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The inhibition by naphthoquinones and anthraquinones of 2-amino-3-methylimidazo[4,5-f ]quinoline metabolic activation to a mutagen: a structure-activity relationship study (1998)

Edenharder, R. ; Speth, Claudia ; Decker, Michaela ; [et al.]

Springer

Zeitschrift für Lebensmittel-Untersuchung und -Forschung 207 (1998), S. 464-471

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ISSN: 1431-4630

Keywords: Key Words Cooked food mutagen ; Salmonella/reversion assay ; Cytochrome P-450 ; Structure-activity relationship

Source: Springer Online Journal Archives 1860-2000

Topics: Process Engineering, Biotechnology, Nutrition Technology

Notes: Abstract Nine naphthoquinones, 19 anthraquinones, and nine structurally related monoketonic compounds such as anthrone, xanthone, etc., inhibited mutagenicity induced by 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) in Salmonella typhimurium TA 98 in the presence of rat liver S9 with distinct structure-activity relationships. A carbonyl function was a prerequisite for antimutagenicity while, in general, anthraquinones (IC50 values: 2.3–〉213 nmol/ml top agar) were more potent antimutagens than structurally related monoketonic compounds (IC50 values: 25.3–94.9 nmol/ml top agar) and naphthoquinones (IC50 values: 3.7–90.7 nmol/ml top agar). The parent compounds and methyl substituted derivatives were already the most potent while introduction of polar substituents such as COOH and SO3H considerably reduced antimutagenicity. Introduction of OH functions had equivocal effects: with increasing numbers, antimutagenic potencies were concomitantly reduced; however, anthraflavic acid, chrysazin, quinizarin, and especially 5,8-dihydroxy-1,4-naphthoquinone were more potent than the parent compounds. The patterns of inhibition by quinones of 7-ethoxyresorufin-O-dealkylase activities in rat liver microsomes, linked to cytochrome P-450-dependent oxidation of IQ to N-hydroxy-IQ (N-OH-IQ), were in general identical with those obtained in the Salmonella/reversion assay except for chrysophanic acid, emodin, and some naphthoquinones which were very potent in this assay (IC50: 0.20–45.0 μM). On the other hand, mutagenicity of N-OH-IQ in S. typhimurium TA 98NR was not inhibited by nonpolar quinones (except 1,4-naphthoquinone) but rather by polar compounds and especially by hydroxyquinones (IC50 values: 5.3–106.7 nmol/ml top agar or not reached). Inhibition of mutagenic activities of IQ, 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline, 2-amino-6-methyldipyrido[1,2-a:3′,2′-d]imidazole, and 3-amino-1-methyl-5H-pyrido[4,3-b]indole by chrysazin, chrysophanic acid, physicon, and purpurin varied, but no clearcut structure-activity relationships of the mutagens were observed.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/s002170050362

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Gelchromatographie, 13. Copolymere aus vinylacetat und bismaleinimiden (1977)

Heitz, Walter ; Henke, Günther ; Platt, Karl-Ludwig ; [et al.]

Weinheim : Wiley-Blackwell

Angewandte Makromolekulare Chemie 63 (1977), S. 203-214

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ISSN: 0003-3146

Keywords: Chemistry ; Polymer and Materials Science

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology , Physics

Description / Table of Contents: Copolymerization reactivity ratios of vinyl acetate (M1) with different monomers were determined as: butyl vinyl ether (M2; r1 = 2,66, r2 = 0,069; Q2 = 0,013, e2 = -1,522), cetyl vinyl ether (M2; r1 = 3,60, r2 = 0,21; Q2 = 0,008, e2 -0,749), N,n-butyl-maleinimide (M2; r1 = 0,012, r2 = 1,74; Q2 = 1,406, e2 = 1,747), 2-Methyl-2-methoxy-3-buten (M2; r1 = 2,14, r2 = 0,14; Q2 = 0,016, e2 = -0,138). Separation of the copolymer from monomers by gel filtration is of advantage compared with the usual precipitation technique in cases where the monomers have quite different solubilities. A reaction mixture of 10-20 g can be eluted on a column of about 400 ml resulting in a solution of the pure copolymer in a solvent of choice e.g. benzene which can be easily removed by freeze drying.

Notes: Die Copolymerisationsparameter von Vinylacetat (M1) mit Butylvinyläther (M2; r1=2,66, r2=0,069; Q2=0,008, e2=-0.749), N,n-Butylmaleinimid (M2; r1=0,012, r2=1,74; Q2 = 1,406, e2 = 1,747) und 2-Methyl-2-methoxy-3-buten (M2; r1 = 2,14, r2 = 0,14; Q2 = 0,016, e2 = -0,138) wurden bestimmt. Die Abtrennung der Copolymeren vom Monomeren durch Gelfiltration is vorteilhafter als die durch Fällung, wenn die Commonomeren sehr unter-schiedliche Löslichkeitseigenschaften besitzen. Ein Ansatz von 10-20g kann an einer Säule von etwa 400ml Inhalt durch einen Trennvorgang aufgearbeitet werden.Perlcopolymerisate aus Vinylacetat und Bismaleinimiden wurden unter verschiedenen Bedingungen hergestellt, und ihre gelchromatographishen Eigenshaften untersucht. Die durch Methanolyse daraus gewonnenen Polyvinylalkoholgele zeigen in einigen Fällen eine Inversion de Molekulargewichtsabhängigkeit vom Elutionsvolumen, was durch starke Wechselwirkung zwischen Solut und Gelmatrix zu erklären ist.

Additional Material: 7 Ill.