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PubMedDate not supplied

Distribution of trans-4-hydroxy-2-hexenal and tandem mass spectrometric detection of its urinary mercapturic acid in the rat.

The distribution of trans-4-hydroxy-2-hexenal (t-4HH), a pyrrolizidine alkaloid metabolite and a lipid peroxidation product, was studied following the injection of [3H]t-4HH into the hepatic portal vein of male Sprague-Dawley rats. Less than 3% of the tritium label remained in the liver 24 hr after administration with levels in the other major organs correspondingly lower. The majority of recovered radioactivity (77-83%) appeared in the urine with 60-69% appearing within 8 hr after administration. Most of the urinary radioactivity (75%) was recovered in an acidic fraction following acid/base extraction. A tandem mass spectrometry technique using negative ion fast atom bombardment (FAB) ionization in combination with Mass-analyzed Ion Kinetic Energy Spectrometry verified that a C-3 mercapturic acid conjugate of trans-4-hydroxy-2-hexenal was produced as a urinary metabolite. This compound presumably forms via a Michael addition of glutathione at C-3 of t-4HH followed by hydrolysis of glutamate and glycine and acetylation to yield the mercapturic acid. While Michael additions of glutathione to t-4HH-related compounds have been observed in vitro, these results provide in vivo evidence of this mechanism.

Acetylcysteine↗
PubMedDate not supplied

[Effect of a fatty-series narcotic (ether) and a barbiturate (hexenal) on the regional distribution of the total and nutritive blood flow].

Inhalation of diethyl ether and intraperitoneal injection of hexenal in doses that provide a surgical state of anesthesia are accompanied by changes in the regional tone of the resistive blood vessels as well as by those in the ratio between the nutritive and shunting fractions of the blood flow in organs and tissues. The increase in the rate and enlargement of the area of transcapillary metabolism in the brain and myocardium (notwithstanding the decrease of the total blood flow in these organs) by means of the increased shunting fractions of the blood flow in vast skin and skeletal muscle areas are considered to be the most important events. Diethyl ether and hexenal cause different changes in the hepatic and renal hemodynamics.

Animals↗
PubMedDate not supplied

[Changes in cerebrospinal fluid pressure in neurosurgical patients during hexenal and thiopental-sodium preanesthesia].

Before undergoing operation on the brain, 30 neurosurgical patients were examined to determine the effect of hexenal (in 15) and thiopental sodium (in 15) central venous pressure were taken. Arterial pressure was measured by Korotkov's method. The cerebral perfusion pressure was calculated. Both anesthetics caused reduction of CSFP: hexenal by 91 +/- 12.1 mm water, thiopental sodium by 108 +/- 21 mm water. A smallrise of cerebral perfusion pressure was noted at the same time.

Adolescent↗
PubMedDate not supplied

Role of cellular calcium homeostasis in toxic liver injury induced by the pyrrolizidine alkaloid senecionine and the alkenal trans-4-OH-2-hexenal.

The pyrrolizidine alkaloid senecionine has been shown to be hepatotoxic, genotoxic, and cytotoxic. However, the biochemical mechanism by which senecionine produces hepatocellular toxicity remains to be elucidated. The role of calcium homeostasis in toxic liver injury was examined in isolated rat hepatocytes treated with senecionine and trans-4-OH-2-hexenal (t-4HH), a microsomal metabolite of senecionine, and appropriate cofactors. Hepatocytes treated with senecionine and t-4HH demonstrated greater cytotoxicity (leakage of lactate dehydrogenase) when incubated in the absence of extracellular Ca2+ than in its presence. Both compounds elicited an increase in cytosolic Ca2+ levels of isolated hepatocytes in the presence of extracellular Ca2+. In the following study, senecionine and t-4HH depleted intracellular glutathione levels and induced lipid peroxidation and cytotoxicity in isolated hepatocytes. Pretreatment with the thiol-group reducing agent dithiothreitol prevented depletion of intracellular glutathione and protected hepatocytes against senecionine and t-4HH-induced lipid peroxidation and cytotoxicity. Both compounds also depleted intracellular ATP and NADPH levels. These results suggest that hepatotoxicity induced by senecionine and t-4HH is not dependent on the influx of extracellular Ca2+; however, alterations in intracellular Ca2+, possibly associated with depletion of intracellular glutathione, NADPH, and ATP, may play a critical role.

