The metabolism of cis- and trans-indane-1,2-diol

1. The metabolism of cis-indane-1,2-diol, trans-indane-1,2-diol, indene epoxide and 2-hydroxyindan-1-one in rats has been studied. The substances were administered to the animals by subcutaneous injection. 2. The urine of the dosed animals was examined for the presence of free and conjugated cis- and trans-dihydrodiols, and for each compound it was possible to isolate both cis and trans forms of indane-1,2-diol from the urine. 3. The urines were also examined by paper chromatography for ketones and two ketonic metabolites were detected in the urine of rats dosed separately with cis-indane-1,2-diol, trans-indane-1,2-diol, 2-hydroxyindan-1-one and indene epoxide. The ketones were provisionally identified as (1-oxoindan-2-yl glucosid)uronic acid and 1-oxoindan-2-yl sulphuric acid. 4. (1-Oxoindan-2-yl glucosid)uronic acid was isolated as the 2,4-dinitrophenylhydrazone from the urine of rats dosed separately with cis-indane-1,2-diol and trans-indane-1,2-diol. 5. Possible mechanisms for the interconversion of cis- and trans-indane-1,2-diol are discussed.     

Polymorphism of linoleic acid (cis-9, cis-12-octadecadienoic acid) and alpha-linolenic acid (cis-9, cis-12, cis-15-octadecatrienoic acid)

Crystallization and polymorphic properties of linoleic acid (cis-9, cis-12-Octadecadienoic acid) (LA) and alpha-linolenic acid (cis-9, cis-12, cis-15-Octadecatrienoic acid) (alpha-LNA) have been studied by optical microscopy, differential scanning calorimetry (DSC) and X-ray diffraction (XRD). The DSC analyses presented three polymorphs in LA, and two polymorphs in alpha-LNA. The XRD patterns of the higher- and lower-temperature forms in LA and alpha-LNA showed orthorhombic O'(//)+O-like and O'(//) subcell, which were similar to those of alpha- and gamma-forms of mono-unsaturated fatty acids, respectively. From the solvent crystallization of LA and alpha-LNA in acetonitrile, single crystals of the higher temperature polymorphs have been obtained. The crystal habits of truncated rhombic shape were also similar to those of alpha-forms of the mono-unsaturated fatty acids. The enthalpy and entropy values of fusion and dissolution of the alpha-forms of LA, alpha-LNA and oleic acid showed that the two values decreased with increasing number of the cis-double bond.     

Different mechanisms of cis-9,trans-11- and trans-10,cis-12- conjugated linoleic acid affecting lipid metabolism in 3T3-L1 cells

Conjugated linoleic acid (CLA) has been shown to reduce body fat mass in various experimental animals. It is valuable to identify its influence on enzymes involved in energy expenditure, apoptosis, fatty acid oxidation and lipolysis. We investigated isomer-specific effects of high dose, long treatment of CLA (75.4 μmol/L, 8 days) on protein and gene expression of these enzymes in cultured 3T3-L1 cells. Proteomics identified significant up- or down-regulation of 52 proteins by either CLA isomer. Protein and gene expression of uncoupling protein (UCP) 1, UCP3, perilipin and peroxisome proliferator-activated receptor (PPAR) α increased whereas UCP2 reduced for both CLA isomers. And eight-day treatment of trans-10,cis-12 CLA, but not cis-9,trans-11 CLA, significantly up-regulated protein and mRNA levels of PKA (P<.05), CPT-1 and TNF-α (P<.01). Compared to protein expression, both isomers did not significantly influence the mRNA expression of HSL, ATGL, ACO and leptin. In conclusion, high-dose, long treatment of cis-9,trans-11 CLA did not promote apoptosis, fatty acid oxidation and lipolysis in adipocytes, but may induce an increase in energy expenditure. trans-10,cis-12 CLA exhibited greater influence on lipid metabolism, stimulated adipocyte energy expenditure, apoptosis and fatty acid oxidation, but its effect on lipolysis was not obvious.     

Strain dependence of the metabolism of cis- and trans-isomers of 9-octadecenoic acid in perfused liver and cell-free preparation in rats

