Abstract:
:Prolonged ingestion of Yellow Starthistle (Centaurea solstitialis) and Russian Knapweed (Centaurea repens) by horses has been shown to result in a fatal neurodegenerative disorder called equine nigropallidal encephalomalacia (ENE). Bioassay-guided fractionation of extracts from Centaurea species using the PC12 cell line have led to the identification of one of several putative agents, which may contribute to ENE, namely, the sesquiterpene lactone (SQL) repin (1), previously linked to ENE due to its abundance in C. repens. To characterize the molecular basis of repin-induced neurotoxicity, the present study was designed to identify reactive functional groups that may contribute overall to its toxicity. The reaction of repin (1) with glutathione (GSH) led to the exclusive addition of GSH to the alpha-methylenebutyrolactone affording a GSH conjugate (3b) that lacked toxicity in the PC12 cell assay, while selective reduction of the alpha-methylenebutyrolactone double bond of 1 also resulted in an analogue (2) that was devoid of toxicity relative to the parent compound. Unlike repin, analogue 2 failed to decrease cellular dopamine levels in PC12 cells, further substantiating the requirement of the alpha-methylenebutyrolactone group. Results from this study are suggestive that GSH depletion by the SQL repin may be a primary event in the etiology of ENE, increasing the susceptibility to oxidative damage.
journal_name
Chem Res Toxicoljournal_title
Chemical research in toxicologyauthors
Tukov FF,Anand S,Gadepalli RS,Gunatilaka AA,Matthews JC,Rimoldi JMdoi
10.1021/tx049864esubject
Has Abstractpub_date
2004-09-01 00:00:00pages
1170-6issue
9eissn
0893-228Xissn
1520-5010journal_volume
17pub_type
杂志文章abstract::Cyadox is a novel derivative of quinoxaline-1,4-dioxides (QdNOs) with the potential to be developed as a feed additive. However, the pharmacological and toxicological bioactive molecules of cyadox and the molecular mechanism of its pharmacological and toxic actions remain unclear. In the present study, cyadox and its ...
journal_title:Chemical research in toxicology
pub_type: 杂志文章
doi:10.1021/acs.chemrestox.8b00194
更新日期:2018-11-19 00:00:00
abstract::Inhaled glucocorticoid (GC) therapy is a vital part of the management of chronic asthma. GCs are metabolized by members of the cytochrome P450 3A family in both liver and lung, but the enzymes are differentially expressed. Selective inhibition of one or more P450 3A enzymes could substantially modify target and system...
journal_title:Chemical research in toxicology
pub_type: 杂志文章
doi:10.1021/tx100124k
更新日期:2010-08-16 00:00:00
abstract::Aflatoxin Q1 8,9-oxide was synthesized and found to yield lower levels of N7-guanyl adducts than obtained from aflatoxin B1 8,9-oxide when mixed with calf thymus DNA or Salmonella typhimurium TA 98 cells. However, when S. typhimurium TA 98 was treated with the (analogous) epoxides of aflatoxin B1, aflatoxin G1, aflato...
journal_title:Chemical research in toxicology
pub_type: 杂志文章
doi:10.1021/tx00026a009
更新日期:1992-03-01 00:00:00
abstract::Enzymatic methylation of cytosine residues in DNA, in conjunction with covalent histone modifications, establishes an epigenetic code essential for the proper control of gene expression in higher organisms. Once established during cellular differentiation, the epigenetic code must be faithfully transmitted to progeny ...
journal_title:Chemical research in toxicology
pub_type: 杂志文章
doi:10.1021/tx900027w
更新日期:2009-06-01 00:00:00
abstract::O6-Benzyl-2'-deoxyguanosine is a potential antitumor drug modulator that is intended to reduce or eliminate O6-alkylguanine-DNA alkyltransferase activity in tumors prior to treatment with genotoxic chemotherapeutic alkylating agents. The rationale for using this compound instead of the more active O6-benzylguanine and...
