Accumulation of cis and trans chlordane by channel catfish during dietary exposure

Although chlordane is no longer in commercial use, residues of this complex mixture organochlorine insecticide in fish remain common. Accumulation of chlordane in the liver and muscle of the channel catfish (Ictalurus punctatus) was investigated through both multi-dose 28 day dietary exposures and a single-dose time course experiment in which both uptake and elimination were followed. Chlordane concentrations were also evaluated in channel catfish from an urban estuary. The cis isomer accumulated preferentially to the trans isomer in both liver and muscle tissues, and the cis to trans ratio generally exceeded the corresponding ratio in the spiked feed, suggesting a relative resistance to metabolism and/or excretion. The cis to trans ratio was three times greater in the wild fish than in the laboratory exposed fish. Although detected at low concentrations (relative to parent compounds) in the muscle and liver tissues of the wild fish, oxychlordane, a metabolite readily accumulated by mammals, was not detected in either tissue during any of the laboratory exposures. Elimination of the chlordane isomers from both liver and muscle was biphasic. In both tissues, the slow phase elimination constant (K_e) for trans-chlordane was 2–4 times that for cis-chlordane. Collectively, our results suggest that slower metabolism and/or excretion of the cis isomer relative to the trans isomer lead to the preferential accumulation of cis-chlordane in aquatic biota. Additionally, the presence of oxychlordane in channel catfish tissue may be due to direct exposure, rather than metabolism of parent compounds by the fish.     

Synthesis of σ receptor ligands with unsymmetrical spiro connection of the piperidine moiety

The symmetrically connected spiro[[2]benzopyran-1,4′-piperidines] 1 are highly potent and selective σ₁ receptor ligands. Changing the position of the spirocyclic nitrogen atom led to the unsymmetrically connected spiro[[2]benzopyran-1,3′-piperidines] 2 with a reduced distance between the aromatic system and the basic nitrogen atom. The synthesis of 2 was performed by halogen–metal exchange at the aryl bromide 3 followed by addition to the piperidone 5 and intramolecular transacetalization. The yield of 2a was considerably improved by transmetallation of the aryllithium intermediate 4a with CeCl₃ (4c). The cis and trans diastereomers cis-2 and trans-2 were separated and characterized by nuclear Overhauser effect. After removal of the benzyl group, the secondary amine 2b was alkylated with various alkyl and arylalkyl halides. The σ₁ and σ₂ receptor affinity of the spirocyclic piperidines 2 were determined with receptor binding studies. Compared with the spirocyclic piperidines 1, the unsymmetrically connected piperidines 2 show remarkably reduced σ₁ receptor affinities, whereas the selectivity over σ₂ and NMDA receptors was retained. A stereoselective interaction of the σ₁ receptor protein with the cis- or trans-configured spirocyclic compounds 2 was not observed. It was shown that alkyl residues at the N-atom can replace the lipophilic N-arylalkyl groups and interact with the primary hydrophobic binding site of the σ₁ receptor protein.     

Retinoids,Carotenoids, and Tocopherols in Breast Adipose Tissue and Serum of Benign Breast Disease and Breast Cancer Patients

Various retinoic acid (RA) isomers (all-trans, 13-cis, 11-cis, and 9-cis) as well as retinol, carotenoids, and tocopherol concentrations were determined in both serum and breast adipose tissue of 22 benign breast disease patients and 52 breast cancer patients categorized into 4 stages by malignancy. Serum RA isomers were analyzed by a newly developed sensitive method combining a high-performance liquid chromatography and a gas chromatography-mass spectrometry, and retinol, carotenoid, and tocopherol concentrations using a high-performance liquid chromatography system. The breast cancer patients showed significantly lower serum retinol, whereas significantly higher breast adipose tissue retinol concentration than those of benign breast disease patients. Although breast cancer patients showed significantly higher serum all-trans and 13-cis RA concentrations, 11-cis RA in breast adipose tissue was significantly lower in the breast cancer patients than those of benign breast disease patients and it was associated with the stage of malignancy. The current study indicates that the retinol and RA isomers in the target tissue of breast tumor patients are not reflecting their concentrations in circulation. The mechanisms of tissue specific uptake of RA isomers and their functions warrant further studies.     

