(n.) A hydrocarbon, C6H4.C2O2.C6H4, subliming in shining yellow needles. It is obtained by oxidation of anthracene.
Example Sentences:
(1) We have studied the effects of clinically useful anthraquinones on the cardiac sarcoplasmic reticulum calcium-release channel.
(2) Since the mutagenic compounds isolated are anthraquinone derivatives with the exception of compound 1, structure-mutagenicity relationships of the anthraquinones were also studied.
(3) We have conducted stopped-flow kinetics association and dissociation experiments on the interaction of these anthraquinones with calf thymus DNA and with DNA polymers with alternating AT and GC base pairs to experimentally determine the binding mode and how the threading mode affects intercalation rates relative to similarly substituted classical intercalators.
(4) The results were compared with that of versicolorin A, an anthraquinone with bisfuran ring, which had been proved to be genotoxic on this assay.
(5) From lettuce and string beans quercetin was isolated (after chemical hydrolysis) and in rhubarb emodin, an anthraquinon, was detected.
(6) Mitoxantrone is an anthraquinone antineoplastic agent with structural similarities to doxorubicin.
(7) A few were positive for phlobatannins and anthraquinones.
(8) The maximum content of antraquinones on a fresh weight basis was 0.334 percent, which is higher than the content of total anthraquinones in the dry seeds.
(9) 1,4-Diamino-substituted anthraquinone antitumor agents (mitoxantrone and ametantrone) and structurally related 1,5- and 1,8-diamino-substituted compounds (AM1 and AM2) were tested for their ability to photosensitize human leukemic cells in culture.
(10) Doxorubicin enhances the binding of [3H]ryanodine to SR membranes and soluble receptor preparations and induces Ca2+ release from SR vesicles in a highly Ca2(+)-dependent manner, suggesting that anthraquinones promote the open state of the junctional Ca2+ release channel by increasing the affinity of the Ca2+ activator site for Ca2+.
(11) The carbonate- and alkali-soluble pigments have been further separated by chromatography and shown to consist of anthraquinone derivatives.
(12) The anthraquinones danthron, doxorubicin and emodin were poorly metabolized in this system.
(13) Ca(2+)-calmodulin-dependent myosin light chain kinase (MLCK) is inhibited by a range of di-, tri- and tetrahydroxylated anthraquinones (IC50 values 2 to 53 microM), the most potent inhibitors being the more polar compounds, namely mitoxantrone (IC50 2 microM) and emodin (1,3,8-trihydroxy-6-methylanthraquinone) (IC50 8 microM).
(14) These results agree with recent observations on the effects of senna in rats and mice, and do not support earlier claims that myenteric neurons are killed by anthraquinone purgatives.
(15) Sodium 2-hydroxy-anthraquinone sulphate and anthraquinone-2-suphonate were also active as antifeedants for the species tested.
(16) Three compounds, [[2-[[2-(anthraquinon-1- ylamino)ethyl]amino]ethyl]amine-N,N']dichloroplatinum(II), [[2-[[3-(anthraquinon-1-ylamino)propyl]amino]ethyl]amine- N,N']dichloroplatinum(II), and [[2-[[3-anthraquinon-1- yloxy)propyl]amino]ethyl]amine-N,N']dichloroplatinum(II), were as active in vitro as cisplatin (ED50 = 2-4 x 10(-7) M) while on a molar basis their acute in vivo toxicity was significantly lower than that of cisplatin.
(17) Components S 383-O and S 383-A were identified as known derivatives of anthraquinone and naphthacenequinone, respectively, previously isolated from cultures of other blocked mutants of S. galilaeus strains.
(18) The naturally-occurring anthraquinones (AQs), alizarin (1,2-dihydroxyanthraquinone) and lucidin (1,3-dihydroxy-2-hydroxymethylanthraquinone), were incubated with DNA in the presence of S9 mix.
(19) The anthraquinone was shown to enhance binding to a complementary RNA when linked to the 3' and 5' end.
(20) The in vitro microbial degradation and the urinary excretion and biliary secretion in rats of two anthraquinone glycosides (sennosides A and B) and four aglycones (sennidins A and B, rhein, and danthron) were studied using a high performance liquid chromatographic system with gradient elution and amperometric detection.
