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PubMed2003

Cytotoxic iron chelators: characterization of the structure, solution chemistry and redox activity of ligands and iron complexes of the di-2-pyridyl ketone isonicotinoyl hydrazone (HPKIH) analogues.

Di-2-pyridyl ketone isonicotinoyl hydrazone (HPKIH) and a range of its analogues comprise a series of monobasic acids that are capable of binding iron (Fe) as tridentate ( N, N, O) ligands. Recently, we have shown that these chelators are highly cytotoxic, but show selective activity against cancer cells. Particularly interesting was the fact that cytotoxicity of theHPKIH analogues is maintained even after complexation with Fe. To understand the potent anti-tumor activity of these compounds, we have fully characterized their chemical properties. This included examination of the solution chemistry and X-ray crystal structures of both the ligands and Fe complexes from this class and the ability of these complexes to mediate redox reactions. Potentiometric titrations demonstrated that all chelators are present predominantly in their charge-neutral form at physiological pH (7.4), allowing access across biological membranes. Keto-enol tautomerism of the ligands was identified, with the tautomers exhibiting distinctly different protonation constants. Interestingly, the chelators form low-spin (diamagnetic) divalent Fe complexes in solution. The chelators form distorted octahedral complexes with Fe(II), with two tridentate ligands arranged in a meridional fashion. Electrochemistry of the Fe complexes in both aqueous and non-aqueous solutions revealed that the complexes are oxidized to their ferric form at relatively high potentials, but this oxidation is coupled to a rapid reaction with water to form a hydrated (carbinolamine) derivative, leading to irreversible electrochemistry. The Fe complexes of theHPKIH analogues caused marked DNA degradation in the presence of hydrogen peroxide. This observation confirms that Fe complexes from theHPKIH series mediate Fenton chemistry and do not repel DNA. Collectively, studies on the solution chemistry and structure of theseHPKIH analogues indicate that they can bind cellular Fe and enhance its redox activity, resulting in oxidative damage to vital biomolecules.

2,2'-Dipyridyl↗
PubMed1978

Colorimetric assay of sialic acid by a methyl-3-benzothiazolinone-2-hydrazone reactant.

A colorimetric assay of sialic acid has been developed in which bound sialic acid is oxidized by periodic acid so as to quantitatively release formaldehyde. In the second step of the reaction formaldehyde reacts with methyl-3-benzothiazolinone-2-hydrazone, giving a colored compound. This method does not require a prior hydrolysis and presents the advantage of great accuracy.

Benzothiazoles↗
PubMed1983

A new peroxidase color reaction: oxidative coupling of 3-methyl-2-benzothiazolinone hydrazone (MBTH) with its formaldehyde azine. Application to glucose and choline oxidases.

Hydrogen peroxide in the presence of horseradish peroxidase effects the oxidative coupling of 3-methyl-2-benzothiazolinone hydrazone with its formaldehyde azine to form a tetraazapentamethine dye. The blue chromophore, when formed at pH 3.5 and quenched with acetone or 1 N hydrochloric acid, has an extinction coefficient of 69 +/- 2 or 55 +/- 2 mM-1 cm-1, respectively. This chromogen system has been adapted for enzymatic determinations of hydrogen peroxide and of glucose in the 10- to 45-nmol range and of choline in the 5- to 20-nmol range.

Alcohol Oxidoreductases↗
PubMed1987

Analysis of reducing sugars as their chromophoric hydrazones by high-performance liquid chromatography.

A chromophoric hydrazide, 4'-N,N-dimethylamino-4-azobenzene sulfonyl hydrazide (DABS-hydrazide), was prepared from 4'-N,N-dimethylamino-4-azobenzene sulfonyl chloride by reaction with hydrazine. Reducing sugars were derivatized with DABS-hydrazide at 50 degrees C for 120 min. The chromophoric hydrazones were separated by reversed-phase HPLC isocratically using a short column (4.6 X 50 mm) and 0.08 M acetic acid-acetone as an eluant with no sample pretreatment and were quantitated at the picomole level. This method was applied to the sugar analysis of 5 micrograms of glycoproteins. Dansyl hydrazide derivatives of sugars were also separated by this HPLC system.