journal_title:Chemical research in toxicology
pub_type: 杂志文章
doi:10.1021/tx00042a008
更新日期:1994-11-01 00:00:00
abstract::The risk of potential human exposure to mixed nanomaterials in consumer, occupational, and medicinal settings is increasing as nanomaterials enter both the workplace and the marketplace. In this study, we investigated the toxicity of mixed engineered carbon black (ECB) and maghemite iron oxide (Fe(2)O(3)) nanoparticle...
journal_title:Chemical research in toxicology
pub_type: 杂志文章
doi:10.1021/tx100307h
更新日期:2010-12-20 00:00:00
abstract::The mechanism of the hepatotoxicity of the analgesic acetaminophen is believed to be mediated by covalent binding to protein; however, critical targets which effect the toxicity are unknown. It has been shown that mitochondrial respiration in vivo is inhibited in mice as early as 1 h following a hepatotoxic dose of ac...
journal_title:Chemical research in toxicology
pub_type: 杂志文章
doi:10.1021/tx950158a
更新日期:1996-03-01 00:00:00
abstract::Chemically reactive species formed from the metabolism of carboxylic acid-containing compounds have been proposed as mediators of their toxic side-effects. Two alternative metabolic pathways known to be involved in the generation of reactive acylating metabolites of carboxylic acids are acyl glucuronidation and acyl-C...
journal_title:Chemical research in toxicology
pub_type: 杂志文章
doi:10.1021/tx020013l
更新日期:2002-10-01 00:00:00
abstract::Methylmercury (MeHg) reacts readily with GSH, leading to the formation of a MeHg-SG adduct that is excreted into extracellular space through multidrug-resistance-associated protein (MRP), which is regulated by the transcription factor Nrf2. We previously reported that MeHg covalently modifies Keap1 and activates Nrf2 ...
journal_title:Chemical research in toxicology
pub_type: 杂志文章
doi:10.1021/tx5002332
更新日期:2014-10-20 00:00:00
abstract::3-Methylindole (3MI) is a preferential pneumotoxicant found in cigarette smoke. A number of lung-expressed human cytochrome P450 enzymes, including 1A1, 2F1, and 2A13, catalyze the metabolism of 3MI to reactive intermediates that fragment DNA, measured with the Comet assay to assess DNA damage, in a cytochrome P450-de...
journal_title:Chemical research in toxicology
pub_type: 杂志文章
doi:10.1021/tx100147z
更新日期:2010-11-15 00:00:00
abstract::Complex formation between nitrosoglutathione (GSNO) and Zn(II), Cd(II), and Ni(II) ions was studied by potentiometry and spectroscopic techniques. GSNO forms simple ML and ML2 type complexes (L = GSNO) with these ions. The stability of GSNO in HEPES buffer solution, pH 7.4, increased in the presence of both Zn(II) and...
journal_title:Chemical research in toxicology
pub_type: 杂志文章
doi:10.1021/tx034194i
更新日期:2004-03-01 00:00:00
abstract::Epidemiological evidence suggests a lower incidence of Parkinson's disease in smokers than in nonsmokers. This evidence, together with the lower levels of brain monoamine oxidase (MAO) activity in smokers and the potential neuroprotective properties of MAO inhibitors, prompted studies which led to the isolation and ch...
journal_title:Chemical research in toxicology
pub_type: 杂志文章
doi:10.1021/tx000224v
更新日期:2001-05-01 00:00:00
abstract::Induction of Phase II enzymes of the [Ah] gene battery by L-buthionine (S,R)-sulfoximine (BSO) and other agents was examined in mouse hepatoma Hepa-1c1c7 cells. BSO, a nonelectrophilic inhibitor of gamma-glutamylcysteine synthetase (GCS), is routinely used to examine the toxicological implications of GSH depletion. Ex...
journal_title:Chemical research in toxicology
pub_type: 杂志文章
doi:10.1021/tx00045a015
更新日期:1995-04-01 00:00:00
abstract::Mitomycin C (MMC) is a genotoxic cancer chemotherapeutic agent that reacts principally at the N2 position of guanine to form one of two predominant monoadducts, or a G-G interstrand cross-link at CpG sites, or a G-G intrastrand cross-link at GpG sites. Previous studies of MMC adduction have principally used very short...