Adenosine Triphosphate↗
PubMed1989

Nuclear magnetic resonance spectra and mosquito repellent properties of some oxazolidine derivatives of 5-methyl-4-hexenal.

Seven novel oxazolidines from 5-methyl-4-hexenal were synthesized, characterized, and evaluated in a cloth test system as mosquito repellents. These heterocycles were a homologous series of 3-alkanoyl-2-(4'-methyl-3'-pentenyl)oxazolidines, with substituents at N-3 ranging from acetyl to n-nonanoyl groups. Carbon-13 NMR spectroscopy at 100.6 MHz revealed that these molecules existed in deuterochloroform solution as unequal mixtures of cis (syn)- and trans (anti)-rotational isomers. At 25 degrees C, this isomerism at the amide group resulted in two detectable 13C signals for all assigned carbon atoms, except for the methyl carbons of the isopentenyl side chain. Differences in 13C chemical shifts for the methyl group at N-3 were observed up to the n-butanoyl homologue. The 13C signal assignments were aided by the distortionless enhancement by polarization transfer (DEPT) spectral editing technique. Two-dimensional carbon-hydrogen chemical shift correlation experiments aided in partially interpreting the complex proton spectra of these molecules. Repellent activity of the acetyl, trideuteroacetyl, and propionyl derivatives was observed in bioassays with three mosquito species, but the long-chain homologues were practically ineffective as mosquito repellents.

Aedes↗
PubMed2006

Bioengineering Functional Copolymers. IX. Poly[(maleic anhydride-co-hexene-1)-g-poly(ethylene oxide)].

Amphiphilic bioengineering copolymers having a combination of hydrophilic/hydrophobic linkages and polyelectrolyte behavior, along with an ability to interact with biomacromolecules, in particular with the invertase enzyme, have been synthesized by (a) complex-radical copolymerization of maleic anhydride (MA, the acceptor) and hexene-1 (H-1, the donor) monomers with benzoyl peroxide as the initiator in 1,4-dioxane at 65 degrees C under high-conversion conditions and (b) subsequent grafting (polyesterification) of synthesized poly(MA-alt-H-1) with alpha-methoxy-omega-hydroxy-poly(ethylene oxide) (PEO). Copolymerizations were also carried out in the steady state, in order to essentially reduce the effect of copolymer composition drift. The values of the monomer reactivity ratios (r(1) and r(2)) determined by using the known terminal models of Fineman-Ross (FR) and Kelen-Tüdös (KT), as well as by nonlinear regression (NLR) analysis, are: r(1) = 0.16 and r(2) = 0.30 (FR), r(1) = 0.14 and r(2) = 0.27 (KT), and r(1) = 0.15 and r(2) = 0.29 (NLR), respectively. All the copolymers and graft copolymers were characterized by FTIR spectroscopy, (1)H{(13)C} NMR spectroscopy, viscometric measurements, and chemical (acid number), thermal (DSC and TGA), and X-ray diffraction analyses. Unlike poly(MA-alt-H-1)s, PEO macrobranched graft copolymers exhibit expressed polyelectrolyte and swelling behavior in diluted and concentrated dioxane solutions, respectively. The copolymer and its PEO hyperbranched derivatives can be used as carriers for enzyme immobilization.

Enzymes, Immobilized↗
PubMed2005

Short and simple syntheses of 4-oxo-(E)-2-hexenal and homologs: pheromone components and defensive compounds of Hemiptera.