Carbohydrates↗
PubMed1981

The reversible inhibition by carbonyl cyanide m-chlorophenyl hydrazone of epinephrine-stimulated lipolysis in perifused isolated fat cells.

Lipolysis stimulated in perifused isolated fat cells by 0.5 micrometers epinephrine is an ATP-dependent process which can be monitored by measuring the release of glycerol. The stimulated lipolysis is inhibited to 10 micrometers carbonyl cyanide m-chlorophenyl hydrazone (CCCP), an uncoupler of oxidative phosphorylation. If 20-micrometers glucose is continuously present in the perifusion medium during and after treatment with epinephrine and CCCP, the inhibition of the stimulated lipolysis is reversible when the CCCP is discontinued; otherwise it is not readily reversible. Since 20 micrometers 2-deoxyglucose will not substitute for glucose, metabolism of glucose beyond phosphorylation by hexokinase is concluded to be necessary in order to maintain the reversibility of the inhibition of CCCP. Substitution of 10 micrometers succinate for glucose also did not preserve the reversibility of the CCCP inhibition, and there was no significant difference in the amount of decrease of ATP in fat cells incubated with CCCP and epinephrine in the presence of glucose as compared to the decrease observed in the presence of succinate. The mechanism by which glucose maintains reversibility of the inhibition of stimulated lipolysis by CCCP is therefore not clear.

Adipose Tissue↗
PubMed1987

Inhibitory effect of ionized free intracellular calcium enhanced by ruthenium red and m-chloro-carbonylcyanide phenyl hydrazon on the evoked release of acetylcholine.

In order to understand the relationship between the free ionized calcium concentration in the axon terminals and the transmitter release we have investigated the effect of ruthenium red (RuR) and m-chloro-carbonylcyanide phenyl hydrazon (CCCP), mitochondrial uncoupler agents on the liberation of acetylcholine from myenteric plexus of guinea-pig ileum. Both compounds are able to enhance intracellular free Ca2+. In the presence of RuR and CCCP the spontaneous release of radioactivity from isolated myenteric-plexus preparation, previously loaded with (methyl-3H)-choline chloride was significantly enhanced while that evoked by electrical stimulation was decreased. Atropine did not affect the electrically evoked release in the presence of CCCP, indicating that in the effect of CCCP the presynaptic muscarinic receptors mediated negative feedback modulation does not play any role. Our findings are consistent with the hypothesis that the enhanced level of intracellular free Ca2+ enhances the spontaneous while depresses the electrically evoked release of transmitter.

Acetylcholine↗
PubMed1988

Irreversible opiate agonists and antagonists: V. Hydrazone and acylhydrazone derivatives of naltrexone.

We have synthesized a series of hydrazones and acylhydrazones of naltrexone. These substitutions had modest effects on competition of mu binding but many greatly enhanced the relative potency of the compounds for delta receptors. Increased delta affinity was most prominent with the acylhydrazones. Many of the derivatives elicited a wash-resistant inhibition of binding which was restricted to mu, not delta, binding sites. This wash-resistant inhibition of binding did not correlate with affinity, as determined by IC50 values, implying that the inhibition could not be explained simply by slow rate of dissociation due to increased affinity.

Animals↗
PubMed1987

Parasitological evaluation of curative and subcurative doses of 9-acridanone-hydrazone drugs against Schistosoma mansoni in baboons, and observations on changes in serum levels of anti-egg antibodies detected by ELISA.

Derivatives in the class of 9-acridanone-hydrazones were found to be highly active against Schistosoma mansoni in baboons. Single doses of 25 mg/kg were fully effective. Data are presented showing changes detected by ELISA in antibody levels against schistosome eggs which correlated positively with the effect of chemotherapy. This approach may help to evaluate the effects of treatment of human schistosomiasis where the detection of low egg counts is problematic.

Acridines↗
PubMed1985

In the search for new anticancer drugs. XV. Various aliphatic and aromatic hydrazones containing the N,N;N',N'-bis(1,2-ethanediyl)phosphoric diamide moiety.

