Suppression of genotoxicity of carcinogens by (-)-epigallocatechin gallate.

Epidemiological evidence shows that green tea may be a factor in lowering cancer risk. We have investigated the possibility that (-)-epigallocatechin gallate (EGCG), a major polyphenol in green tea, might be an antimutagenic substance. In the Ames Salmonella test, EGCG suppressed the direct-acting mutagenicity of 3-hydroxyamino-1-methyl-5H-pyrido-[4,3-b]indole (Trp-P-2(NHOH)) and 2-hydroxyamino-6-methyldipyrido[1,2-a:3',2'-d]imidazole (Glu-P-1(NHOH)), the activated forms of food-derived carcinogens 3-amino-1-methyl-5H-pyrido[4,3-b]indole and 2-amino-6-methyldipyrido[1,2-a:3',2'-d]imidazole. EGCG was also effective in reducing the mutagenicity of Trp-P-2(NHOH) in mouse FM3A cells in culture. Furthermore, EGCG demonstrated a suppressive effect in the in vivo Drosophila mutation assays, i.e., the wing spot test, and the DNA repair test, on several carcinogens. EGCG was also effective in inhibiting DNA single-strand breaks in vitro caused by Glu-P-1(NHOH). We conclude that the mechanism of inhibition may not have resulted from direct interaction between EGCG and the mutagens, but rather from indirect interception of mutagen action by EGCG.     

Effect of dietary lipids on hepatic and intestinal monooxygenases in mice

The effect of dietary lipids on hepatic and intestinal monooxygenases was studied by feeding C57BL/6N mice (for 2 wks) diets containing 5% and 23.5% (wt/wt) olive oil or corn oil. At the end of the feeding period, we measured arylhydrocarbon hydroxylase (AHH) activity in S9 preparations from liver, small intestine, and colon; and, using the same S9 preparations from the liver, we observed the activation of the following three dietary promutagens: 2-amino-3-methylimidazo(4,5-f)quinoline, 2-amino-3,8-dimethylimidazo(4,5-f) quinoxaline, and 2-amino-6-methyldipyrido(1,2-a:3',2'-d)imidazole. The results showed that high-fat diets increased hepatic AHH activity both in corn oil and olive oil diets compared with the low-fat diets; also, a 5% corn oil diet had significantly higher AHH activity compared with the 5% olive oil diet. AHH activity was, respectively, 48.6 +/- 5.1 and 79.5 +/- 11.4 pmol 3OH-benzo[a]pyrene formed/mg/min in the 5% and 23.5% olive oil diets and 66.1 +/- 5.1 and 83.9 +/- 12.2 in the 5% and 23.5% corn oil diets; values are means +/- SE, n = 16. The results also showed a significant increase in the ability of hepatic S9 fractions from animals on high-fat diets to activate promutagens in the Salmonella/plate test. On the contrary, AHH activity in the small intestine and colon was not affected by the fat content of the diet.     

Induction of aryl hydrocarbon receptor-mediated and estrogen receptor-mediated activities, and modulation of cell proliferation by dinaphthofurans

A group of heterocyclic aromatic compounds, dinaphthofurans (DNFs), recently have been identified as potentially significant contaminants in freshwater sediments. In the present study, a battery of in vitro assays was used for detection of toxic effects of DNFs that are potentially associated with endocrine disruption and tumor promotion. Dinaphthofurans were found to act as relatively potent inducers of aryl hydrocarbon receptor (AhR)-mediated activity in the chemical-activated luciferase reporter gene expression DR-CALUX assay. The relative AhR-inducing potencies of DNFs were similar or even higher than relative potencies of unsubstituted polycyclic aromatic hydrocarbons (PAHs), with dinaphtho[1,2-b;2'3'-d]furan being the most potent AhR agonist. Two compounds, dinaphtho[2,1-b;2'3'-d]furan and dinaphtho[1,2-b;1'2'-d]furan, induced estrogen receptor (ER)-mediated activity in the estrogen receptor-mediated CALUX (the ER-CALUX) assay. Two types of potential tumor-promoting effects of DNFs were investigated, using in vitro bioassays for detection of inhibition of gap-junctional intercellular communication and detection of a release from contact inhibition. Although the acute inhibition of gap-junctional intercellular communication was not observed, all six tested DNFs were able to release rat liver epithelial WB-F344 cells from contact inhibition at concentrations as low as 100 nM. In summary, the present study indicated that DNFs can exert multiple biological effects in vitro, including induction of the AhR-mediated activity, release of cells from contact inhibition, and induction of ER-mediated activity.     

