharmacologically active compounds in health promotion and disease prevention. Vanillin is a phenolic aldehyde, widely used as a flavoring agent in the food, pharmaceutical, and cosmetics industries. A variety of pharmacological activities has been attributed to this compound and its main metabolites, vanillic acid and vanillyl alcohol, including their anti-inflammatory ability. The relationship of the anti- inflammatory effects of vanillin, vanillic acid, and vanillyl alcohol and their actions on oxidative stress is well established. Considering that the inflammatory process is related to several pathologies, including new diseases with few therapeutic options, and limited efficiency, the search for effective treatment strategies and discovery of new anti-inflammatory agents capable of modulating inflam...

Many bis-isatins and isatins with hydrazide extension were reported to have a potential anti-proliferative effects against different cancer cell lines and cancer targets. In this study, four series of bis-isatins with hydrazide linkers were synthesized. These compounds were investigated for their antitumor activity by assessing their cytotoxic potency against HepG2, MCF-7 and HCT-116 cancer cell lines. Compound 21c possessed significant cytotoxic activity against MCF-7 (IC50 = 1.84 μM) and HCT-116 (IC50 = 3.31 μM) that surpasses the activity of doxorubicin against both cell lines (MCF-7; IC50 = 2.57 μM and HCT-116; IC50 = 3.70 μM). Cell cycle analysis and annexin V-FITC staining of MCF-7 cells treated with 21c suggested that the cytotoxic effect of the compound could be attributed to its pro-apoptotic activity.

Previously, we reported the identification of a thiazolidinedione-based adenosine monophosphate activated protein kinase (AMPK) activator, compound 1 (N-[4-({3-[(1-methylcyclohexyl)methyl]-2,4-dioxothiazolidin-5-ylidene}methyl)phenyl]-4-nitro-3-(trifluoromethyl)benzenesulfonamide), which provided a proof of concept to delineate the intricate role of AMPK in regulating oncogenic signaling pathways associated with cell proliferation and epithelial-mesenchymal transition (EMT) in cancer cells. In this study, we used 1 as a scaffold to conduct lead optimization, which generated a series of derivatives. Analysis of the antiproliferative and AMPK-activating activities of individual derivatives revealed a distinct structure-activity relationship and identified 59 (N-(3-nitrophenyl)-N'-{4-[(3-{[3,5-bis(trifluoromethyl)phenyl]methyl}-2,4-dioxothiazolidin-5-ylidene)methyl]phenyl}urea) as the optimal agent. Relative to 1, compound 59 exhibits multifold higher potency in upregulating AMPK p...

A series of novel 9-anilinoacridines was designed and their molecular docking studies into the active site were examined as topoisomerase I inhibitor. Several compounds showed significant high simulation docking score. The designed compounds were synthesized and biologically evaluated against mammary carcinoma cell line (MCF-7), where compounds 8,11e,11f,13b,14b,14e and 14f showed significant inhibitory activity at a concentration 10g/mL). It appears that the in vitro activity of compounds 8,11e,11f,13b,14b,14e and 14f were consistent with their molecular modeling results, and compound 14b showed the highest activity with IC 50 value of 7.8 µg. [Journal of American Science. 2010;6(11):148-158]. (ISSN: 1545-1003).

A novel series of quinzoline based compounds (IIIa-d, VIa-f, IXa-f) were designed, synthesized and screened for their inhibitory activity towards the PDE4B isoform. The in vivo anti-inflammatory effect of the titled compounds (IIIa-d, VIa-f, IXa-f) as well as their effect on the level of tumor necrosis factor (TNF-α) were evaluated. Among all of the synthesized compounds, IXb, IXd and IXf, exhibited good inhibitory activity against PDE4B enzyme with inhibition percentages of 42, 62 and 68%, respectively. Most of the tested compounds showed potent anti-inflammatory activity compared to indomethacin with a marked decrease in TNF-α level. The ulcerogenic effect of the tested compounds was also examined. The gastric mucosa of the tested animals remained intact after oral administration of the hit compounds. Additionally, docking study was used to explore the possible binding mode of the active compounds on the PDE4B enzyme as well as to illustrate the selectivity of the active hits on t...

A series of new 2-methyl-3-(2-piperazin-1-yl-ethyl)-pyrido[1,2-a]pyrimidin-4-one derivatives 6a-j were synthesized by a nucleophilic substitution reaction of 2-methyl-3-(2-piperazin-1-ylethyl)-pyrido[1,2-a]pyrimidin-4-one with various sulfonyl chlorides. The compounds were characterized by different spectral studies. All the compounds were evaluated for their antiproliferative effect using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay method against four human cancer cell lines (K562, Colo-205, MDA-MB 231, IMR-32) for the time period of 24 h. Among the series, compounds 6d, 6e and 6i showed good activity on all cell lines except K562, whereas the other compounds in the series exhibited moderate activity. Compound 6d could be a potential anticancer agent and therefore deserves further research.