The scope of the structure-anticancer activity relationship among various aliphatic and aromatic hydrazones containing the N,N,N',N'-bis(1,2-ethanediyl)-phosphoric diamide moiety was studied. A total of 19 compounds were tested in vivo, using murine lymphocytic leukemia P388. At optimum dose all these compounds were active. The highest activity was exhibited by the N,N;N',N'-bis(1,2-ethanediyl)-[N2-(p-chlorobenzylidene)-N1- hydrazin-1-yl]phosphoric triamide, N,N;N',N'-bis(1,2-ethanediyl)-N2-(p-chlorobenzylidene)-N1- methylhydrazin-1-yl]phosphoric triamide and N,N;N',N'-bis(1,2-ethanediyl)-[N2-(p-chlorobenzylidene)-N1- phenylhydrazin-1-yl]phosphoric triamide as is evidenced by the percent T/C of 212, 194 and 192, respectively. An attempt was made to correlate the anticancer activities with the corresponding lipophilicities. On the basis of the activity-lipophilicity results, it is concluded that, in general, the activity scale follows the lipophilicity scale in the reverse order, i.e. the more active compounds possess lower lipophilicity than the less active compounds.

Animals↗
PubMed1986

In the search for new anticancer drugs. XVIII. Various mono- and bis-anthraquinone hydrazones containing the N,N;N',N'-bis(1,2-ethanediyl)phosphoric diamide moiety.

The structure-anticancer activity and the activity-lipophilicity relationship of 8 mono- and bis-anthraquinone hydrazones containing the N,N;N',N'-bis(1,2-ethanediyl) phosphoric diamide moiety were evaluated. These compounds were tested in vivo, using murine lymphocytic leukemia P388. Seven of these compounds were active and one was marginal at optimum doses. The highest activity was exhibited by the bis[N,N;N',N'-bis(1,2-ethanediyl)-[N2-(1',4',5',8'-tetrahydroxy anthracenylidene)-N1-methyl hydrazin-1-yl]]-phosphoric triamide, bis[N,N;N',N'-bis(1,2-ethanediyl)-[N2-(1',4'-dihydroxy anthracenylidene)-N1-methylhydrazin-1-yl]]phosphoric triamide and bis-[N,N;N',N'-bis(1,2-ethanediyl)-[N2-(1',4',5',8'-tetrahydroxy anthracenylidene)-N1-phenylhydrazin-1-yl]]phosphoric triamide as is evidenced by their percent T/C of 183, 175 and 172, respectively. The correlation of the anticancer activities of these compounds with their lipophilicities leads to the general hypothesis that the intercalating and alkylating capabilities of a potential drug may play only a secondary role as compared to the selective permeability of the drug through normal and cancerous membranes.

Alkylating Agents↗
PubMed2006

Synthesis, in vitro and in vivo antimycobacterial activities of diclofenac acid hydrazones and amides.

Various diclofenac acid hydrazones and amides were synthesized and evaluated for in vitro and in vivo antimycobacterial activities against Mycobacterium tuberculosis. Preliminary results indicated that most of the compounds demonstrated better in vitro antimycobacterial activity (MIC: 0.0383-7.53 microM) than diclofenac (MIC: 21.10 microM) and ciprofloxacin (MIC: 9.41 microM). Among the synthesized compounds, 1-cyclopropyl-6-fluoro-8-methoxy-7-[[N4-(2-(2-(2,6-dichlorophenylamino)phenyl)acetyl)-3-methyl]-N1-piperazinyl]-4-oxo-1,4-dihydro-3-quinoline carboxylic acid (5d) was found to be the most active compound in vitro with MIC of 0.0383 microM and was more potent than first line antitubercular drug isoniazid (MIC: 0.1822 microM). In the in vivo animal model 5d decreased the bacterial load in lung and spleen tissues with 2.42- and 3.66-log10 protections, respectively, at 25 mg/kg body weight.

Amides↗
PubMed2006

Synthesis, anti-inflammatory and analgesic activity evaluation of some amidine and hydrazone derivatives.