One-step syntheses of 4-oxo-(E)-2-hexenal and 4-oxo-(E)-2-octenal from commercially available 2-ethyl- and 2-butylfuran are described. A two-step synthesis of the homolog 4-oxo-(E)-2-decenal from furan is also reported. These compounds are common components of true bug defensive secretions, and recently have been identified as pheromone components for several species. The simple syntheses reported here will make these compounds readily available for further research.

Aldehydes↗
PubMed2005

Plant-plant signaling: ethylene synergizes volatile emission in Zea mays induced by exposure to (Z)-3-hexen-1-ol.

Leaf alcohol (Z)-3-hexen-1-ol (Z-3-ol) is emitted by green plants upon mechanical damage. Exposure of intact maize plants to Z-3-ol induces the emission of a volatile blend that is typically released after caterpillar feeding and attracts natural enemies of the herbivores [herbivore-induced volatile organic compounds (HI-VOC)]. Thus, it has been suggested that Z-3-ol might have a function in indirect plant defense mediating plant-plant signaling and intraplant information transfer. Here, we demonstrate that HI-VOC induction by Z-3-ol is synergized by the phytohormone ethylene. Exposure to Z-3-ol at doses of 100 and 250 nmol induced HI-VOC emission in intact maize plants. HI-VOC emissions increased by 2.5-fold when ethylene was added. The effect of ethylene was more pronounced (5.1- to 6.6-fold) when only total sesquiterpene release was considered. In contrast, ethylene alone had no inductive effect but rather decreased the emission of the constitutive maize volatile linalool. We suggest that ethylene plays a synergistic role in plant-plant signaling mediated by green leaf volatiles.

Ethylenes↗
PubMed1985

In vivo covalent binding of trans-4-hydroxy-2-hexenal to rat liver macromolecules.

Trans-4-hydroxy-2-hexenal (t-4HH), a metabolite isolated from the macrocyclic pyrrolizidine alkaloid senecionine, was tritiated to perform in vivo covalent binding studies. The in vivo binding of [3H]t-4HH to rat liver DNA, RNA and protein was investigated. No significant binding to hepatic DNA or RNA could be detected, but levels of 429 +/- 139 pmol/mg were found covalently bound to hepatic proteins 16 h after exposure. Levels as high as 916 pmol/mg protein were detected 2 h after administration of [3H]t-4HH via the hepatic portal.

Aldehydes↗
PubMed2005

Degradation of glyceraldehyde-3-phosphate dehydrogenase triggered by 4-hydroxy-2-nonenal and 4-hydroxy-2-hexenal.

Lipid peroxidation products such as 4-hydroxy-2-nonenal (HNE) may be responsible for various pathophysiological events under oxidative stress, since they injure cellular components such as proteins and DNA. Glyceraldehyde-3-phosphate dehydrogenase (GAPDH), which is a key enzyme of glycolysis and has been reported to be a multifunctional enzyme, is one of the enzymes inhibited by HNE. Previous studies showed that GAPDH is degraded when incubated with acetylleucine chloromethyl ketone (ALCK), resulting in the liberation of a 23-kDa fragment. In this study, we examined whether GAPDH incubated with HNE or other aldehydes of lipid peroxidation products are degraded similarly to that with ALCK. The U937 cell extract was incubated with these aldehydes at 37 degrees C and analyzed by Western blotting using anti-GAPDH antibodies. Incubation with HNE or 4-hydroxy-2-hexenal (HHE) decreased GAPDH activity and GAPDH protein level, and increased the 23-kDa fragment, in time- and dose-dependent manners, but that with other aldehydes did not. Gel filtration using the Superose 6 showed that the GAPDH-degrading activity was eluted in higher molecular fractions than proteasome activity. The enzyme activity was detected at the basic range of pH and inhibited by serine protease inhibitors, diisopropyl fluorophosphate and phenylmethylsulfonyl fluoride, but not by other protease inhibitors including a proteasome inhibitor, MG-132, and a tripeptidyl peptidase II (TPP II) inhibitor, AAF-CMK. These results suggest that GAPDH modified by HNE and HHE is degraded by a giant serine protease, releasing the 23-kDa fragment, not by proteasome or TPP II.

