ABSTRACT ChemInform is a weekly Abstracting Service, delivering concise information at a glance t... more ABSTRACT ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
A series of chromene derivatives was synthesized and evaluated for their in vitro and ex vivo 5-l... more A series of chromene derivatives was synthesized and evaluated for their in vitro and ex vivo 5-lipoxygenase (5-LO) inhibitory activity. These compounds were prepared by condensation of appropriate salicyl aldehydes with alpha, beta-unsaturated carbonyl compounds, followed by transformation to the corresponding hydroxamic acids or N-hydroxyureas. Placement of phenoxy or p-fluorophenoxy substituents at the 6 position of the chromene ring led to a dramatic increase in the in vitro potency as demonstrated by the guinea pig PMN 5-LO assay. Chromene hydroxamic acids, in general, behaved poorly in the ex vivo dog model. On the other hand, replacement of the hydroxamic acid function with N-hydroxyurea yielded potent and long-lasting 5-LO inhibitors in the dog model. In most cases, the oral efficacy of the chromene N-hydroxyureas correlated very well with their in vitro activity. Compounds 43 (CGS 23885) and 55 (CGS 24891) are among the most potent inhibitors prepared, showing IC50 values of 48 and 51 nM, respectively. The values for the duration of action (DA) for compounds 43 and 55 are 21 and 20 h, respectively, following intravenous (i.v.) administration of 1.0 mg/kg. In the oral (po) experiments, 43 and 55 have DA's of 14 and 15 h, respectively, at a 1.0 mg/kg dose. In both iv and po experiments, 43 and 55 showed sustained maximal inhibition (> 95%) at earlier time points. The oral ED50 values of 43 and 55 in the ex vivo dog model are 0.23 and 0.23 mg/kg, respectively, at 6.0 h, and 2.37 and 1.63 mg/kg, respectively, at 24 h. Compound 43, which inhibits sheep seminal vesicle cyclooxygenase (CO) with an IC50 value of 36 microM, was shown to be a selective 5-lipoxygenase inhibitor in the ex vivo study. These compounds compare favorably with zileuton (A-64077) in all the parameters examined.
4-Methyl-5-pyrazinyl-3H-1,2-dithiole-3-thione (oltipraz) and several other dithiolethiones protec... more 4-Methyl-5-pyrazinyl-3H-1,2-dithiole-3-thione (oltipraz) and several other dithiolethiones protect against the acute toxicities of many xenobiotics and are effective inhibitors of experimental carcinogenesis. These protective effects are mediated, in part, through elevation of glutathione S-transferase, NAD(P)H: quinone reductase and UDP-glucuronosyltransferase activities in the liver and other target tissues. The induction of these phase 2 enzymes by oltiprax results from enhanced transcription. In the present study, the molecular mechanisms of these inductions were analyzed utilizing a construct containing a 41 bp enhancer element derived from the 5'-upstream region of the mouse liver glutathione S-transferase Ya subunit gene ligated to the 5' end of the isolated promoter region of this gene, and inserted into a plasmid containing a human growth hormone reporter gene. When this construct was transfected into murine Hepa 1c1c7 hepatoma cells, the concentrations of 25 dithiolethiones and related analogs required to double growth hormone production were determined and spanned a range nearly three orders of magnitude. Concentrations of dithiolethiones required to double the specific activity of NAD(P)H: quinone reductase were also determined in Hepa 1c1c7 cells. There was a positive correlation (r = 0.78) between the potencies of the 21 active compounds as inducers of both NAD(P)H: quinone reductase activity and growth hormone production. Moreover, no dithiolethiones were inactive in only one system. It is probable, therefore, that the induction of NAD(P)H: quinone reductase and other phase 2 enzymes by oltipraz and other dithiolethiones is mediated entirely through the 41 bp enhancer element.
... All rights reserved 0960-894X/94 $6.00+0.00 0960-894X(94)E0006-Z BENZOXEPIN AND BENZOTHIEPIN ... more ... All rights reserved 0960-894X/94 $6.00+0.00 0960-894X(94)E0006-Z BENZOXEPIN AND BENZOTHIEPIN DERIVATIVES AS POTENT, ORALLY ACTIVE INHIBITORS OF 5-LIPOXYGENASE Yoshitaka Saton,* Adam H. Ubby ... (h) Weinblatt, M.; Kermer, J.; Helfgott, S.; ...