A number of amidine derivatives (3a-i) were synthesized by condensation of cyanopyridine and cyanopyrazine with sulfonylhydrazides in the presence of sodium methoxide. 2-Acetylpyridine and 4-acetylpyridine were condensed with sulfonylhydrazides by microwave irradiation in solid phase to give corresponding hydrazones (5a-d). Indole-3-carboxaldehyde was condensed with sulfonylhydrazides by refluxing in acetic acid to give corresponding condensation product (5e and f). All the compounds, that is, 3a-i and 5a-f were purified by crystallization or by column chromatography. Structures of all the synthesized compounds are supported by correct IR, (1)H NMR, mass spectral and analytical data. Anti-inflammatory activity evaluation was carried out using carrageenin-induced paw oedema assay and compounds 3e,f and 5e exhibited good anti-inflammatory activity, that is 52%, 37% and 38% at 50 mg/kg po, respectively. Analgesic activity evaluation was carried out using acetic acid writhing assay and compounds 3a,c,e and 5f showed good analgesic activity, that is, 50%, 50%, 50% and 60% at 50 mg/kg po, respectively.

Amidines↗
PubMed2006

Synthesis, characterization, and DNA-binding properties of the Ln(III) complexes with 6-hydroxy chromone-3-carbaldehyde-(2'-hydroxy) benzoyl hydrazone.

A new ligand, 6-hydroxy chromone-3-carbaldehyde-(2'-hydroxy) benzoyl hydrazone (L), was prepared by condensation of 6-hydroxy-3-carbaldehyde chromone (CDC) with 2-hydroxy benzoyl hydrazine. Its four rare earth complexes have been synthesized and characterized on the basis of elemental analyses, molar conductivities, mass spectra, 1H NMR, thermogravimetry/differential thermal analysis (TG-DTA), UV-vis spectra, fluorescence spectra, and IR spectra. The general formula of the complexes is [LnL2.(NO3)2].NO3 [Ln=La(1), Sm(2), Dy(3), Eu(4)]. Spectrometric titration, ethidium bromide displacement experiments, and viscosity measurements indicate that Eu(III) complex and ligand, especially the Eu(III) complex, strongly bind with calf-thymus DNA, presumably via an intercalation mechanism. The intrinsic binding constants of Eu(III) complex and ligand with DNA were 3.55 x 10(6) and 1.33 x 10(6)M(-1) through fluorescence titration data, respectively. In addition, the suppression ratio for O2-* and OH* of the ligand and its complexes was studied by spectrophotometric methods. The experimental results show that La (1), Sm (2), and Eu (4) complexes are better effective inhibitor for OH* than that of mannitol. It indicates that the complexes have the activity to suppress O2-* and OH* and exhibit more effective antioxidants than ligand alone.

Antineoplastic Agents↗
PubMed2006

Hydrazones of 2-aryl-quinoline-4-carboxylic acid hydrazides: synthesis and preliminary evaluation as antimicrobial agents.

A new series of 2-arylquinoline-4-carboxylic acid hydrazide-hydrazones was synthesized using an appropriate synthetic route. All the target compounds were evaluated for their in vitro antimicrobial activity against Staphylococcus aureus as an example for Gram-positive bacteria, Escherichia coli as an example for Gram-negative bacteria, and Candida albicans as a representative of fungi. The minimum inhibitory concentration (MIC) was determined for test compounds as well as for reference standards. Among the compounds tested, compounds having nitro substituents at the arylidene moiety showed the most potent antifungal as well as antibacterial activities against E. coli. Compound 23 displayed an antifungal activity comparable to that of nystatin. However, none of the compounds demonstrated any antibacterial activity against S. aureus. Hydrophobicity of the target compounds correlated weakly with their antibacterial and antifungal activities. The most potent compounds namely, 7, 18, 19, 22, and 23 were assessed for hemolytic toxicity and found to be non-hemolytic up to a concentration of 100mug/mL. In addition, the most potent compound (23) was evaluated for in vitro cytotoxic activity against various cancer cell lines. This compound was found to display no cytotoxic activity but rather it induces the proliferation rate of Hep-G2 cells.

Anti-Bacterial Agents↗
PubMed2006

Gas chromatographic quantification of aliphatic aldehydes in freshly distilled Calvados and Cognac using 3-methylbenzothiazolin-2-one hydrazone as derivative agent.