1,8-Naphthyridines VII. New substituted 5-amino[1,2,4]triazolo[4,3-a][1,8]naphthyridine-6-carboxamides and their isosteric analogues, exhibiting notable anti-inflammatory and/or analgesic activities, but no acute gastrolesivity

The [1,2,4]triazolo[4,3-a][1,8]naphthyridine-6-carboxamide derivatives 5-amino (2) or 5-alkoxy (3) substituted and the 5-amino[1,2,4]triazolo[4,3-a]quinoline-4-carboxamide derivatives (4), designed to obtain new effective analgesic and/or anti-inflammatory agents were synthesized. Ten compounds 2 and 4 showed an interesting analgesic activity: the most potent ones are 2j (36% inhibition, P<0.05) and 4b (77% inhibition, P<0.01) at 6.25 and 25mgkg(-1) doses, respectively. Compounds 2i-l and 4c showed notable anti-inflammatory properties: the most potent ones are 2i (68% inhibition, P<0.01) and 2l (42% inhibition, P<0.05) at 12.5 and 6.25mgkg(-1) doses, respectively. The replacement in compounds 2 of the N-substituted 5-amino substituents with similar alkoxy groups usually afforded less active compounds 3.     

Design and synthesis of azolopyrimidoquinolines, pyrimidoquinazolines as anti-oxidant, anti-inflammatory and analgesic activities

The 5,10-dihydro-2-thioxo-pyrimido[4,5-b]quinolines (2a-c) and its oxidized form 3 were prepared and used as key intermediates for the synthesis of thiazolo[3',2':1,2]pyrimido[4,5-b]-quinolines (5a-c), isoxazolo[5',4':4',5']thiazolo[3',2':1,2]pyrimido[4,5-b]quinolines (6a-c), 4-chloro-2-methylthio-pyrimido[4,5-b]quinoline, its amino derivatives (19-21) and 10,11,12,13-tetrahydro-5H-quino[2',3':4,5]pyrimido[6,1-b]quinazoline (22). The newly synthesized compounds were characterized by IR, NMR (1H, 13C) and mass spectral studies. Representative of the synthesized compounds was tested and evaluated for anti-oxidant, anti-inflammatory and analgesic activities. Compounds 2a-c showed the highest inhibitory anti-oxidant activity either using erythrocyte hemolysis or ABTS methods. Compounds 2a, 10b, 16, and 17a manifested the best protective effect against DNA damage induced by bleomycin. Compounds 2c, 5a, 20a, 2a, and 2b exhibited a potent anti-inflammatory activity using carrageenan-induced paw edema test in rats.     

Synthesis and antimicrobial activity of some new heterocycles incorporating antipyrine moiety

2-cyano-N-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)acetamide (1) was utilized as key intermediate for the synthesis of some new coumarin 2, pyridine 3, pyrrole 4, thiazole 7, pyrido[2',3':3,4][pyrazolo[5,1-c]triazine and aminopyrazole 9. Treatment of aminopyrazole 9 with nitrous acid, 1,3-dicarbonyl compounds, enaminone, and DMF-DMA led to the formation of pyrazolo[3,4-d]triazine 10, pyrazolo[1,5-a]pyrimidines 11, 12, 14, and pyrazolo[3,4-d]pyrimidine 13, respectively. Condensation of 9 with isatin afforded Schiff base 16. The newly synthesized compounds were characterized by IR, 1H NMR and mass spectral studies. Representative compounds of the synthesized products were tested and evaluated as antimicrobial agents.     