ABSTRACT ChemInform is a weekly Abstracting Service, delivering concise information at a glance t... more ABSTRACT ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
A series of chromene derivatives was synthesized and evaluated for their in vitro and ex vivo 5-l... more A series of chromene derivatives was synthesized and evaluated for their in vitro and ex vivo 5-lipoxygenase (5-LO) inhibitory activity. These compounds were prepared by condensation of appropriate salicyl aldehydes with alpha, beta-unsaturated carbonyl compounds, followed by transformation to the corresponding hydroxamic acids or N-hydroxyureas. Placement of phenoxy or p-fluorophenoxy substituents at the 6 position of the chromene ring led to a dramatic increase in the in vitro potency as demonstrated by the guinea pig PMN 5-LO assay. Chromene hydroxamic acids, in general, behaved poorly in the ex vivo dog model. On the other hand, replacement of the hydroxamic acid function with N-hydroxyurea yielded potent and long-lasting 5-LO inhibitors in the dog model. In most cases, the oral efficacy of the chromene N-hydroxyureas correlated very well with their in vitro activity. Compounds 43 (CGS 23885) and 55 (CGS 24891) are among the most potent inhibitors prepared, showing IC50 values of 48 and 51 nM, respectively. The values for the duration of action (DA) for compounds 43 and 55 are 21 and 20 h, respectively, following intravenous (i.v.) administration of 1.0 mg/kg. In the oral (po) experiments, 43 and 55 have DA's of 14 and 15 h, respectively, at a 1.0 mg/kg dose. In both iv and po experiments, 43 and 55 showed sustained maximal inhibition (> 95%) at earlier time points. The oral ED50 values of 43 and 55 in the ex vivo dog model are 0.23 and 0.23 mg/kg, respectively, at 6.0 h, and 2.37 and 1.63 mg/kg, respectively, at 24 h. Compound 43, which inhibits sheep seminal vesicle cyclooxygenase (CO) with an IC50 value of 36 microM, was shown to be a selective 5-lipoxygenase inhibitor in the ex vivo study. These compounds compare favorably with zileuton (A-64077) in all the parameters examined.
4-Methyl-5-pyrazinyl-3H-1,2-dithiole-3-thione (oltipraz) and several other dithiolethiones protec... more 4-Methyl-5-pyrazinyl-3H-1,2-dithiole-3-thione (oltipraz) and several other dithiolethiones protect against the acute toxicities of many xenobiotics and are effective inhibitors of experimental carcinogenesis. These protective effects are mediated, in part, through elevation of glutathione S-transferase, NAD(P)H: quinone reductase and UDP-glucuronosyltransferase activities in the liver and other target tissues. The induction of these phase 2 enzymes by oltiprax results from enhanced transcription. In the present study, the molecular mechanisms of these inductions were analyzed utilizing a construct containing a 41 bp enhancer element derived from the 5'-upstream region of the mouse liver glutathione S-transferase Ya subunit gene ligated to the 5' end of the isolated promoter region of this gene, and inserted into a plasmid containing a human growth hormone reporter gene. When this construct was transfected into murine Hepa 1c1c7 hepatoma cells, the concentrations of 25 dithiolethiones and related analogs required to double growth hormone production were determined and spanned a range nearly three orders of magnitude. Concentrations of dithiolethiones required to double the specific activity of NAD(P)H: quinone reductase were also determined in Hepa 1c1c7 cells. There was a positive correlation (r = 0.78) between the potencies of the 21 active compounds as inducers of both NAD(P)H: quinone reductase activity and growth hormone production. Moreover, no dithiolethiones were inactive in only one system. It is probable, therefore, that the induction of NAD(P)H: quinone reductase and other phase 2 enzymes by oltipraz and other dithiolethiones is mediated entirely through the 41 bp enhancer element.
... All rights reserved 0960-894X/94 $6.00+0.00 0960-894X(94)E0006-Z BENZOXEPIN AND BENZOTHIEPIN ... more ... All rights reserved 0960-894X/94 $6.00+0.00 0960-894X(94)E0006-Z BENZOXEPIN AND BENZOTHIEPIN DERIVATIVES AS POTENT, ORALLY ACTIVE INHIBITORS OF 5-LIPOXYGENASE Yoshitaka Saton,* Adam H. Ubby ... (h) Weinblatt, M.; Kermer, J.; Helfgott, S.; ...
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