Nahla A. Farag

Synthesis, biological evaluation and docking studies of novel benzopyranone congeners for their expected activity as anti-inflammatory, analgesic and antipyretic agents

8-Acetyl-7-hydroxy-4-phenyl-2H-benzopyran-2-one as starting material a number of 8-substituted derivatives (i.e., hydrazones 2a,b, imine 2c, chalcones 3, pyrazoles 4, 3-cyano-2-oxo-dihydropyridines 5, and/or 3-cyano-2-imino-dihydropyridines 6) were synthesized and assayed for their anti-inflammatory, analgesic and antipyretic activities. Compounds 3c, 4b and 4i showed significant anti-inflammatory, analgesic and antipyretic activities. In addition, 1, 3b, 4d, 4e, 5b, 6a, 6c, 6d, 6e showed anti-inflammatory activity, 2b, 4h, 5e exhibit analgesic activity, and 2b, 4h, 5e showed antipyretic effect. In addition, molecular modeling and docking of the tested compounds into cyclooxygenase II complexed with its bound inhibitor indomethacin (4COX) using molsoft icm 3.4-8C program was performed in order to predict the affinity and orientation of the synthesized compounds at the active site. Also, it was found that the active compounds 1, 4i, 6a-e interact with both Serine 530, and Tyrosine 385 amino acids which are the main amino acids involved in the mechanism of cyclooxygenase II inhibition. The synthesis of the pyrazole-containing new compounds 4 proved a successful hit; also, the 2-imino derivatives of 3-cyano-dihydropyridines were more successful than the 2-oxo derivatives. According to these results, we can conclude that compounds 1, 3c, 4b, 4i, and 6c appear to be the most interesting and seem potentially attractive as anti-inflammatory, analgesic, and antipyretic agents.

Phytol/Phytanic Acid and Insulin Resistance: Potential Role of Phytanic Acid Proven by Docking Simulation and Modulation of Biochemical Alterations

Since activation of PPARγ is the main target for the antidiabetic effect of TZDs, especially when it heterodimerizes with RXR, we aimed to test the potential antidiabetic effect of phytol (250 mg/kg), the natural precursor of phytanic acid, a RXR ligand and/or pioglitazone (5 mg/kg) to diabetic insulin-resistant rats. Regarding the molecular docking simulation on PPARγ, phytanic acid, rather than phytol, showed a binding mode that mimics the crystal orientation of rosiglitazone and pioglitazone, forming H bonds with the same amino acids (S289, H 323, H 449 and Y 473), and the least energy level, which emphasizes their importance for PPARγ molecular recognition, activation, hence antidiabetic activity. In addition, docking on the RXRα/PPARγ heterodimer, revealed that phytanic acid has higher binding affinity and lesser energy score on RXRα, compared to the original ligand, retinoic acid. Phytanic acid binds by 3H bonds and shares retinoic acid in arginine (R 316). These results were further supported biochemically, where oral phytol and/or pioglitazone (5 mg/kg) improved significantly glucose homeostasis, lipid panel, raised serum adiponectin level and lowered TNF-α, reaching in most cases the effect of the 10 mg/kg pioglitazone. The study concluded that the insulin sensitizing/anti-diabetic effect of phytol is mediated by partly from activation of nuclear receptors and heterodimerization of RXR with PPARγ by phytanic acid.

Design, synthesis and in vitro anti-proliferative activity of 4,6-quinazolinediamines as potent EGFR-TK inhibitors.