Quinone
Definition:
(n.) A crystalline substance, C6H4O2 (called also benzoketone), first obtained by the oxidation of quinic acid and regarded as a double ketone; also, by extension, any one of the series of which quinone proper is the type.
Example Sentences:
(1) The thiol-conjugating capacity of quinones may, however, be applied to reduce the tissue-damaging effects of stimulated neutrophils.
(2) The effect of dicoumarol on glucuronidation of 3-OH-benzo(a)pyrene (BP) appears to be due to inhibition of UDPglucuronosyltransferase (UDPGT) and not to an inhibited DT-diaphorase (NAD(P)H:quinone oxidoreductase); to date the only enzyme known to be inhibited by dicoumarol.
(3) The coupled dienone-phenol re-arrangement and keto-enol tautomerism of this quinone methide produce the observed 3,4-dihydroxybenzaldehyde.
(4) Moreover, it seems unlikely that quinones are involved directly (e.g.
(5) The second-order rate constants appear to be at least 3 orders of magnitude lower than the second-order constants for quenching of the fluorescent probes; this is taken as a clear indication that ubiquinone diffusion is not the rate-determining step in the quinone-enzyme interaction.
(6) 15 human tumour cell lines (lung, breast and colon) have been evaluated for their sensitivity to the quinone based anti-cancer drugs Mitomycin C, Porfiromycin, and EO9 (3-hydroxymethyl-5-aziridinyl-1-methyl-2-(IH-indole-4,7-dione)prop-beta- en-alpha-ol).
(7) These studies provide evidence that GHB exerts cytotoxicity specifically for cells that by their content of tyrosinase convert the phenol to the quinone.
(8) Comparison of these two activities for both the quinone and hydroquinone showed that the hydroquinone form had superior activities.
(9) Bis(alkylthio)quinones 4a-d and 5a-d, and corresponding hydroquinones 9b-d exhibited high activities both in vitro and in vivo.
(10) It seems that quinone pigments, especially 2-oxyjuglone, react with complex I faster than it follows from their approximate values of one-electron reduction potential calculated from their reactivities with flavocychrome b2 and adrenodoxin.
(11) Formation of catechol from quinone by cyst extracts was observed spectrophotometrically and chromatographically.
(12) The present studies were conducted to evaluate the relative effect of the parent chemical BHT and two of its major oxidative metabolites, 2,6-di-tert-butyl-4-hydroxymethylphenol (BHT-BzOH) and 2,6-di-tert-butyl-1,4-benzoquinone (BHT-quinone), on DMBA-induced rat mammary tumorigenesis and on the formation of rat mammary DMBA-DNA adducts in vivo.
(13) Quinones play a major role in allergic contact dermatitis caused by plants.
(14) The urushiol analogs 5-pentadecylresorcinol (PDR) and 3-heptadecylveratrole (HDV) which cannot form o-quinones were found to be ineffective sensitizers as well.
(15) Toxicity of quinone(di)imines to hepatocytes and CHO cells was not related to superoxide anion radical formation, and toxicity to CHO cells was not affected by exclusion of oxygen during exposure of the cells to the compounds.
(16) The activity of cytochrome P-450 reductase, which reduces quinones to hydroquinones in the estrogen redox cycle, was 6-fold higher in liver than in kidney of both control and estrogen-treated animals.
(17) The interaction of pyrroloquinoline quinone (PQQ) with amino groups was followed by measuring the capacity of adducts to reduce nitroblue tetrazolium (NBT).
(18) The menadione-induced quinone reductase was isolated from the cytoplasmic fraction of induced cells.
(19) Hepa 1c1c7 murine hepatoma cells are plated in 96-well microtiter plates, grown for 24 h, and exposed to inducing agents for another 24 h. The cells are then lysed and quinone reductase activity is assayed by the addition of a reaction mixture containing an NADPH-generating system, menadione (2-methyl-1,4-naphthoquinone), and MTT [3-(4,-5-dimethylthiazo-2-yl)-2,5-diphenyltetrazolium bromide].
(20) quinone complex (X) was chemically reduced (state [PIX-]; P is the reaction center bacteriochlorophyll dimer, I is the long wavelength bacteriopheophytin), and compares these with the fluorescence observed when all the traps are open (state [PIX]) and with the fluorescence observed when all the traps are closed (state [P+IX]).