Sulfation glucuronidation and

Absorption of (-)-epicatechin from chocolate has been studied by different authors [104-106]. Baba et al [104] found maximum levels of total EC metabolites in plasma after 2 h of chocolate or cocoa intake. Sulfate, glucuronide and sulfoglucuronide conjugates of non-methylated EC were the main metabolites present rather than methylated forms. In urine samples, excretion of total EC metabolites within 24 h was about 30% of total EC intake after chocolate and 25 % after cocoa consumption. 

K. L. R. Integration of hepatic drug transporters and phase II metabolizing enzymes Mechanisms of hepatic excretion of sulfate, glucuronide, and glutathione metabolites. Eur. J. Pharm. Sci. 27, 447-486, 2006. 

Figure 4-1. Metabolism of acetaminophen to harmless conjugates or to toxic metabolites. Acetaminophen glucuronide, acetaminophen sulfate, and the mercapturate conjugate of acetaminophen are all nontoxic phase II conjugates. Ac is the toxic, reactive phase I metabolite. Transformation to the reactive metabolite occurs if hepatic stores of sulfate, glucuronide, and glutathione are depleted or overwhelmed or if phase I enzymes have been induced.

DHBs after absorption distribute rapidly and widely among tissues but bio accumulation is low (121). They are metabolized to their respective benzoquinone and then detoxified by conjugation and excreted in the urine mainly as conjugates. Some deconjugations may occur in the urine. Resorcinol is also excreted in the urine in a free and conjugated state, essentially glucuronide and sulfate. 

Only the small amounts of T and T that are free in the circulation can be metabolized. The main route is deiodination of T to T and i-T, and from these to other inactive thyronines (21). Most of the Hberated iodide is reabsorbed in the kidney. Another route is the formation of glucuronide and sulfate conjugates at the 4 -OH in the Hver. These are then secreted in the bile and excreted in the feces as free phenols after hydrolysis in the lower gut. 

About 97% of po dose is absorbed from the GI tract. The dmg undergoes extensive first-pass hepatic metaboHsm and only 12% of the po dose is bioavailable. More than 95% is protein bound and peak plasma concentrations are achieved in 2—3 h. Therapeutic plasma concentrations are 0.064—1.044 lg/mL. The dmg is metabolized in the Hver to 5-hyroxypropafenone, which has some antiarrhythmic activity, and to inactive hydroxymethoxy propafenone, glucuronides, and sulfate conjugates. Less than 1% of the po dose is excreted by the kidney unchanged. The elimination half-life is 2—12 h (32). 

The duration of action of acetaminophen is limited by the formation of water-soluble derivatives of the phenol (glucuronide and sulfate) that are then excreted via the kidney. Protection i)f the phenol as an ether inhibits such inactivation without diminishing biologic activity. Acetylation of p-ethoxyaniline iffords the widely used peripheral analgesic, phenacetin (25). ... 

MRP1 (ABCC1) Glucuronides and sulfate conjugates of steroid hormones and bile salts, colchicine, doxorubicin, daunorubicin, epirubicin, folate, irinotecan, methotrexate, pacitaxel, vinblastine, vincristine, and others... 

In a study of the metabolism of methyl parathion in intact and subcellular fractions of isolated rat hepatocytes, a high performance liquid chromatography (HPLC) method has been developed that separates and quantitates methyl parathion and six of its hepatic biotransformation products (Anderson et al. 1992). The six biotransformation products identified are methyl paraoxon, desmethyl parathion, desmethyl paraoxon, 4-nitrophenol, />nitrophenyl glucuronide, and /wiitrophenyl sulfate. This method is not an EPA or other standardized method, and thus it has not been included in Table 7-1. 

Asai, A. and Miyazawa, T., Occurrence of administered curcuminoid as glucuronide and glucuronide/sulfate conjugates in rat plasma, Life Sci., 67, 2785, 2000. 

Cerniglia CE, JP Freeman, RK Mitchum (1982b) Glucuronide and sulfate conjugation in the fungal metabolism of aromatic hydrocarbons. Appl Environ Microbiol 43 1070-1075. 

After exerting their action in the organism, natural and synthetic hormones are catabolized in the liver by conjugation to glucuronide and/or sulfate moieties, forming more polar conjugated forms which are excreted via urine. This is the main route of hormone excretion in humans and pigs. A fraction of hormones is also excreted in a free form via feces in animals such as sheep and cattle this is the main route for hormone excretion (Table 3) [66, 67],... 

Stehly, G.R. and W.L. Hayton. 1988. Detection of pentachlorophenol and its glucuronide and sulfate conjugates in fish bile and exposure water. Jour. Environ. Sci. Health B23 355-366. 

After 72 h, bile contained 25% of the total radioactivity major BaP metabolites were glucuronides (54%), sulfates (12%), and unmetabolized BaP(14%). The potentially genotoxic metabolite BaP-7,8-dihydrodiol and its glucuronide represented 0.7 and 2.0%, respectively, of the bile radioactivity BaP and chrysene were most efficient in elevating EROD activities, cytochrome P-4501 A protein levels, and total cytochrome P-450 content 1-14 days postinjection. Less pronounced increases were caused by fluoranthene and pyrene B[gh/]PER did not affect these parameters... 

The concept of microbial models of mammalian metabolism was elaborated by Smith and Rosazza for just such a purpose (27-32). In principle, this concept recognizes the fact that microorganisms catalyze the same types of metabolic reactions as do mammals (32), and they accomplish these by using essentially the same type of enzymes (29). Useful biotransformation reactions common to microbial and mammalian systems include all of the known Phase I and Phase II metabolic reactions implied, including aromatic hydroxylation (accompanied by the NIH shift), N- and O-dealkylations, and glucuronide and sulfate conjugations of phenol to name but a few (27-34). All of these reactions have value in studies with the alkaloids. 

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