High affinity and selectivity of [[(arylpiperazinyl)alkyl]thio]thieno[2,3-d]pyrimidinone derivatives for the 5-HT(1A) receptor. Synthesis and structure-affinity relationships

In this work we report the affinity of new thienopyrimidinones for 5-HT(1A)Rs and the selectivity versus alpha(1)ARs. The 3-amino-2-[[3-[4-(2-methoxyphenyl)-1-piperazinyl]propyl]thio]-6-ethyl -thieno[2,3-d]pyrimidin-4(3H)-one 27 is the most potent and selective (Ki 0.19 nM, selectivity 115). Compound 31 with the N4 piperazine orthonitrophenyl nucleus instead of the orthomethoxyphenyl also shows a good affinity and selectivity (Ki 1. 46 nM, selectivity 84). The results of derivatives 28, 29 and 30 (Ki 3.28, 12.59 and 4.38 nM; selectivity 24, 4 and 5, respectively), which have, respectively, an ethyl, an allyl and an acetylamino group instead of an N3 amino group, indicate the importance of this last group for the interaction with 5-HT(1A)R. Comparison of the results for the superior homologue 53 (Ki 3.72 nM, selectivity 51) and the inferior homologue 52 (5-HT(1A) Ki 1499 nM, alpha(1)A Ki NA) of 2-[2-[4-(2-methoxyphenyl)-1-piperazinyl]ethyl]-6,7-dimethyl-8H-[1, 3,4]thiadiazolo[3,2-a]thieno[2,3-d]pyrimidin-8-one 57 (Ki 23 nM, selectivity 5) shows how important the length of the chain binding the two heterocyclic systems is in the interaction with 5-HT(1A)Rs and alpha(1)ARs.     

Derivatives of 4,6-diamino-1,2-dihydro-2-phenyl-1,2,4-triazolo[4,3-a]quinoxalin-2H-1-one: potential antagonist ligands for imaging the A2A adenosine receptor by positron emission tomography (PET)

The importance of the brain A2A adenosine receptor (A(2A)AR) in movement disorders urges the development of radiolabeled ligands for imaging those receptors by positron emission tomography (PET). This study evaluated one class of A(2A)AR antagonists, derivatives of 4-amino-6-benzylamino-1,2-dihydro-2-phenyl-1,2,4-triazolo[4,3-a]quinoxalin-2H-1-one, 10a, as agents for imaging brain A(2A)ARs by PET.. Modifications of a literature synthesis of 10a efficiently generated analogs 10b-s for pharmacological evaluation. Radioligand binding experiments showed affinities for the rat brain A(2A)AR in the low nanomolar range but similar affinities for the A1AR and substantial unspecific binding. Autoradiography employing [3H]10a, showing that high unspecific binding obscured specific binding to both the A1AR and A(2A)AR. Thus, compounds 10b-s are unsuitable as ligands for imaging brain A(2A)ARs by PET.     

Functional derivatives of 5-benzo[1, 3]dioxol-5-yl-1-methyl-1H-imidazole-2-carbaldehyde and evaluation of leishmanicidal activity

New imidazole derivatives were obtained after subjecting 5-benzo[1, 3]dioxol-5-yl-1-methyl-1H-imidazole-2-carbaldehyde to a Knoevenagel reaction. Some of these compounds exhibit significant in vitro leishmanicidal activity.     

Synthesis and in vitro antibacterial activity of novel heterocyclic derivatives of 18-nor-equilenin

Syntheses of novel heterocyclic derivatives of 18-nor-equilenin, namely, (12H-11-oxa-17-thia-15-aza-cyclopenta[a]phenanthrene-16-yl)-hydrazine (4a/b) and its fused [1,2,4]triazolo derivatives6H-5-oxa-7-thia-8,9,10a-triaza-pentaleno[4,5-a]phenanthrene (5a/b), 10-methyl-6H-5-oxa-7-thia-8,9,10a-triaza-pentaleno[4,5-a]phenanthrene (6a/b) and tetrazolo derivatives 1-substituted-6H-5-oxa-7-thia-8,9,10,10a-tetraaza-pentaleno[4,5-a]phenanthrene (7a/b) along with their antibacterial activities are reported.     

