The Biogenesis of Conjugation and Detoxication Products

Williams, R. T.

doi:10.1016/b978-0-08-002925-2.50015-2

Cited by 13 publications

(10 citation statements)

References 151 publications

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“…To our knowledge there have been no reports of the biogenesis of BPA diglucuronide. Glucuronidation of phenols by animals is usually seen as a detoxification that both deactivates (for example, 17‐β estradiol) and increases solubility and allows ready urinary excretion [25]. Glucuronide conjugation of foreign compounds and unwanted metabolites is widespread in the animal kingdom, with only insects utilizing glucoside conjugation for phenol detoxification [25].…”

Section: Discussionmentioning

confidence: 99%

“…Glucuronide conjugation of foreign compounds and unwanted metabolites is widespread in the animal kingdom, with only insects utilizing glucoside conjugation for phenol detoxification [25]. On the other hand, in plants glucoside formation from foreign compounds has been known since 1938, and the widespread formation of phenolic glucosides has been reported [25]. The metabolism of BPA by animals and plants is apparently consistent with these general observations, and the syntheses and estrogenicity studies reported will further facilitate study of the environmental and health consequences of its release.…”

Section: Discussionmentioning

confidence: 99%

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Synthesis and estrogenic activity of bisphenol A mono- and di-β-D-glucopyranosides, plant metabolites of bisphenol A

Morohoshi

Shiraishi

Oshima

et al. 2003

Environmental Toxicology and Chemistry

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The syntheses and characterization of bisphenol A mono- and di-beta-D-glucopyranosides were undertaken to confirm that these compounds are major plant metabolities of bisphenol A (BPA) and to allow an assessment of their estrogenicity. Synthesis involved the glucosidation of unprotected BPA with glucose penta-acetate with phosphorus oxychloride as catalyst. The estrogenic activity of BPA and its mono- and di-beta-D-glucopyranosides were measured with an enzyme-linked immunosorbent assay (ELISA)-based estrogen receptor competitive binding assay and with a yeast two-hybrid assay adapted to a chemiluminescent reporter gene (for beta-galactosidase). Both methods showed that the estrogenicity of BPA was eliminated by formation of the di-glucoside, but whereas the ELISA-based method indicated that reduced activity remained in the monoglucoside, the yeast two-hybrid method showed the monoglucoside to be inactive. Presumably these results reflect the more complex interactions of test compound and cellular components required to demonstrate estrogenicity in the yeast two-hybrid assay. As these processes parallel those in mammalian cells, the yeast two-hybrid method is likely to be the more realistic assay. The uptake and metabolism of BPA by plants offers the possibility of phytoremediation of contaminated water, but also provides an additional route for the compound to enter the human food chain.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Synthesis and estrogenic activity of bisphenol A mono- and di-β-D-glucopyranosides, plant metabolites of bisphenol A

Morohoshi

Shiraishi

Oshima

et al. 2003

Environmental Toxicology and Chemistry

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“…Recent studies on BPA metabolism in plant cells of various species reported the occurrence of BPA in free and glycosylated forms, highly polar products and nonextractable (bound) residues (Hamada et al 2002;Nakajima et al 2002Nakajima et al , 2004Schmidt and Schuphan 2002). In particular, metabolic BPA products can be considered as detoxified forms (Schmidt and Schuphan 2002;Williams 1967). On these basis, we can assume that tomato was not only able to accumulate large amounts of BPA in the roots, but also to translocate BPA to shoots, and that a complete biotransformation and detoxification do not occur either in the roots or in the shoots.…”

Section: Residual Bpa Concentration In Nutrient Solutions Roots and mentioning

confidence: 99%

Phytotoxic, clastogenic and bioaccumulation effects of the environmental endocrine disruptor bisphenol A in various crops grown hydroponically