Hepatic metabolism of cis- and trans-9-octadecenoic acid was compared in various strains of rats and under different nutritional states. In Wistar rats triacylglycerol secretion was consistently higher in livers perfused with the cis isomer than with the trans isomer, while the difference was considerably attenuated in Sprague-Dawley rats. The difference in the hepatic triacylglycerol secretion disappeared when rats were fasted for 2 days. The rate of oxidation of trans fatty acid to ketone bodies was remarkably much higher than the cis isomer in Wistar but not in Sprague-Dawley rats. After fasting, the difference in the ketone body production disappeared in Wistar rats, whereas the oxidation rate was rather lower in the trans isomer than in the cis isomer in Sprague-Dawley rats. In isolated mitochondria, ketogenesis from trans-9-octadecenoic acid was markedly lower than that from the cis counterpart, irrespective of the nutritional states or strains of rats, and correlated well with the substrate specificity of carnitine acyltransferase. The molar concentration of malonyl-CoA to cause 50% inhibition of ketogenesis, the rate of peroxisomal beta-oxidation and the activity of acyl-CoA oxidase were all comparable, irrespective of the substrate sources. The Km value for acyl-CoA oxidase to the trans-acyl-CoA was 2-times higher than that of the cis counterpart in both strains of rats. Thus, peroxisomal as well as mitochondrial fatty acid oxidation systems apparently discriminated between the geometrical differences of the fatty acid substrate.     

NADPH-dependent reductive metabolism of cis-5 unsaturated fatty acids. A revised pathway for the beta-oxidation of oleic acid

Cis-5 double bond in a fatty acid or when encountered through the beta-oxidation of an odd-numbered double-bond unsaturated fatty acid presents as a metabolic block to the further beta-oxidation. Cis-5-fatty acyl-CoA cannot be beta-oxidized to cis-3-enoyl-CoA as suggested by the conventional pathway. Instead, this metabolic block can only be removed through an NADPH-dependent reduction of 5-enoyl-CoA, possibly mediated by a 5-enoyl-CoA reductase. In the case of oleic acid two cycles of beta-oxidation yield cis-5-tetradecenoyl-CoA. This intermediate is then reduced to tetradecanoyl-CoA, which is metabolized further via normal beta-oxidation cycles. The conventional pathway through cis-3-dodecenoyl-CoA does not operate in rat liver.     

The presence of cis-9,10-methylene hexadecanoic acid in Yersinia enterocolitica

The fatty acids of Yersinia enterocolitica were investigated by Abbas and Card. In their report, they stated that the major fatty acids were C16:0, C16:1, C17:0 and C18:1 and branched or cyclopropane side-chain fatty acids could not be detected. We, however, found a moderate amount of cyclopropane side-chain fatty acid. We could determine that this fatty acid was cis-9, 10-methylene hexadecanoic acid by gas-liquid chromatography, gas chromatography-mass spectrometry, silver-nitrate-treated TLC and PtO2 catalyzing hydrogenation method.     

Urinary metabolites of cis-9,10-methylene octadecanoic acid. cis-3,4-Methylene hexanedioic acid and related compounds.

cis-3,4-Methylene hexanedioic acid has been discovered in human urine. It has been isolated and identified by mass spectrometry and synthesis. The daily excretion in nine subjects on a free diet was 88 mumol/day (range, 32 to 144 mumol/day). cis-3,4-Methylene hexanedioic acid was given orally to a rat. About 90% of the dose was recovered unchanged in the urine within 24 h. Intragastric administration of cis-9,10-methylene [9,10-3H2]octadecanoic acid to rats gave four labeled urinary metabolites. The major one was cis-3,4-methylene hexanedioic acid, the others were 2,3-methylene pentanedioic acid and isomers of methylene heptanedioic acid and methylene octanedioic acid. Within 72 h, about 40% of the administered radioactivity could be recovered from the urine and another 40% from the carcass. About 20% of the recovered radioactivity was found to be water. Of the radioactivity administered to rats orally as cis-9,10-methylene [9,10-3H2]octadecanoic acid methyl ester, about 50% could be recovered from the lymph of the thoracic duct within 9 h. Intraperitoneal administration of cis-9,10-methylene octodecanoic acid methyl ester to rats gave the same metabolites. Of the given amount, 50 mol % could be recovered from the urine as cis-3,4-methylene hexanedioic acid and 19 mol % as homologues within 38 days.     

The effect of trans-10, cis-12 conjugated linoleic acid on gene expression profiles related to lipid metabolism in human intestinal-like Caco-2 cells

We conducted an in-depth investigation of the effects of conjugated linoleic acid (CLA) on the expression of key metabolic genes and genes of known importance in intestinal lipid metabolism using the Caco-2 cell model. Cells were treated with 80 μmol/L of linoleic acid (control), trans-10, cis-12 CLA or cis-9, trans-11 CLA. RNA was isolated from the cells, labelled and hybridized to the Affymetrix U133 2.0 Plus arrays (n = 3). Data and functional analysis were preformed using Bioconductor. Gene ontology analysis (GO) revealed a significant enrichment (P < 0.0001) for the GO term lipid metabolism with genes up-regulated by trans-10, cis-12 CLA. Trans-10, cis-12 CLA, but not cis-9, trans-11 CLA, altered the expression of a number of genes involved in lipid transport, fatty acid metabolism, lipolysis, β-oxidation, steroid metabolism, cholesterol biosynthesis, membrane lipid metabolism, gluconeogenesis and the citrate cycle. These observations warrant further investigation to understand their potential role in the metabolic syndrome.     