Interaction of novel condensed triazine derivatives with central and peripheral type benzodiazepine receptors: synthesis, in vitro pharmacology and modelling

Structurally related sets of triazino-quinoline, triazino-isoquinoline and pyrido-triazine derivatives were synthesised and their binding interactions with central (CBR)- and peripheral-type (PBR) benzodiazepine binding sites have been characterised. Of 33 compounds tested, a new compound, 2-(4-methylphenyl)-3H- [1,2,4] triazino [2, 3-a] quinolin-3-one (1 g) showed the lowest CBR binding inhibition constant (K(i) = 42 +/- 9 nM) and the highest CBR over PBR selectivity (>1300). All but the 4-methylphenyl (1 g) structural modifications decreased the affinity and selectivity of the parent compound, 2-phenyl-3H- [1,2,4]triazino[2,3-a]quinolin-3-one (1d) (K(i) = 69 +/- 9 nM, selectivity >890). Molecular interactions between selected ligands (standards and triazine derivatives) and alpha(1)gamma(2) subunit-interface residues in a GABA(A) receptor extracellular domain homology model have been calculated. Comparing data with calculations confirmed hydrogen bonding to gamma(2)Thr142 and hydrophobic interaction with alpha(1)His101 as being essential for high-affinity CBR binding.     

Synthesis and anticancer and anti-HIV testing of some pyrazino[1,2-a]benzimidazole derivatives

In this study, some 1-methylene-2,3-diaryl-1,2-dihydropyrazino[1,2-a]benzimidazole and some 1-(2-arylvinyl)-3-arylpyrazino[1,2-a]benzimidazole derivatives were synthesised. The structure elucidation of the compounds was performed by IR, 1H-NMR and MASS spectroscopic data and elemental analyses results. Anticancer and anti-HIV activities of the compounds were examined, however no anti-HIV activity was seen; highly notable anticancer activity was obtained. It was also observed that the compounds were more potent against leukaemia cell lines.     

New acyclic nucleosides analogues as potential analgesic, anti-inflammatory, anti-oxidant and anti-microbial derived from pyrimido[4,5-b]quinolines

Synthesis of 2-thioxopyrimido[4,5-b]quinoline 3a-c by microwave oven was used as a base to synthesis acyclic nucleosides analogue of types, 3-(penta-O-acetyl-glycosyl)-6-(4-chlorophenyl)-10-(4-chlorophenylmethylene)-7,8,9,10-tetrahydro[1,2,4]triazolo[4',3':1,2]-pyrimido[4,5-b]quinolin-4-ones (7a-c), 2-tetra-O-acetyl-glycosylhydrazon-N3-acetyl-5-(4-chlorophenyl)-9-(4-chlorophenylmethylene)-6,7,8,9-pentahydro-1H-pyrimido[4,5-b]-quinolin-4-ones (10a-c) and 3-(glycosyl)-6-(4-chlorophenyl)-10-(4-chlorophenylmethylene)-7,8,9,10-tetrahydro[1,2,4]triazolo[4',3':1,2]pyrimido[4,5-b]quinolin-4-ones (8a-c), (12a-c). The title compounds were investigated for analgesic, anti-inflammatory, anti-oxidant and anti-microbial activities. Compounds 8a,b and 12a,b exhibited highly significant activity towards gram-negative and gram-positive bacteria, showed more potent anti-inflammatory and analgesic activities than the acetylated glycoside derivatives 7a,b and 10a,b and exhibited high anti-oxidant activity when compared to the ascorbic acid.     