Vitamin A5/X,a New Food to Lipid Hormone Concept for a Nutritional Ligand to Control RXR-Mediated Signaling

Vitamin A is a family of derivatives synthesized from carotenoids acquired from the diet and can be converted in animals to bioactive forms essential for life. Vitamin A1 (all-trans-retinol/ATROL) and provitamin A1 (all-trans-β,β-carotene/ATBC) are precursors of all-trans-retinoic acid acting as a ligand for the retinoic acid receptors. The contribution of ATROL and ATBC to formation of 9-cis-13,14-dihydroretinoic acid (9CDHRA), the only endogenous retinoid acting as retinoid X receptor (RXR) ligand, remains unknown. To address this point novel and already known retinoids and carotenoids were stereoselectively synthesized and administered in vitro to oligodendrocyte cell culture and supplemented in vivo (orally) to mice with a following high-performance liquid chromatography-mass spectrometry (HPLC-MS)/UV-Vis based metabolic profiling. In this study, we show that ATROL and ATBC are at best only weak and non-selective precursors of 9CDHRA. Instead, we identify 9-cis-13,14-dihydroretinol (9CDHROL) and 9-cis-13,14-dihydro-β,β-carotene (9CDHBC) as novel direct nutritional precursors of 9CDHRA, which are present endogenously in humans and the human food chain matrix. Furthermore, 9CDHROL displayed RXR-dependent promnemonic activity in working memory test similar to that reported for 9CDHRA. We also propose that the endogenous carotenoid 9-cis-β,β-carotene (9CBC) can act as weak, indirect precursor of 9CDHRA via hydrogenation to 9CDHBC and further metabolism to 9CDHROL and/or 9CDHRA. In summary, since classical vitamin A1 is not an efficient 9CDHRA precursor, we conclude that this group of molecules constitutes a new class of vitamin or a new independent member of the vitamin A family, named “Vitamin A5/X”.     

Effects of <Emphasis Type="Italic">trans</Emphasis>-10,<Emphasis Type="Italic">cis</Emphasis>-12 conjugated linoleic acid on cholesterol metabolism in hypercholesterolaemic hamsters

Background Conjugated linoleic acid (CLA) has received great attention in recent years because of its pleiotropic biological activities, but considerably fewer studies have been published addressing its role in serum lipids and atherosclerosis compared to other topics covered. Aims of the study The aim of the present study was to assess the effects of the trans-10,cis-12 isomer of CLA on cholesterolaemia and on several metabolic pathways involved in cholesterol metabolism in hamsters. Methods Animals were fed atherogenic diets supplemented with 0.5% linoleic acid, 0.5% trans-10,cis-12 CLA or 1.0% trans-10,cis-12 CLA, for 6 weeks. Serum lipoproteins were separated by FPLC. Cholesterol in serum and liver, as well as triacylglycerols and phospholipids in liver were assessed by spectrophotometry. 3-Hydroxy-3-methylglutaryl coenzyme A reductase (HMGCoAR), acyl-coenzyme A:cholesterol acyltransferase (ACAT) and cholesteryl ester hydrolase (CEH) activities were measured by radiometry, and LDL receptors were determined by Western blot. Results trans-10,cis-12 CLA feeding did not modify food intake nor final body weight. Although serum total cholesterol remained unchanged, when cholesterol fractions were analyzed a significant decrease in VLDL-cholesterol was observed in CLA-fed animals, without changes in HDL-cholesterol or LDL-cholesterol. trans-10,cis-12 CLA decreased cholesterol ester content and increased free cholesterol in liver. The activity of HMGCoAR was not modified. In contrast, ACAT activity was reduced by both CLA doses and CEH was increased by the high CLA dose. LDL receptors were significantly reduced by trans-10,cis-12 feeding when expressed as arbitrary units per mg of protein, however, the total receptor mass remained unchanged. Conclusions These results suggest that, under the present experimental conditions, trans-10,cis-12 CLA feeding reduces cholesterol esterification in liver and decreases the minority serum VLDL-cholesterol fraction, but it does not show a hypocholesterolaemic effect. A dose–response effect was not observed.     

In vivo andin vitro effect of phenoclor DP6 on drug metabolizing activity in mullet liver

Conclusions (IR)-cis-permethrin, decamethrin, and NRDC 168S are extremely lethal to salmon and lobster. The increase in lethality relative to that of permethrin follows qualitatively the patterns established in toxicity studies with insects: (IR)-cis isomers are more lethal than (IR)-trans, and the presence of an cyano group in the phenoxybenzyl moiety increases the lethality. The latter effect is very pronounced for lobsters.The octanol/water partition coefficient alone is not sufficient for predicting the lethality of pyrethroids to salmon or lobster.     

Quantitative determination of conjugated linoleic acid isomers by silver ion HPLC in ewe milk fat

The aim of this research was to validate a method for the quantification of conjugated linoleic acid (CLA) isomers in the fat of ewe's milk. The isomers in the form of methyl ester (FAME) are separated by silver ion high performance liquid chromatography (Ag⁺HPLC) and the quantification was based on the measurement of the integrated area under the 231 nm peaks, using external CLA reference standards. The response linearity is maintained in a wide range of concentrations and the quantification limit estimated was of 0.005 μg/injection for the cis-9,trans-11 and trans-10,cis-12 isomers. Referred to the samples this limit would be 0.008 mg/g of fat in the usual working conditions. In the precision assay an RSDr of 2.14% for the isomer cis-9,trans-11 was calculated and for the rest of the CLA isomers varied between 2.08 and 7.5%. The recovery assays were performed adding CLA cis-9,trans-11 triglyceride and the mean recovery was 96%. The method proposed allows the determination of the individual content of different CLA isomers using one single technique, HPLC and supposes saving time and resources.     