4-Anilino-6-substituted-quinazolines were designed, synthesized and evaluated for EGFR-TK and tumor growth inhibitory activities. The target compounds were designed with enamine ester or urea moieties appended at the C-6 of quinazoline as additional hydrogen bond acceptor functions. Most of the synthesized compounds displayed potent EGFR-TK inhibitory activity at 10 μM and the 6-ureido-anilinoquinazoline derivative 7a showed IC50 value of 0.061 μM. Moreover, six compounds were tested by National Cancer Institute (NCI), USA for their anti-proliferative activity at 10 μM in full NCI 60 cell panel. Compound 7a was further assayed for five dose molar ranges in full NCI 60 cell panel and exhibited remarkable growth inhibitory activity pattern against Non-Small Cell Lung Cancer EKVX (GI50 = 0.37 μM), NCI-H322M (GI50 = 0.36 μM), Renal Cancer A498 (GI50 = 0.46 μM), TK-10 (GI50 = 0.99 μM) and Breast Cancer MDA-MB-468 (GI50 = 1.096 μM) which are of high EGFR expression. Docking study was performed for the active compounds into ATP binding site of EGFR-TK which showed similar binding mode to gefitinib and additional binding with Cys-773 at the gatekeeper of EGFR-TK enzyme.

Design, synthesis and docking studies of new furobenzopyranones and pyranobenzopyranones as photoreagent towards DNA and as antimicrobial agents

A number of new furobenzopyranones and pyranobenzopyranones carrying an electron-withdrawing function at the position 3 are synthesized in order to obtain new photoreagents towards DNA. Our interest in this study is to investigate the effect of introduction of electron withdrawing function on the position 3 of the benzo-á-pyranone ring of linear furobenzo-á-pyranone (5,8-dimethoxypsoralen) or angular pyranobenzo-á-pyranone on the biological activity, by preparing 3-cyano, carboxylic acid, carboxylic acid ester, acid hydrazide, thiosemicarbazide, or mercaptotriazole derivatives. 5-acetyl-6-hydroxybenzofuran, and 8-acetyl-7-hydroxy-4-phenylbenzopyranone are the key starting compounds on which 3-cyano-4-methylfurobenzopyranone and 3-cyano-4-methyl pyranobenzopyranone moieties were built respectively. The photobiological activity of the newly synthesized compounds was evaluated. It looks most promising for enhancement of photoreactivity of compounds towards DNA, and a certain effect was observed in the dark determining the antimicrobial activity. Compounds 5, 6, 7, 13, 14 exhibit potential photoreactivity towards DNA, while 3-mercaptotriazole derivatives 7, 14 possess only photosensitizing activity. To investigate the antimicrobial data on structural basis, molecular modelling and docking studies of the tested compounds into the crystal structure of topoisomerase II DNA Gyrase B complexed with the natural inhibitor bearing the coumarin moiety clorobiocin (1kzn), using Molsoft ICM 3.4-8C program was performed in order to predict the affinity and orientation of the synthesized compounds at the active site. The ICM score values and hydrogen bonds formed with the surrounding amino acids show good agreement with predicted binding affinities obtained by molecular docking studies as verified by antimicrobial screening, where compounds 5, 6, 13 were the most active compounds against Bacillus subtilis, Staphylococcus aureus, and Escherichia coli. Compound 13 has good affinity with the receptor and forms six hydrogen bonds with Asp-73, and two bonds with Thr-165, compound 6 has ICM score value -85.66 and forms one hydrogen bond with Asp-73, and three with Thr-165, and compound 5 has ICM score value -53 but forms one hydrogen bond with Asp-73, and four bonds with Thr-165 which may reveal the potent antimicrobial activity referred to the natural antimicrobial Clorobiocin which forms two hydrogen bonds with Asp-73 and three with Thr-165.

Design, synthesis, 3D pharmacophore, QSAR, and docking studies of carboxylic acid derivatives as Histone Deacetylase inhibitors and cytotoxic agents