A new precise and sensitive method was used for the quantification of aliphatic aldehydes from C5 to C11 in highly ethanolic beverages such as freshly distilled spirits. Carbonyl compounds were derivatized using 3-methylbenzothiazolin-2-one hydrazone (MBTH) and then separated and detected by gas chromatography-mass spectrometry (GC-MS). Selective mass spectrometric detection of molecular ions of derivatives was performed to obtain a good sensibility (0.2-1.2 microg l(-1)) and a good selectivity. For a concentration of 20 microg l(-1), relative standard deviations were lower than 10% except for heaviest compounds (decanal and undecanal) where RSD were between 11 and 13%. The concentrations of aliphatic aldehydes were determined in nine samples of freshly distilled Calvados and two samples of freshly distilled Cognac with highest concentrations reported for 3-methylbutanal (from 170 to 1220 microg l(-1) in Calvados and from 1540 to 5500 microg l(-1) in Cognac). 3-Methylbutanal and hexanal, due to their low detection thresholds, could be important olfactive markers of these two products. Less than 1h30 is required to quantify the nine studied aliphatic aldehydes in freshly distilled spirits.

Alcoholic Beverages↗
PubMedDate not supplied

Synthesis and biological activities of diflunisal hydrazide-hydrazones.

Several diflunisal hydrazide-hydrazone derivatives namely 2',4'-difluoro-4-hydroxybiphenyl-3-carboxylic acid [(5-nitro-2-furyl/substitutedphenyl)methylene] hydrazide (3a-o) have been synthesised. Methyl 2',4'-difluoro-4-hydroxybiphenyl-3-carboxylate (1) and 2',4'-difluoro-4-hydroxybiphenyl-3-carboxylic acid hydrazide (2) were also synthesised and used as intermediate compounds. All synthesised compounds were screened for their antimycobacterial activity against Mycobacterium tuberculosis H37 Rv, antimicrobial activities against various bacteria, fungi and yeast species. Compound 3a have shown activity against Staphylococcus epidermis HE-5 and Staphylococcus aureus HE-9 at 18.75 and 37.5 microg mL(-1), respectively. Compound 3o have exhibited activity against Acinetobacter calcoaceticus IO-16 at a concentration of 37.5 microg mL(-1), whereas Cefepime, the drug used as standard, have been found less active against the microorganisms mentioned above. The synthesised compounds were found to provide 12-34% inhibition of mycobacterial growth of M. tuberculosis H37 Rv in the primary screen at 6.25 microg mL(-1). Anticonvulsant activity of the compounds were also determined by maximal electroshock (MES) and subcutaneous metrazole (scMET) tests in mice and rats following the procedures of antiepileptic drug development (ADD) program of the National Institutes of Health (NIH). Compound 3k showed 25% protection against MES induced seizures in p.o. rat screening at a dose level of 30 mg kg(-1) whereas 3n and 3o showed neurotoxicity after 4 and 0.5 h at a dose level of 100 and 300 mg kg(-1), respectively.

Animals↗
PubMed2004

Synthesis and antifungal activity of cholesterol-hydrazone derivatives.

A series of hydrazones synthesized from various cholesterol derivatives were evaluated for their in vitro antimicrobial properties against human pathogens. The activity was highly dependent on the structure of the different compounds involved. The best results have been obtained with tosylhydrazone cholesterol derivatives 8 and 9 exhibiting activities against Candida albicans (CIP 1663-80) at a concentration of 1.5 microg/ml.

Anti-Bacterial Agents↗
PubMed2006

Synthesis and antiproliferative activity of benzo[d]isothiazole hydrazones.

Several benzo[d]isothiazole hydrazones have been evaluated for their potential antiretroviral activity. Since a number of these compounds were found to be inactive against viruses, but showed cytotoxicity at micromolar concentrations against the human CD4+ lymphocytes (MT-4) that were used to support HIV-1 growth, they were further tested for antiproliferative activity. The compounds resulted as being cytotoxic for MT-4 cells and new derivatives which were rationally designed and synthesized, were tested for antiproliferative activity against several leukaemia and solid tumour cell lines. In addition, these compounds were evaluated against "normal" cell lines. Compound 2h proved to be the most active compound and the fragment -CO-NH-N=CH-2-hydroxyphenyl was identified as being very important for biological activity, suggesting intramolecular hydrogen bond formation or favourable mutual disposition between two important centres in the pharmacophore. 1H-NMR spectra have been explained with the support of a conformational analysis.

Antineoplastic Agents↗