Metabolites ether-soluble

C]PCNB metabolism was studied in vivo with 30-day-old peanut plants grown in nutrient solution that contained 17.6 ppm [I CjPCNB. Plant tissue was extracted with cold 80t methanol 48 hr after final exposure to PCNB. The extracts were made aqueous and partitioned against chloroform at pH 5.5 and against ethyl ether at pH 2. Water-soluble, chloroform-soluble, and ether-soluble metabolites were isolated by various chromatographic methods and identified by mass spectrometry and/or by synthesis. The details of these studies have been published previously (, X ... 

Figure 6. Ether-soluble metabolites isolated from the roots of peanut plants treated with FCNB. This represents 13.7% of the C isolated from the roots.

Two essentially different views of the metabolism of (2,4-dichloro-phenoxy) acetic acid have been presented. The first12 -124 was based on a 3tudy with bean stems, which converted 42% of (2,4-dichlorophenoxy)-acetic acid-l4C into acidic, water-soluble substances. Two ether-soluble metabolites were formed, and the same two metabolites could be recovered,... 

Quantitative differences in 2t4-D metabolism were also observed as a result of herbicide concentration and tissue age in soybean callus cultures (31). Unmetabolized 2(4-D constituted most of the extracted from three-wedc old callus tissue, and the concentration of free 2.4-D increased 32-fold in the tissue as external 2.4-D concentration was increased from 10 ° to 10 M (Figure 3). Aqueous (glycosides) and ether soluble metabolites (amino acid conjugates) were present in lower amounts, and increased slowly over the 10 ° to 10 M concentration range. In nine-week old callus cultures, ether soluble metabolites (2.4-D amino acid conjugates) were the major components of the tissue, and increased four-fold over a three-fold increase in 2.4-D concentration in the external medium (Figure 3). The concentration of 2.4-D remained low and relatively constant as it was converted to amino acid conjugates. Aqueous soluble metabolites formed a relatively minor component in nine-week old callus. 

Figure 3. Concentration of 2,4-D or 2,4-D metabolites found in various subfractions vs. total concentration in the ethanol extract of 3-week-old soybean root callus tissue (top) or 9-week-old soybean root callus tissue (bottom) following incubation for 48 h with various levels of C-2,4-D (1.8 x 10 ° to 1.1 x 10 M). The free 2,4-D was subtracted from the total ether-soluble metabolites (mostly amino acid conjugates). (Reproduced with permission from reference 31. Copyright 1978, American Society of Plant Physiologists.)...

The toxic effect depends both on lipid and blood solubility. I his will be illustrated with an example of anesthetic gases. The solubility of dinitrous oxide (N2O) in blood is very small therefore, it very quickly saturates in the blood, and its effect on the central nervous system is quick, but because N,0 is not highly lipid soluble, it does not cause deep anesthesia. Halothane and diethyl ether, in contrast, are very lipid soluble, and their solubility in the blood is also high. Thus, their saturation in the blood takes place slowly. For the same reason, the increase of tissue concentration is a slow process. On the other hand, the depression of the central nervous system may become deep, and may even cause death. During the elimination phase, the same processes occur in reverse order. N2O is rapidly eliminated whereas the elimination of halothane and diethyl ether is slow. In addition, only a small part of halothane and diethyl ether are eliminated via the lungs. They require first biotransformation and then elimination of the metabolites through the kidneys into the... 

The soluble metabolites excreted from animals dosed by injection were collected on AmberliteR XAD-4 resin, the resin eluted sequentially with diethyl ether, acetone, and methanol, and the solutes separated by thin-layer chromatography on silica gel and quantitated by liquid scintillation counting. 

Plant. Hiickelhoven et al. (1997) studied the metabolism of pyrene by suspended plant cell cultures of soybean, wheat, jimsonweed, and purple foxglove. Soluble metabolites were only detected in foxglove and wheat. Approximately 90% of pyrene was transformed in wheat. In foxglove, 1-hydroxypyrene methyl ether was identified as the main metabolite but in wheat, the metabolites were identified as conjugates of 1-hydroxypyrene. 

Four highly fluorinated ethers with low boiling points are currently used in anesthesia enflurane, isoflurane, sevoflumne, and desflurane (Figure 8.89). Des-flurane and sevoflurane are now the most used (sevoflurane is especially used in pediatrics). They exhibit the lowest blood-gas partition coefficients, the lowest ratio of toxic metabolites, and the lowest solubilities in lipids. These features limit the retention and, consequently, the metabolism is delayed (Table 8.2). 

Grass weed Animals. Rapidly oxidized by rat liver controller microsomal oxygenases via dechlorination, O-demethylation and side-chain oxidation Plants. Metabolism involves natural product conjugation of the chloroacetyl group and hydrolysis and sugar conjugation at the ether group. Final metabolites are polar, water-soluble, and nonvolatile... 