In this study, five series of (E)-6-(4-substituted phenyl)-4-oxohex-5-enoic acids IIb-f (E), (E)-3-(4-(substituted)-phenyl)acrylic acids IIIa-g (E), 4-(4-(substituted)phenylamino)-4-oxobutanoic acids VIa,b,e, 5-(4-(substituted)phenylamino)-5-oxopentanoic acids VIIa,f and 2-[(4-(substituted)phenyl) carbamoyl]benzoic acids VIIIa,e were designed and synthesized. Selected compounds were screened in vitro for their cytotoxic effect on 60 human NCI tumor cell lines. Compound IIf (E) displayed significant inhibitory activity against NCI Non-Small Cell Lung A549/ATCC Cancer cell line (68% inhibition) and NCI-H460 Cancer cell line (66% inhibition). Moreover, the final compounds were evaluated in vitro for their cytotoxic activity on HepG2 Cancer cell line in which histone deacetylase (HDAC) is overexpressed. Compounds IIc (E), IIf (E), IIIb (E), and IIIg (E) exhibited the highest cytotoxic activity against HepG2 human cancer cell lines with IC50 ranging from 2.27 to 10.71μM. In addition, selected compounds were tested on histone deacetylase isoforms (HDAC1-11). Molecular docking simulation was also carried out for HDLP enzyme to investigate their HDAC binding affinity. In addition, generation of 3D-pharmacophore model and quantitative structure activity relationship (QSAR) models were combined to explore the structural requirements controlling the observed cytotoxic properties.

Design, synthesis, and docking studies of novel benzopyrone derivatives as H1-antihistaminic agents

Two new series of 2H-1-benzopyran-2-one derivatives substituted at C-6 and/or C-7 with propanolamines, and/or piperazine propanol derivatives have been synthesized and assayed for the H(1)-histamine antagonist. Twelve of the 20 newly synthesized 4- substituted benzopyrones have shown potent antihistaminic H(1) activity. In addition, molecular modeling and docking of the tested compounds into high affinity histamine binding protein (HBP) and histamine N-methyltranseferase (HNMT) active site in complex with its bound inhibitor (diphenhydramine) was performed in order to predict the affinity and orientation of these compounds at the active sites. The ICM score values show good agreement with predicted binding affinities obtained by molecular docking studies as verified by pharmacological screening. The results showed similar orientation of the target compounds at HBP, and HNMT active sites compared with reported histamine H(1) antagonist. Also, it was concluded that in order for the compounds to be active, they must bind with both active sites of HNMT enzyme (two pockets) to inhibit it. Compounds 8c, 8i, 11g, 11i, and 11k; observe the maximum activities.

Design and Synthesis of Novel Benzopyran-2-one Derivatives of Expected Antimicrobial Activity through DNA Gyrase-B Inhibition

In an attempt to find a new class of antibacterial agents, we have synthesized thirty new coumarin (2H‐benzopyran‐2‐one) analogues. These derivatives include substituted azetidin‐2‐ones (β‐lactam) 3a–f, pyrrolidin‐2‐ones 4a–f, 2H‐1,3,4‐oxadiazoles 5a–f, and thiazolidin‐4‐ones 6a–f attached to 4‐phenyl‐2H‐benzopyran‐2‐one through an oxyacetamido or an oxymethyl bridge. The target compounds were synthesized starting from 2‐oxo‐4‐phenyl‐2H‐benzo[b]pyran‐7‐yl‐oxyacetic acid hydrazides 2a–f. The new compounds were evaluated as DNA gyrase‐B inhibitors through molecular modeling and docking techniques using the Molsoft ICM 3.4‐8C program. The synthesized compounds were also screened for antibacterial activity against four different species of Gram‐positive and Gram‐negative bacteria; as well as screening against C. albicans for antifungal activity. The molecular modeling data were in accordance with the antimicrobial screening results.

Toward discovery of mutant EGFR inhibitors; Design, synthesis and in vitro biological evaluation of potent 4-arylamino-6-ureido and thioureido-quinazoline derivatives.