Ferrara

Loffredo

Senesi

2005

Planta

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The effects of the endocrine disruptor bisphenol A (BPA) at concentrations of 10 and 50 mg l(-1) were evaluated on the germination and morphology, micronuclei (MN) content in root tip cells and BPA bioaccumulation of hydroponic seedlings of broad bean (Vicia faba L.), tomato (Lycopersicon esculentum Mill.), durum wheat (Triticum durum Desf.) and lettuce (Lactuca sativa L.) after 6 and 21 days of growth. In general, BPA at any dose used did not inhibit germination and early growth (6 days) of seedlings of the species examined, with the exception of primary root length of tomato which decreased at the higher BPA dose. In contrast, an evident phytotoxicity was induced by BPA in all species after 21 days of growth with evident morphological anomalies and significant reductions of the lengths and fresh and dry weights of shoots and roots of seedlings. With respect to the nutrient medium without seedlings, BPA concentration decreased markedly during the growth period in the presence of broad bean and tomato seedlings, and limitedly in the presence of durum wheat and, especially, lettuce. Further, the presence of BPA measured in roots and shoots of broad bean and tomato after 21-day growth indicated that bioaccumulation of BPA had occurred. The number of MN in broad bean and durum wheat root tip cells increased markedly by treatment with BPA at both concentrations, thus suggesting a potential clastogenic activity of BPA in these species.

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“…In most cases, this sequential process is initiated by phase-I enzymes like cytochromes P450 (P450) which introduce a functional group into the molecule. The phase-I1 enzymes can then add a hydrophilic molecule such as water (by epoxide hydrolase) or glutathione (by glutathione-S-transferases; Williams, 1967 …”

mentioning

confidence: 99%

Engineered yeast cells as model to study coupling between human xenobiotic metabolizing enzymes

Gautier

Urban

Beaune

et al. 1993

European Journal of Biochemistry

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Human microsomal epoxide hydrolase and cytochrome P450 (P450) 1Al were coexpressed in Saccharomyces cerevisiae from expression cassettes integrated respectively into the host chromosomal DNA and on a multicopy plasmid in a strain already overexpressing yeast NADPH-cytochrome P450 reductase (P450 reductase). A styrene-oxide-hydrolase activity (2 nmol . min-. mg microsomal protein-') and a 7-ethoxyresorufin-0-deethylase activity (320 pmol . min-' . mg microsomal protein-') characteristic respectively of microsomal epoxide hydrolase and P450 1Al were detected. The conversion of benzo[a]pyrene (B[a]P) to B[a]P-7,8-dihydrodioI both in microsomal preparations and in growing yeast cells was observed, demonstrating an efficient coupling between the two human enzymes. Kinetic analysis indicated that the B[a]P-7,8-oxide produced by the P450-1Al-dependent reaction does not accumulate before hydrolysis by microsomal epoxide hydrolase. This system was also used as a control to evaluate the coupling efficiency of a mixture of microsomes or of yeast cells containing separately the individual enzymes (i.e., human P450 1Al and microsomal epoxide hydrolase). B[a]P-7,8-oxide was well converted to the corresponding dihydrodiol with a mixture of microsomes. In contrast, when the same experiment was repeated with a mixture of cells expressing independently the two activities, dihydrodiol formation was not observed. Coexpression of human phase I and phase 11 enzymes in a single yeast cell and microsome mixture thus appear to be complementary tools for the simulation of human-drug-metabolism or carcinogen-metabolism pathways.Numerous endogenous and foreign lipophilic compounds are metabolized in organisms through multistep metabolic pathways, converting them to more polar molecules which can be more easily excreted. In most cases, this sequential process is initiated by phase-I enzymes like cytochromes P450 (P450) which introduce a functional group into the molecule. The phase-I1 enzymes can then add a hydrophilic molecule such as water (by epoxide hydrolase) or glutathione (by glutathione-S-transferases; Williams, 1967

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The Biogenesis of Conjugation and Detoxication Products

Cited by 13 publications

References 151 publications

Synthesis and estrogenic activity of bisphenol A mono- and di-β-D-glucopyranosides, plant metabolites of bisphenol A

Synthesis and estrogenic activity of bisphenol A mono- and di-β-D-glucopyranosides, plant metabolites of bisphenol A

Phytotoxic, clastogenic and bioaccumulation effects of the environmental endocrine disruptor bisphenol A in various crops grown hydroponically

Engineered yeast cells as model to study coupling between human xenobiotic metabolizing enzymes

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