journal_title:Chemical research in toxicology
pub_type: 杂志文章
doi:10.1021/tx960070c
更新日期:1996-10-01 00:00:00
abstract::Sulfhydration by a hydrogen sulfide anion and electrophile thiolation by reactive sulfur species (RSS) such as persulfides/polysulfides (e.g., R-S-SH/R-S-Sn-H(R)) are unique reactions in electrophilic signaling. Using 1,2-dihydroxynaphthalene-4-thioacetate (1,2-NQH2-SAc) as a precursor to 1,2-dihydroxynaphthalene-4-th...
journal_title:Chemical research in toxicology
pub_type: 杂志文章
doi:10.1021/tx500416y
更新日期:2015-05-18 00:00:00
abstract::The reaction of sodium nitroprusside (SNP) with deoxyhemoglobin (Hb) results in two distinct EPR-detectable species, the one-electron-reduced nitroprusside ion [(CN)5FeNO]3- and nitrosylhemoglobin (HbNO). In the presence of excess cyanide (CN-) only the signal for [(CN)5FeNO]3- is observed. Thus, while free CN- does n...
journal_title:Chemical research in toxicology
pub_type: 杂志文章
doi:10.1021/tx00013a012
更新日期:1990-01-01 00:00:00
abstract::5'-d(CCTATAGATATCC) was reacted with each syn-enantiomer of trans-7,8-dihydroxy 9,10-epoxy 7,8,9,10-tetrahydrobenzo[a]pyrene (syn-BPDE). The (-)-enantiomer yielded one dominating adduct, whereas the (+)-enantiomer resulted in two major adducts. As indicated by optical spectroscopic methods, the major adduct derived fr...
journal_title:Chemical research in toxicology
pub_type: 杂志文章
doi:10.1021/tx950041m
更新日期:1996-01-01 00:00:00
abstract::The C2'-oxidized abasic lesion (C2-AP) is produced in DNA that is subjected to oxidative stress. The lesion disrupts replication and gives rise to mutations that are dependent upon the identity of the upstream nucleotide. Ape1 incises C2-AP, but the 5'-phosphorylated fragment is not a substrate for the lyase activity ...
journal_title:Chemical research in toxicology
pub_type: 杂志文章
doi:10.1021/tx9003984
更新日期:2010-04-19 00:00:00
abstract::The administration of 3'-hydroxyacetanilide, a regioisomer of acetaminophen, to mice failed to produce hepatotoxicity even after the administration of diethyl maleate. In contrast, hepatotoxicity did occur when 3'-hydroxyacetanilide was administered to buthionine sulfoximine pretreated mice. Although the administratio...
journal_title:Chemical research in toxicology
pub_type: 杂志文章
doi:10.1021/tx00020a014
更新日期:1991-03-01 00:00:00
abstract::The mechanism of aromatic hydroxylation of estrogens by cytochrome P450 enzymes has been examined by comparing the oxidation of estrone with that of substrates carrying additional aromaticity such as equilenin and the structural analog 2-naphthol. Hamster liver microsomes preferentially catalyzed the conversion of est...
journal_title:Chemical research in toxicology
pub_type: 杂志文章
doi:10.1021/tx970021f
更新日期:1997-07-01 00:00:00
abstract::1,3-Butadiene (BD) is a high-volume industrial chemical and a common environmental pollutant. Although BD is classified as a "probable human carcinogen", only limited evidence is available for its tumorigenic effects in occupationally exposed populations. Animal studies show a surprisingly high sensitivity of mice to ...
journal_title:Chemical research in toxicology
pub_type: 杂志文章
doi:10.1021/tx9700681
更新日期:1997-10-01 00:00:00
abstract::Quantitative structure-activity relationships (QSAR's) are described for the rate of conjugation of a series of fluoronitrobenzenes with cytosolic as well as with two major alpha and mu class enzymes of rat and human liver, viz., glutathione S-transferases (GST) 1-1, 3-3, A1-1, and M1a-1a. For all purified enzymes stu...