The design and synthesis of a small library of 4-aminopyrido[2,3-d]pyrimidine derivatives is reported. The potential activity of these compounds as CDK2/Cyclin A, CDK4/Cyclin D, EGFR and anti-tumor was evaluated by cytotoxicity studies in A431a, SNU638b, HCT116 and inhibition of CDK2-Cyclin A, CDK4/Cyclin D and EGFR enzyme activity in vitro. The anti-proliferative and CDK2-Cyclin A inhibitory activity of compounds 4c and 11a

Two series of peptidomimetics were designed, prepared and evaluated for their anti-HCV activity. One series possesses a C-terminal carboxylate functionality. In the other series, the electrophilic vinyl sulfonate moiety was introduced as a novel class of HCV NS3/4A protease inhibitors. In vitro based studies were then performed to evaluate the efficacies of the inhibitors using Human hepatoma cells, with the vinyl sulfonate ester (10) in particular, found to have highly potent anti-HCV activity with an EC50=0.296μM. Finally, molecular modeling studies were performed through docking of the synthesized compounds in the HCV NS3/4A protease active site to assess their binding modes with the enzyme and gain further insight into their structure-activity relationships.

In an effort to develop ATP-competitive VEGFR-2 selective inhibitors, a series of new quinoxaline-based derivatives was designed and synthesized. The target compounds were biologically evaluated for their inhibitory activity against VEGFR-2. The design of the target compounds was accomplished after a profound study of the structure activity relationship (SAR) of type-II VEGFR-2 inhibitors. Among the synthesized compounds, 1-(2-((4-methoxyphenyl)amino)-3-oxo-3,4 dihydroquinoxalin-6-yl)-3-phenylurea (VIIa) displayed the highest inhibitory activity against VEGFR-2. Molecular modeling study involving molecular docking and field alignment was implemented to interpret the variable inhibitory activity of the newly synthesized compounds.

Nitrilimines (PhC(-):N(+):NR') generated in situ from hydrazonoyl chlorides 2a,b reacted regioselectively with 5-arylidene-2,2-dimethyl[1,3]dioxane-4,6-diones 1a-f to afford 1,3,4-triaryl-8,8-dimethyl-7,9-dioxa-1,2-diaza-spiro[4.5]dec-2-ene-6,10-diones 3a-l. In vitro vasodilation activity screening of the synthesized compounds using isolated thoracic aortic rings of male Wister rats pre-contracted with norepinephrine hydrochloride revealed considerable vasodilation activity; compounds 3f and 3j had IC(50) (concentration necessary for 50% reduction of maximal norepinephrine hydrochloride induced contracture) of 0.325, 0.321 mM, respectively. Molecular modeling, including fitting to a 3D-pharmacophore model using Discovery studio 2.1 programs and their docking into optimized alpha(1)-AR homology models as alpha(1)-AR antagonist showed high-docking score and fit values. The experimental in vitro vasodilation activity of compounds 3a-l was consistent with the molecular modeling.

ABSTRACT 1,3-Dipolar cycloaddition reaction of nitrilimines with 5-arylidene-1,3-dimethyl-2,4,6-pyrimidinetriones 1a-i afforded 7,9-dimethyl-1,3,4-triaryl-1,2,7,9-tetraaza-spiro[4.5]dec-2-ene-6,8,10-triones 3a-k in a high regioselective manner. Single crystal X-ray study of 3d added a conclusive support for the assigned structure. Potentiating effects of the synthesized compounds 3a-k (at a dose of 25 mg/kg body weight) on hypnotic action of sodium thiopental (at a dose of 75 mg/kg body weight i.p.) were investigated in vivo using Albino mice according to the standard method. Most of the tested compounds revealed promising hypnotic potentiating effects especially compounds 3k and 3e that could be nominated as short-acting hypnotics. A hypothesis of molecular modeling study, including fitting of the synthesized compounds into 3D-pharmacophore using Discovery Studio 2.5 software and their docking into optimized homology model of GABA(A)-α(1) showed good results consistent with the observed pharmacological properties.

Nitrilimines (PhC(-):N(+):NR') generated in situ from hydrazonoyl chlorides 2a,b reacted regioselectively with 5-arylidene-2,2-dimethyl[1,3]dioxane-4,6-diones 1a-f to afford 1,3,4-triaryl-8,8-dimethyl-7,9-dioxa-1,2-diaza-spiro[4.5]dec-2-ene-6,10-diones 3a-l. In vitro vasodilation activity screening of the synthesized compounds using isolated thoracic aortic rings of male Wister rats pre-contracted with norepinephrine hydrochloride revealed considerable vasodilation activity; compounds 3f and 3j had IC(50) (concentration necessary for 50% reduction of maximal norepinephrine hydrochloride induced contracture) of 0.325, 0.321 mM, respectively. Molecular modeling, including fitting to a 3D-pharmacophore model using Discovery studio 2.1 programs and their docking into optimized alpha(1)-AR homology models as alpha(1)-AR antagonist showed high-docking score and fit values. The experimental in vitro vasodilation activity of compounds 3a-l was consistent with the molecular modeling.