Aldehydes↗
PubMed2004

Accumulation of protein-bound 4-hydroxy-2-hexenal in spinal cords from patients with sporadic amyotrophic lateral sclerosis.

4-Hydroxy-2-hexenal (HHE) is a toxic, reactive aldehydic intermediate formed by nonenzymatic peroxidation of n-3 polyunsaturated fatty acids. The aim of this study was to determine the implication for HHE in the pathomechanism of amyotrophic lateral sclerosis (ALS) by immunohistochemical and enzyme-linked immunosorbent assay (ELISA) techniques using a mouse monoclonal IgG(1) antibody mAbHHE53 specific for protein-bound HHE. Immunohistochemical analysis on formalin-fixed, paraffin-embedded sections and frozen sections of spinal cords obtained at autopsy from 10 sporadic ALS patients and 10 age-matched control subjects demonstrated that protein-bound HHE immunoreactivity was seen and was prominent in the entire gray matter in the ALS cases and localized in the neurons, reactive astrocytes, microglial cells, and the surrounding neuropil, while the immunoreactivity was obscure or undetectable in the control cases. No significant protein-bound HHE immunoreactivity was seen in sections processed with omission of mAbHHE53 or in sections incubated with the antibody with an excess of the respective antigen. Competitive ELISA analysis on trypsin-digested protein extracts of fresh-frozen spinal cord samples disclosed a significant increase in protein-bound HHE level in the ALS cases compared with the control cases. Our results indicate that enhanced HHE formation occurs in the entire gray matter of sporadic ALS spinal cords and suggest that the selective vulnerability of motor neurons to HHE mediates the pathomechanism of this disease.

Aged↗
PubMed1996

Inhibition of glutathione S-transferase activity in human melanoma cells by alpha,beta-unsaturated carbonyl derivatives. Effects of acrolein, cinnamaldehyde, citral, crotonaldehyde, curcumin, ethacrynic acid, and trans-2-hexenal.

The glutathione S-transferase (GST) activity towards 1-chloro-2,4-dinitrobenzene in intact human IGR-39 melanoma cells was determined by the quantification by HPLC-analysis of the excreted glutathione (GSH) conjugate (S-(2,4-dinitrophenyl)glutathione; DNPSG). The major GST subunit expressed in these melanoma cells is the pi-class GST subunit P1. Using this system, the effect of exposure for 1 h to a series of alpha, beta-unsaturated carbonyl compounds at non-toxic concentrations was studied. Curcumin was the most potent inhibitor (96% inhibition at 25 microM), while 67 and 61% inhibition at 25 microM was observed for ethacrynic acid and trans-2-hexenal, respectively. Moderate inhibition was observed for cinnamaldehyde and crotonaldehyde, while no inhibition was found for citral. The reactive acrolein did not inhibit the DNPSG-excretion at 2.5 microM, the highest non-toxic concentration. Up to about 50% GSH-depletion was found after treatment with crotonaldehyde, curcumin and ethacrynic acid, however the consequences for GST conjugation are presumably small. Reversible inhibition of GST was the major mechanism of inhibition of DNPSG-excretion in melanoma cells, except in the cases of curcumin and ethacrynic acid, which compounds also inactivated GSTP1-1 by covalent modification. This was clear from the fact that depending on the dose between 30 and 80% inhibition was still observed after lysis of the cells, under which conditions reversible inhibition was is absent. Intracellular levels of DNPSG remained relatively high in the case of ethacrynic acid. It is possible that ethacrynic acid also inhibits the transport of DNPSG by inhibition of the multidrug resistance-associated protein gene encoding glutathione conjugate export pump (MRP/GS-X pump) in some way.

Acrolein↗
PubMed1998

5-Methyl-2-phenyl-2-hexenal in the scent gland secretion of male cave crickets, Troglophilus cavicola and T. neglectus (Ensifera: Rhaphidophoridae).