Tetrazolo[1,5-a]quinoline as a potential promising new scaffold for the synthesis of novel anti-inflammatory and antibacterial agents

Three series of tetrazolo[1,5-a]quinoline derivatives have been synthesized. The first series was synthesized starting by the condensation of tetrazolo[1,5-a]quinoline-4-carboxaldehyde 2 with substituted thiosemicarbazides, followed by cyclization of the resulting thiosemicarbazones 3 with malonic acid in the presence of acetyl chloride to give pyrimidyl derivatives 4a-c. The second series was prepared by the condensation of the latter compounds 4a-c with the selected aromatic aldehydes to afford the arylidene derivatives 5a-f. The third series 7a-c was synthesized by condensation of tetrazolo[1,5-a]quinoline-4-carboxaldehyde 2 with the appropriate acetophenone, followed by cyclocondensation of the formed alpha,beta-unsaturated ketones with thiourea. The newly synthesized compounds were evaluated for their anti-inflammatory and antimicrobial activities. Four compounds were proved to be as active as indomethacin in animal models of inflammation.     

Design and synthesis of 5-alkoxy-[1,2,4]triazolo[4,3-a]quinoline derivatives with anticonvulsant activity

A series of 5-alkoxy-[1,2,4]triazolo[4,3-a]quinoline derivatives were synthesized using 4-hydroxyquinolin-2(1H)-one as the starting material. Their anticonvulsant activities were evaluated by the maximal electroshock test (MES) and their neurotoxicities were measured by the rotarod test. The results of these tests demonstrated that 5-hexyloxy-[1,2,4]triazolo[4,3-a]quinoline (3f) was the most potent anticonvulsant, with median effective dose (ED(50)) of 19.0mg/kg and protective index (PI=TD(50)/ED(50)) values of 5.8 in the MES test. Compound 5-benzyloxy-[1,2,4]triazolo[4,3-a]quinoline (3j), exhibited a little weaker activity than compound 3f in controlling the seizure induced by MES test at the dose of 22.8 mg/kg, but it possessed lower neurotoxicity with PI value of 12.0, which was safer than marketed drug carbamazepine. To explain the possible mechanism of anticonvulsant activity, compound 3j was tested in pentylenetetrazole test, isoniazid test, thiosemicarbazide test, 3-mercaptopropionic acid and strychnine test.     

Organoiodine (III) mediated synthesis of 3-aryl/hetryl-5,7-dimethyl-1,2,4-triazolo[4,3-a]pyrimidines as antibacterial agents

Synthesis of some new 3-aryl/hetryl-5,7-dimethyl-1,2,4-triazolo[4,3-a]pyrimidines (3a-k) has been accomplished by the oxidation of 4,6-dimethyl-2-pyrimidinylhydrazones of various aldehydes with iodobenzene diacetate in dichloromethane. Nine new compounds (3b-g and 3i-k) were tested in vitro for their antibacterial activity. Two compounds, namely 3-(4'-pyridyl)-5,7-dimethyl-1,2,4-triazolo[4,3-a]pyrimidine (3k) and 3-(3',4'-dimethoxyphenyl)-5,7-dimethyl-1,2,4-triazolo[4,3-a]pyrimidine (3f), were associated with substantially higher antibacterial activity than some commercial antibiotics against Bacillus subtilis, Escherichia coli, Staphylococcus aureus and Salmonella typhi at MIC (minimum inhibitory concentration) i.e. 10 microg/ml.     

1,8-Naphthyridines VI. Synthesis and anti-inflammatory activity of 5-(alkylamino)-N,N-diethyl[1,2,4]triazolo[4,3-a][1,8]naphthyridine-6-carboxamides with a new substitution pattern on the triazole ring

On the basis of the good anti-inflammatory properties shown by the 9-alkyl-N,N-dialkyl-5-(alkylamino)[1,2,4]triazolo[4,3-a][1,8]naphthyridine-6-carboxamides 1, a series of analogues of such compounds, in which the 9-alkyl substituent was replaced by an ester or amide group (compounds 3a-i), was prepared and tested (inhibition of carrageenan-induced paw edema in the rat). Also two 5-(N-alkyl,N-acylamino) derivatives (compounds 4a,b) were synthesized and evaluated for the same purpose. Even though the general trend for these new [1,2,4]triazolo[4,3-a][1,8]naphthyridine derivatives was a decrease in activity compared with compounds 1, some of the new synthesized compounds exhibited still good anti-inflammatory properties.     

