Benzo metabolism

Benzo[/i]quinoIines hydrogenation, 2, 329 Skraup synthesis, 2, 467 structure, 2, 110 synthesis, 2, 468 from benzindoline, 2, 491 from propargyinaphthylamines, 2, 416 Benzoquinolinium cations metabolism, 1, 234 Benzoquinolinium salts Beyer synthesis, 2, 474 Benzoquinolinones synthesis, 2, 448... 

Benzo[b]thiophene-2,3-quinone, 5-chloro-oxidation, 4, 824 Benzothiophenes, 4, 863-934 biological activity, 4, 911-913 intramolecular acylation, 4, 761 mass spectrometry, 4, 739 metabolism, 1, 242 phosphorescence, 4, 16 reactivity, 4, 741-861 spectroscopy, 4, 713-740 structure, 4, 713-740 substituents reactivity, 4, 796-839... 

FIGURE 2.6 The procarcinogen benzo[a]pyrene oriented in the CYPlAl active site (stereo view) via n- n stacking between aromatic rings on the substrate and those of the complementary amino acid side chains, such that 7,8-epoxidation can occur. The substrate is shown with pale lines in the upper structures. The position of metabolism is indicated by an arrow in the lower structure (after Lewis 1996). 

Warshawsky D, M Radike, K Jayasimhulu, T Cody (1988) Metabolism of benzo(a)pyrene by a dioxygenase system of the freshwater green alga Selenastrum capricomutum. Biochem Biophys Res Comm 152 540-544. 

FIGURE 2.18 Metabolism of benzo[a]pyrene by southern flounder. 

Polychaete worms belonging to the genera Nereis and Scolecolepides have extensive metabolic potential. Nereis virens is able to metabolize PCBs (McElroy and Means 1988) and a nnmber of PAHs (McElroy 1990), while N. diversicolor and Scolecolepides viridis are able to metabolize benzo[a]pyrene (Driscoll and McElroy 1996). It is worth noting that apart from excretion of the toxicant, polar, and mnch more water-soluble metabolites such as the glycosides formed from pyrene by Porcellio sp. (Larsen et al. 1998) may be mobile in the interstitial water of the sediment phase. 

Driscoll SK, AE McElroy (1996) Bioaccumulation and metabolism of benzo[a]pyrene in three species of polychaete worms. Environ Toxicol Chem 15 1401-1410. 

Little PJ, MO James, JB Pritchard, JR Bend (1984) Benzo(a)pyrene metabolism in hepatic microsomes from feral and 3-methylcholanthrene-treated southern flounder, Paralichthys lethostigma. J Environ Pathol Toxicol Oncol 5 309-320. 

Livingstone DR, SV Farrar (1984) Tissue and subcellular distribution of enzyme activities of mixed-function oxygenase and benzo[a]pyrene metabolism in the common mussel Mytilis edulis L. Sci Tot Environ 39 209-235. 

Michel XR, PM Cassand, DG Ribera, J-E Narbonne (1992) Metabolism and mutagenic activation of benzo(a)pyrene by subcellular fractions from mussel (Mytilus galloprovincialis) digestive gland and sea bass (Discenthrarcus labrax) liver. Comp Biochem Physiol 103C 43-51. 

Cremonesi P, EL Cavalieri, EG Rogan (1989) One-electron oxidation of 6-substituted benzo(a)pyrenes by manganic acetate. A model for metabolic activation. J Org Chem 54 3561-3570. 

The metabolism of pyrene and benzo[a]pyrene by C. elegans is increasingly complex. Pyrene is transformed by hydroxylation at the 1-, T and 6-, and 1- and 8- positions, and the bisphenols were glucosylated at the 6- and 8-positions the 1,6- and 1,8-pyrenequinones were also formed (Cerniglia et al. 1986). The same organism transformed benzo[fl]pyrene to the trany-7,8- and trans-... 

A cytochrome P450 has been purified from Saccharomyces cerevisiae that has benzo[a]pyrene hydroxylase activity (King et al. 1984), and metabolizes benzo[fl]pyrene to 3- and 9-hydroxybenzo[fl]pyrene and benzo[fl]pyrene-7,8-dihydrodiol (Wiseman and Woods 1979). The transformation of PAHs by Candida Upolytica produced predominantly monohydroxyl-ated products naphth-l-ol from naphthalene, 4-hydroxybiphenyl from biphenyl and 3- and 9-hydroxybenzo[fl]pyrene from benzo[fl]pyrene (Cerniglia and Crow 1981). The transformation of phenanthrene was demonstrated in a number of yeasts isolated from littoral sediments and of these, Trichosporumpenicillatum was the most active. In contrast, biotransformation of benz[fl]anthracene by Candida krusei and Rhodotorula minuta was much slower (MacGillivray and Shiaris 1993). 

Each plant tissue tends to have an obviously distinctive profile of flavonoids. The flavonoid content can reach about 0.5% in pollen, 10% in propolis, and about 6 mg/kg in honey. Havonoid aglycones appear to be present only in propolis and honey, while pollen contains flavanols in herosidic forms. The flavonoids in honey and propolis have been identified as flavanones and flavanones/flavanols (Campos et ah, 1990). The antimi-crobially active flavanone pinocembrine was foimd to be a major flavonoid in honey (Bogdanov, 1989). Amiot et ah (1989) studied two blossom and two honeydew Swiss honey samples and foimd that pinocembrine was the main flavonoid. Pinocembrine concentration varied between 2 and 3 mg/kg (Bogdanov, 1989). Berahia et ah (1993) analyzed sunflower honey samples and detected six flavone/flavols, four flavanone/ flavols, and pinocembrin, of which pinocembrin is the main flavonoid. The flavonoids in sunflower honey and propolis were characterized and assessed for their effects on hepatic drug-metabolizing enzymes and benzo [fl]pyrene-DNA adduct formation (Sabatier et ah, 1992 Siess et ah, 1996). 

Figure 4. The bay region dihydrodiol epoxide route of metabolism of benzo[a]pyrene.

Table I. Optical Purity of the Dihydrodiol Metabolites Formed in the Metabolism of Benzo[a]pyrene by Liver Microsomes from Untreated, Phenobarbital (PB)-, 3-Methylcholanthrene (3MC)-, and Polychlorinated Biphenyls (PCBs, Aroclor 1254)-Treated Rats...

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