Effects of various traditional processing methods on the all-trans-β-carotene content of orange-fleshed sweet potato

The effects of traditional preparation methods and drying procedures on the provitamin A carotenoid content of orange-fleshed sweet potato (OFSP) roots was determined by a high-performance liquid chromatography (HPLC) method. All-trans-β-carotene was the major provitamin A carotenoid and the mean content of seven improved OFSP cultivars ranged from 108 to 315 μg/g dry matter. The retention of all-trans-β-carotene was 78% when OFSP were boiled in water for 20 min. When OFSP were steamed for 30 min the retention was 77%, whereas deep-frying OFSP roots for 10 min resulted in retention levels of 78%. Drying slices of OFSP roots at 57 °C in a forced-air oven for 10 h reduced the all-trans-β-carotene content by 12%. Solar drying and open-air sun drying OFSP slices to a moisture content of ⩽10% resulted in all-trans-β-carotene losses of 9% and 16%, respectively. The cis-isomer 13-cis-β-carotene was found in noticeable amounts in all processed samples, but not in any raw samples. The formation of 13-cis-β-carotene correlated with the original amount of all-trans-β-carotene found in the raw OFSP root. The high content of all-trans-β-carotene in the investigated improved OFSP varieties and the moderately low losses due to degradation and isomerization renders OFSP a suitable food source of provitamin A.     

Pyrimido[5,4-b]benzofuran and pyrimido[5,4-b]benzothiophene derivatives Ligands for α1-and 5HT1A-receptors

A number of 3-phenylpiperazinylethyl pyrimido[5,4-b]benzofuran-2,4-dione and pyrimido[5,4-b]benzothiophene-2,4-dione derivatives 5–15 were designed as bioisosters of the previously reported pyrimido[5,4-b]indole-2,4-diones and synthesized starting from the 3-amino-2-carboxybenzofuran and benzothiophene ethyl and methyl esters respectively. They were evaluated for their in vitroα₁-adrenoceptor and 5HT_1A-receptor affinities by radioligand receptor binding assays. All target compounds showed good to excellent affinities for the α₁-adrenoceptor with K_i values in the subnanomolar range. Some compounds were also good ligands for the 5HT_1A-receptor with K_i values in the nanomolar range. 3-[2-[4-(2-Methoxyphenyl)piperazin-1-yl]ethyl]-1-methyl pyrimido[5,4-b]benzothiophen-2,4-dione 15 was the most active derivative in displacing [³H]-8-OH-DPAT from rat hippocampal membranes. There is evidence suggesting that the N₁ methyl group of the tricyclic moiety of the title compounds is probably able to undergo a Van der Waals interaction at the 5HT_1A-receptor binding site but not at the α₁-adrenoceptor active site.     

Metabolism oftrans-nonachlor and related chlordane components in rat and man

The metabolic fate oftrans-nonachlor and heptachlor in rats was studiedin vivo andin vitro by using microsomal preparations of the liver. Duringin vivo studies the rate of excretion into urine and feces was monitored. The major metabolic products were collected from the feces and their chemical structures were determined by using various chromatographic and spectroscopic techniques. The immediate major metabolic product oftrans-nonachlor istrans-chlordane which is further converted to 1,2-dichlorochlordene and to oxychlordane. From the latter metabolite, two major stable products, 1-hydroxy-2-chlorochlordene and 1-hydroxy-2-chloro-2,3-epoxy-chlordene are formed. Another route of metabolism is a direct formation of chlordene chlorohydrin which acts as a precursor for 1,2-trans-dihydroxydihydrochlordene. The major metabolic products of heptachlor were heptachlor epoxide, 1-exo-hydroxyheptachlor epoxide and 1,2-dihydroxy-dihydrochlordene. As a result ofin vitro studies, it was established that the human liver has relatively little capability in convertingtrans-nonachlor totrans-chlordane, as compared to the rat liver similarly prepared. Since the livers from these two species showed almost identical degradation abilities fortrans-chlordane itself, the difference is apparently limited to this particular dechlorination step. The finding is consistent with the phenomenon thattrans-nonachlor accumulates in humans, but not in rats.     