Novel 5,7-disubstituted 6-amino-5H-pyrrolo[3,2-b]pyrazine-2,3-dicarbonitriles, the promising protein kinase inhibitors with antiproliferative activity

New derivatives of pyrrolo[2,3-b]pyrazine were synthesized and tested on a panel of cultured human tumor cell lines. It was found that 6-amino-5-(3-chlorophenylamino)-7-(1-methyl-1H-benzo[d]imidazol-2-yl)-5H-pyrrolo[3,2-b]pyrazine-2,3-dicarbonitrile (4j) exhibited a significant antiproliferative activity: GI50 for cell lines RXF 393 (renal cancer) and BT-549 (breast cancer) were 14 and 82 nM, respectively. To identify possible molecular targets, docking of the most active compounds into the active sites of cyclin-dependent kinases was performed. Molecular modeling of the inhibitor-enzyme complexes showed the differences in the binding poses of new pyrrolo[2,3-b]pyrazine derivatives in the kinase ATP-binding site compared with known pyrrolo[2,3-b]pyrazine inhibitors called aloisines. The patterns of drug kinase interactions correlated well with antiproliferative activities of novel derivatives. Key interactions and binding mode of docked compounds are discussed.     

1,5-benzodiazepines. Part XIII. Substituted 4H-[1,2,4]triazolo[4,3-a][1,5]benzodiazepin-5-amines and 4H-imidazo[1,2-a][1,5]benzodiazepin-5-amines as analgesic,anti-inflammatory and/or antipyretic agents with low acute toxicity

The reaction of proper N,N-dialkyl-4H-[1,2,4]triazolo[4,3-a][1,5]benzodiazepin-5-amines (1) with N-chlorosuccinimide afforded their 4-chloroderivatives 3 which in turn were treated with cyclic amines to give the corresponding 4,5-diaminoderivatives 4. The N,N-dialkyl-4H-imidazo[1,2-a][1,5]benzodiazepin-5-amines (5) were prepared starting from suitable 4-(dialkylamino)-1,3-dihydro-2H-1,5-benzodiazepin-2-ones (8), through multistep synthetic routes. At the 200 mg kg(-1) os dose, some compounds 3 and 4 showed notable analgesic or anti-inflammatory activity but no antipyretic properties, whereas the 5-(dibutylamino) derivatives 5b and 5f proved to be significantly endowed with all these activities. Almost all the compounds 3, 4 and 5 did not show acute toxicity in mice up to 800 mg kg(-1) os dose.     

Investigation of commercial Mitolife as an antioxidant and antimutagen

Coronary heart disease and many types of cancer are important diseases in the world and especially in Western countries. There are biochemical activation processes for low-density lipoprotein cholesterol and genotoxic carcinogens to reactive products. In part, these also involve the generation of active oxygen and reactive oxygen species. We investigated the effect of a natural product, MitoLife, which contains a mixture of fruit and tea extracts, on the oxidation of low-density lipoprotein cholesterol and the mutagenicity of five genotoxic carcinogens, specifically, 2-acetylaminofluorene, 2-aminoanthracene, 2-amino-3-methylimidazo[4,5-f]quinoline, aflatoxin B(1), and benzo[a]pyrene. A positive antioxidant control, polyphenon 60, a concentrate of green-tea polyphenols, was used to compare the effect of MitoLife with that of polyphenon. MitoLife displayed inhibiting effects in all series of tests at slightly lower effectiveness but with the same order of magnitude as the green-tea polyphenol product. Thus, MitoLife represents another means to decrease adverse effects associated with the oxidation of low-density lipoprotein cholesterol or of a series of carcinogens, some of which are in the human environment.