Polychlorinated diphenyl ethers (PCDE) are common impurities in chlorophenol formulations, which were earlier used as fungicides, slimicides, and as wood preservatives. PCDEs are structurally and by physical properties similar to polychlorinated biphenyls (PCB). They have low water solubility and are lipophilic. PCDEs are quite resistant to degradation and are persistent in the environment. In the aquatic environment, PCDEs bioaccumulate. These compounds are found in sediment, mussel, fish, bird, and seal. PCDEs show biomagnification potential, since levels of PCDEs increase in species at higher trophic levels. PCDEs are also detected in human tissue. Despite the persistence and bio accumulation, the significance of PCDEs as environmental contaminants is uncertain. The acute toxicity and Ah-receptor-me-diated (aryl hydrocarbon) activity of PCDEs is low compared to those of polychlorinated di-benzo-p-dioxins (PCDD) and dibenzofurans (PCDF). Due to structural similarity to thyroid hormone, PCDEs could bind to thyroid hormone receptor and alter thyroid function. Furthermore, PCDEs might be metabolized to toxic metabolites. In the environment, it is possible that photolysis converts PCDEs to toxic PCDDs and PCDFs. 

The hydrolysis of steroid hydrogen sulphates, important to biochemists in view of the excretion of many steroid hormone metabolites as water soluble salts of hydrogen sulphates, has been studied in some detail [20,21]. It had been known for some years that ether extraction of the steroid hydrogen sulphate from acidified solutions is accompanied by hydrolysis of the sulphate in the ether phase, with liberation of the steroid alcohol. This hydrolysis was shown to follow first-order kinetics, but to be dependent in a remarkable way on the solvent. Ethers are the most effective solvents, followed by others of low polarity including benzene, esters and ketones, while water and alcohols have a strong retarding effect on hydrolysis. Neither acids nor bases produce significant catalysis, and the presence of did not result in incorporation of isotopic... 

Crystals From di] at) NaOH. Dec above 300" without melting. Absorption spectrum L. F. Cavalieri el al. J. Am. Chem. Soc. 70, 3875 (1948), Soluble in dil caustic, in di] acids. Practically insol in water, alcohol, ether. use Purine anti metabolite,... 

Solvents commonly used in normal phase chromatography are aliphatic hydrocarbons, such as hexane and heptane, halogenated hydrocarbons (e.g., chloroform and dichloromethane), and oxygenated solvents such as diethyl ether, ethyl acetate, and butyl acetate. More polar mobile phase additives such as isopropanol, acetone, and methanol are frequently used see Table 2). The technique is particularly suited to analytes that are very hydrophobic, e.g., fat-soluble vitamins such as tocopherols (6J and other hydrocarbon-rich metabolites that exhibit poor solubility in the water-miscible solvents employed in other separation modes. In addition, since the geometry of the polar adsorbent surface is fixed, the technique is useful for the separation of positional isomers the proximity of functional groups to the adsorbent surface, and hence the strength of interaction, may well differ between isomers. 

C15H20O2, Mr 232.32, colorless crystals, mp. 82 °C, bp. 275 °C, [a] 3 +197° (CHCI3), almost insoluble in water, soluble in alcohol and ether. The name of this tricyclic sesquiterpene lactone is derived from the Asteraceae ]nula helenium originally indigenous to Central Asia. H. was isolated for the first time from the essential oil of the roots (Inula oil). H. is also an older synonym for helenalin as well as the name for a metabolite from Penicillium funiculosum (ribonucleoprotein). Because of its a-methylene-y-lactone structure H. is a contact allergen. 

To obtain more information on the nature of the degradation products of the estrogens,. Jellinck (1959) incubated human and rat liver slices as well as mushroom tyrosinase with estrone-/ff-C. The results showed that liver and phenol oxidase of mushroom have a marked ability for converting estrone into water-soluble, ether-insoluble metabolites. The formation of these products was almost completely abolished by cyanide. From an investigation of the estrone degradation products, Jellinck (1959) reached... 

Petroleum ether vapor plasma polymerization was used for the surface modification of the chitosan membranes to control their permeation rate of water-soluble drugs and metabolites (Wang et al. 2001). This treatment also significantly improved the mechanical properties of the membrane. 

Since vitamin D and its metabolites are fat-soluble sterols, partition into organic solvents provides significant purification by removal of water-soluble contaminants. Solvent systems for extraction fall into two basic categories (see Table 4) [1] total lipid extraction, for example, methanol-chloroform-water (2 1 0 8) (83) or ethanol-water (9 1) (84), and [2] selective lipid extraction, for example, ether, ethylacet-ate-cyclohexane (1 1), hexane, dichloromethane, or hexane-isopropanol (1 2). 

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