A new series of 4-anilinoquinazolines with C-6 ureido and thioureido side chains and various substituents at the C-4 anilino moiety was designed, synthesized and evaluated as wild type (WT) and mutant EGFR inhibitors. Most of the compounds inhibited EGFR kinase wild type (EGFR WT) with IC50 values in the low nanomolar range (<0.495-9.05nM) and displayed more potent cytotoxic effect in BaF/3 expressing EGFR WT than reference compound gefitinib. The anti-proliferative effect of all synthesized compounds against gefitinib insensitive double mutant cell lines Ba/F3 expressing Del19/T790M and Ba/F3 expressing L858R/T790M were assayed. Compounds 4d, 6f, 7e showed significant inhibition (IC50=1.76-2.38μM) in these mutant lines and significant Her2 enzyme inhibition (IC50=19.2-40.6nM) compared to lapatinib (60.1nM). The Binding mode of compounds 6d, 6f, 7a, 7b and 8b were demonstrated. Furthermore, growth inhibition against gefitinib insensitive cell lines PC9-GR4 (Del19/T790M) were tested, compounds 6f and 7e showed about eight and three folds respectively greater potency than gefitinib. Our structure-activity relationships (SAR) studies suggested that presence of ethyl piperidino urea/thiourea at 6-position and bulky group of (3-chloro-4-(3-fluorobenzyloxy)phenyl)amino at 4-position of quinazoline may serve as promising scaffold for developing inhibitors against wild type and mutant EGFR.

Tetrahydrobenzo- and benzofurobenzopyrones as a new class of potential photoreagents toward DNA.

The synthesis and the photobiological activity of new tetrahydrobenzo- and benzofurobenzopyrone derivatives carrying at position 4 of benzopyrone ring of furobenzopyrone moiety a phenyl, or a methyl group with a linear structure or with various angular arrangements, are reported. The new compounds are characterized by having an additional cyclohexene or phenyl ring condensed at the 2, 3 double bond of the furan ring of furobenzopyrone nucleus. The syntheses were performed starting from the appropriate hydroxybenzopyrones on which the tetrahydrobenzofuran or benzofuran moiety was built, which look most promising for enhancement of photoreactivity of compounds toward DNA. All the synthesized compounds were screened for photosensitizing activity and some of them exhibited good activity also a certain effect was observed in the dark.

Synthesis, 3D pharmacophore, QSAR and docking studies of novel quinazoline derivatives with nitric oxide release moiety as preferential COX-2 inhibitors

Four novel series of 1-substituted-3-(2-methyl-4-oxo-4H-quinazolin-3-yl) urea and/or thiourea IIIa–c, 4-substituted-N-(2-methyl-4-oxo-4H-quinazolin-3-yl) benzene sulfonamide VIa–c and their NO-hybrid molecules as nitrate esters Va–c and VIIIa–c have been synthesized and evaluated for their anti-inflammatory activity in vivo and in vitro. Moreover, the nitrate ester derivatives Va–c, VIIIa–c have been assayed for the release of nitric oxide in serum using the Griess diazotization method by a nitric oxide detection kit, and the results were correlated with their gastric protective activity through the determination of the ulcer index, and histopathological investigations of the gastric mucosa under a light microscope. All of the tested compounds showed potent to moderate anti-inflammatory activity when compared to the reference drug Meloxicam. In the comparison of IIIb and its nitrate ester Vb, for the COX-2 inhibition assay, IIIb showed IC50 = 5 μM, and Vb showed IC50 = 6.86 μM with a selectivity index of 4.74 and 5.03, respectively. As for the IC50 of the COX-1 assay, it was found that the structures carrying nitric oxide moieties had less affinity to inhibit COX-1 than their corresponding starting intermediates, as in the case of compound IIIb that showed IC50 = 23.76 μM, and its nitrate ester Vb that showed IC50 = 34.6 μM; hence, it can be concluded that the alcoholic metabolites of NO esters had less tendency to inhibit COX-1, leading to less gastric ulcerative side effects. This was confirmed by measuring the nitric oxide amount release from Vb, which was found to be 28.53 μmol L−1 with the lowest ulcer index of 0.4, showing the least tendency to induce stomach ulcerations in rats. According to these results, we can conclude that quinazoline derivatives with nitric oxide release moiety seem potentially attractive as preferential COX-2 inhibitors.