journal_title:Chemical research in toxicology
pub_type: 杂志文章
doi:10.1021/tx9501804
更新日期:1996-04-01 00:00:00
abstract::Alzheimer's disease (AD) is the most common neurodegenerative disorder in the elderly population, above 65 years of age. Multiple lines of evidence confirm the central role of 40-42 residue Abeta peptides in the pathogenesis of AD, but exact mechanisms of Abeta toxicity remain unclear. Recently, evidence has accumulat...
journal_title:Chemical research in toxicology
pub_type: 杂志文章
doi:10.1021/tx900358j
更新日期:2010-02-15 00:00:00
abstract::The pharmacodynamics of rat hepatic cytochrome P450 2B (P450 2B) induction by phenobarbital (PB) and two structural congeners, dl-5-ethyl-5-phenylhydantoin (EPH) and dl-5-ethyl-5-phenyloxazolidinedione (EPO), were investigated. The in vivo induction of P450 2B was probed in F344/NCr rats by measuring immunoreactive he...
journal_title:Chemical research in toxicology
pub_type: 杂志文章
doi:10.1021/tx00032a008
更新日期:1993-03-01 00:00:00
abstract::The growth-promoting effects of estrogens in hormone-dependent tumor tissues involve receptor-mediated pathways that are well-recognized; however, the role of estrogens in tumor initiation remains controversial. Estrogen metabolites, primarily the catechol estrogens (CE's), have been implicated in tumor initiation via...
journal_title:Chemical research in toxicology
pub_type: 杂志文章
doi:10.1021/tx980128i
更新日期:1999-03-01 00:00:00
abstract::Oxidative stress is a commonly cited mechanism of toxicity of environmental agents. Ubiquitous environmental chemicals such as the diesel exhaust component 1,2-naphthoquinone (1,2-NQ) induce oxidative stress by redox cycling, which generates hydrogen peroxide (H2O2). Cysteinyl thiolate residues on regulatory proteins ...
journal_title:Chemical research in toxicology
pub_type: 杂志文章
doi:10.1021/acs.chemrestox.5b00424
更新日期:2015-12-21 00:00:00
abstract::A liquid chromatography electrospray tandem mass spectrometry (LC-ESI-MS/MS) method for the measurement of aflatoxin biomarkers in urine has been developed and validated. The two major aflatoxin-DNA adducts formed in rat tissues, aflatoxin N(7)-guanine and its imidazole ring opened derivative, 8,9-dihydro-8-(2,6-diami...
journal_title:Chemical research in toxicology
pub_type: 杂志文章
doi:10.1021/tx010063a
更新日期:2001-07-01 00:00:00
abstract::It has previously been shown that malonaldehyde forms conjugates with acetaldehyde and that these conjugates react with nucleobases forming so-called conjugate adducts. In the current study, it is shown that conjugate adducts are also formed in calf thymus DNA when incubated simultaneously with malonaldehyde and aceta...
journal_title:Chemical research in toxicology
pub_type: 杂志文章
doi:10.1021/tx060027h
更新日期:2006-07-01 00:00:00
abstract::Elevated levels of the estrone metabolite, 16α-hydroxyestrone (16αOHE1), have been linked with multiple diseases. As an electrophilic reactive metabolite, covalent binding to proteins is thought to constitute one of the possible mechanisms in the onset of deleterious health outcomes associated with 16αOHE1. Whereas ma...
journal_title:Chemical research in toxicology
pub_type: 杂志文章
doi:10.1021/acs.chemrestox.0c00171
更新日期:2020-08-17 00:00:00
abstract::Fragrances are common causes of contact allergy. Geraniol (trans-3,7-dimethyl-2,6-octadiene-1-ol) is an important fragrance terpene. It is considered a weak contact allergen and is used for fragrance allergy screening among consecutive dermatitis patients. Analogous to other monoterpenes studied, such as limonene and ...
journal_title:Chemical research in toxicology
pub_type: 杂志文章
doi:10.1021/tx700017v
更新日期:2007-05-01 00:00:00