Microsomal ring-fission of cis- and trans-acenaphthene-1,2-diol

1. The ring-fission of cis- and trans-acenaphthene-1,2-diol by rat liver microsomes was studied. 2. 1,8-Naphthalic acid was detected and isolated after microsomal incubations of the diols. 3. The accompanying reduction of NAD(+) was followed spectrophotometrically. 4. The optimum pH for the microsomal reaction was 9.4 for the oxidation of the cis-diol and 9.8 for that of the trans-diol. 5. p-Chloromercuribenzoate and 2,4-dichlorophenol inhibited the reaction. 6. Possible mechanisms for the microsomal ring-fission, involving 1,8-naphthalic aldehyde, are discussed.     

Formation of cis-3-hexenal,trans-2-hexenal and cis-3-hexenol in macerated Thea sinensis leaves

Thea sinensis; Theaceae; tea; cis-3-hexenal: leaf aldehyde; leaf alcohol; linolenic acid; biosynthesis of leaf alcohol.Linolenic acid and cis-3-hexenal were found in macerated leaves of Thea sinensis and this aldehyde may be produced from linolenic acid by an enzyme contained in macerated leaves in the presence of oxygen. This aldehyde was easily isomerized to trans-2-hexenal, and was converted to cis-3-hexenol by alcohol dehydrogenase. During maceration of freshly picked tea leaves, the amounts of trans-2-hexenal quickly increased and were influenced by maceration time, heating, oxygen and the pH. But in unpicked tea leaves the occurrence of trans-2-hexenal is extremely doubtful.     

Trypanocidal structure-activity relationship for cis- and trans-methylpluviatolide

The trypanocidal activity of racemic mixtures of cis- and trans-methylpluviatolides was evaluated in vitro against trypomastigote forms of two strains of Trypanosoma cruzi, and in the enzymatic assay of T. cruzi gGAPDH. The cytotoxicity of the compounds was assessed by the MTT method using LLC-MK2 cells. The effect of the compounds on peroxide and NO production were also investigated. The mixture of the trans stereoisomers displayed trypanocidal activity (IC50 approximately 89.3 microM). Therefore, it was separated by chiral HPLC, furnishing the (+) and (-)-enantiomers. Only the (-)-enantiomer was active against the parasite (IC50 approximately 18.7 microM). Despite being inactive, the (+)-enantiomer acted as an antagonistic competitor. Trans-methylpluviatolide displayed low toxicity for LLC-MK2 cells, with an IC50 of 6.53 mM. Furthermore, methylpluviatolide neither inhibited gGAPDH activity nor hindered peroxide and NO production at the evaluated concentrations.     

Biological activity and conformational analysis of C20 and C14 epimers of CD-ring modified trans-decalin 1alpha,25-dihydroxyvitamin D analogs

In the context of our ongoing study of vitamin D structure-function relationships and in an attempt to obtain a better dissociation of their prodifferentiating (HL-60) and/or antiproliferative (MCF-7) activities and their calcemic activity, further 20-epi and 14-epi modifications were made to three trans-decalin CD-ring analogs of 1,25-dihydroxyvitamin D(3), the hormonally active metabolite of vitamin D(3), possessing a natural 20R side chain and featuring additional structural modifications in the seco-B-ring and in the A-ring. Following a previously observed trend and in agreement with the conformational analysis results, all three 20-epi derivatives show substantially lower biological activities, opposite to what is usually observed for analogs having the natural CD-ring. The 14-epi modification (cis-decalins) has little effect on the biological activity of the ynediene type and the saturated derivative, but results in an approximate 10-fold reduction in activity of the previtamin derivative. No better dissociation of the prodifferentiating and/or antiproliferative activities and the calcemic activity was achieved.     

Anti-ethylene Effects of cis-2-butene and cyclic olefins

The ability of butenes and cyclic olefins to induce an ethylene response or to counteract ethylene's action in etiolated pea seedlings was investigated. 1-Butene gave an ethylene-like response at 25 OOOμl/l. cis-Butene exhibited no ethylene-like response but appeared to overcome the action of 0.3 μl/l. ethylene at the same concentration. trans-Butene was without effect. 2,5-Norbornadiene competitively inhibited ethylene's action with a K_i of 170 μl/l. (computed as a gas). The K_i for norbornene was 360 μl/l. This value represents about one-half of the activity given by 2,5-norbornadiene. Other K_i values obtained were 488 μl/l. for 1,3-cyclohexadiene, 870 μl/l. for 1,3-cycloheptadiene, 1100 μl/l. for cyclopentene, 4700 μl/l. for 1,4-cyclohexadiene, and 6 ml/l. for cyclohexene. Cyclohexane and benzene were without efrect.