5-Methyl-2-phenyl-2-hexenal, a distinctly smelling compound, was identified as a constituent of the male scent gland secretion of two species of cave crickets, Troglophilus cavicola and T. neglectus. It is the first proof of a male specific exocrine compound in grasshoppers. A pheromonal function of the component could not be established; its possible biological role is discussed.

Journal Article↗
PubMed2002

A possible new disinfection by-product--2-chloro-5-oxo-3-hexene diacyl chloride (COHC)--in formation of MX by chlorinating model compounds.

MX was widely considered as one of the most important disinfection by-products (DPBs) and as the strong carcinogen in the chlorinated drinking water. Some model compounds which have been classified into four families were chlorinated at laboratory conditions. MX was produced only in the chlorinated substituted aromatic aldehydes and amino acids, while a possible new compound (COHC) was found in some substituted aromatic aldehydes, chlorinated substituted aromatic acids and phenols. Through the analysis of the peaks presented in mass spectrum, the composition and structure of the new compound are proposed as 2-chloro-5-oxo-3-hexene diacyl chloride (COHC) which could cause interference in the detection of MX. COHC has also been found in drinking water and extracted chlorinated fulvic acid solution from the sediment and water of Tai Lake, so it should bring about more attention.

Alkenes↗
PubMed2002

The interference of 2-chloro-5-oxo-3-hexene diacyl chloride (COHC) in the detection of strong mutagen MX.

The MX formation potential of some compounds belong to benzoic acids, benzoic aldehydes and phenols families was investigated. Only some structures with aldehyde group can form MX, which is inconsistent with other research. A new compound 2-chloro-5-oxo-3-hexene diacyl chloride (COHC) was found. It will seriously interfere with the detection of MX when the GC/MS instrument is operated in select ion monitoring mode because its retention time is very close to that of methylated MX and it has a set of characteristic ions m/z 199, 201, 203, which is widely used in the detection of MX. The detection of COHC has not been reported previously. However, according to its formation mechanism it will widely occur in chlorinated drinking and humic water. Due to the presence of COHC, some of the former research results on MX should be revised.

Alkenes↗
PubMed2002

Heavy-atom kinetic isotope effects, cocatalysts, and the propagation transition state for polymerization of 1-hexene using the rac-(C(2)H(4)(1-indenyl)(2))ZrMe(2) catalyst precursor.

Using 13C NMR techniques, the 12C/13C kinetic isotope effects (KIEs) for the polymerization of 1-hexene catalyzed by rac-(C2H4(1-indenyl)2)ZrMe2 in the presence of four different cocatalysts (tris(pentfluorophenyl)borane, tris(pentafluorophenyl)alane, anilinium tetrakis(pentafluorophenyl)borate, and methylalumoxane) have been determined. All cocatalysts yield similar KIEs within experimental uncertainty, with values of 1.009(1) and 1.017(2) at C1 and C2, respectively. Ab initio DFT computational modeling of the polymerization KIE indicates that alkene binding to the catalyst must be reversible, with the majority of the KIE developing in the subsequent migratory insertion reaction.

Journal Article↗
PubMed2003

A one-pot diastereoselective synthesis of cis-3-hexene-1,6-diols via an unusually reactive organozinc intermediate.

A highly diastereoselective method for the synthesis of cis-3-hexene-1,6-diols has been developed. This new reaction proceeds with excellent control of diastereoselectivity over four stereocenters and the double bond geometry. The diols are made in a one-pot procedure involving hydroboration of a terminal alkyne and transmetalation to zinc to give a divinylzinc intermediate. This intermediate undergoes reductive elimination, forming a C=C bond. In the absence of a trapping reagent, diene is liberated (70% yield); however, in the presence of ketones or aldehydes, the proposed intermediate metallocyclopentene is trapped via a double insertion of the carbonyl substrate. Workup provides the diols in 47-86% yield.

Alcohols↗