Effect of 17β-oestradiol on transepithelial calcium transport in human intestinal-like Caco-2 cells and its interactions with 1,25−dihydroxycholecalciferol and 9-cis retinoic acid

Background Oestrogen therapy helps prevent bone loss in postmenopausal women and corrects a decline in Ca absorption efficiency at the onset of menopause. However, the mechanism by which 17β-oestradiol (17β-E₂) stimulates Ca absorption is unclear. Oestrogen may exert its effect indirectly via increasing 1,25-dihydroxycholeciferol (1,25 (OH)₂D₃) or its receptor, or act more directly on the intestines via the oestrogen receptor (OR). Since oestrogen also increases retinol levels, this may influence Ca absorption. Aim To investigate the effect of 17β-E₂ alone and in combination with 1,25 (OH)₂D₃ on intestinal Ca uptake and absorption in Caco-2 cells cultured under deplete- and replete-9-cis retinoic acid (9-cis RA) conditions. Methods Twenty-one day-old Caco-2 cell monolayers (n 9 wells per treatment) were exposed to 9-cis RA-deplete and -replete media containing dimethyl sulfoxide (control), 10 nM-1,25 (OH)₂D₃, 10 nM-17β-E₂, or 10 nM-1,25 (OH)₂D₃ plus 10 nM-17β-E₂, for 48 h. Results 1,25 (OH)₂D₃ stimulated Ca uptake, total Ca transport, calbindin D_9K and CaT1 mRNA levels, while 17β-E₂ and 9-cis RA had no effect on Ca absorption or uptake. Nor did they augment the stimulatory effect of 1,25 (OH)₂D₃. Conclusion These in vitro findings suggest that oestrogen does not have a direct effect on intestinal Ca absorption.     

Effect of processing conditions on the content of cis/trans carotene isomers as provitamin A carotenoids in Korean sweet potato varieties

The present investigation intends to evaluate the changes in the content of cis/trans carotene isomers as provitamin A carotenoids by steaming and roasting processes in the roots of four Korean sweet potato varieties viz. Shinzami, Younwhangmi, Chuwhangmi and Jinhongmi using a liquid chromatography with diode array detection and the negative ion atmospheric pressure chemical ionization mass spectrometric (LC-DAD-APCI/MS) method and UV spectral pattern library created from several reference data. Except Shinzami, the content of all trans β-carotenes was found to slightly decreased or remained constant when steamed or roasted. The content of cis α-/β-carotenes was potentially increased about 2-fold or greater when raw or steamed and the content was slightly decreased while roasted. In Chuwhangmi, the content of 13-cis α-carotene and all trans α-carotenes were rapidly increased when steamed and slightly decreased when roasted. Chuwhangmi exhibited 27.2?mg/100?g DW content of all trans β-carotenes when roasted and thus, it was considered as a relatively superior cultivar.     

Influence des acides gras polyinsaturés n-3 et des antioxydants alimentaires sur les acides gras de la viande et la lipoperoxydation chez le bovin en finition

This study aimed at analysing the impact, on beef lipids and fatty acids and on beef colour, of dietary lipid supplements provided by extruded linseeds (rich in n-3 polyunsaturated fatty acids, n-3 PUFA) alone or with extruded rapeseed (rich in n-6 and n-3 PUFA and in 18:1n-9) in association or not with dietary antioxidants in cull dairy cows in finition. Dietary linseeds increased significantly proportions of 18:3n-3 (+56% and +36% respectively), of total trans 18:1 (+66% and +105%); and of 9cis,11trans 18:2 (CLA) (+50% and +41%) in Longissimus thoracis and Semitendinosus muscles, 18:3n-3 and CLA being known to be beneficial for the human health. Antioxidant supplements (association of vitamin E with plant extracts rich in polyphenols, PERP) reinforced the stimulating effect of lipid supplements on proportions of 18:3 n-3, 18:1trans, and 9cis,11trans 18:2 in lipids of the two muscles. Dietary n-3 PUFA reduced the capacity of plasma to resist against lipoperoxidation (−11%) favouring the formation of peroxides such as conjugated dienes (× 1.75) and malonedialdehyde (MDA, ×2). Intensity of lipoperoxidation tended to increase in beef packaged under modified atmosphere rich in oxygen (O₂/CO₂: 70/30) of the linseed group (2.96 μg/g fresh tissue) when compared to that in the control group (2.19 μg/g, p = 0.1). Combined supply of vitamin E and PERP efficiently protected beef against lipoperoxidation, even in beef packaged under modified atmosphere rich in oxygen. Beef samples packaged under air from cows of the linseed group exhibited a more intense red colour than that of cows of the control group. In cows of the linseed group submitted to an emotional stress 2 hours before slaughtering, beef samples packaged under the air or the O₂-rich atmosphere had a red colour with a lower intensity that beef samples from cows of the linseed plus antioxidants group. In conclusion, feeding strategy for finishing cull cows combining lipid (from linseed rich in n-3 PUFA) and antioxidant (vitamin E + PERP) supplements improve the health value of beef fatty acids avoiding the major risks of beef lipoperoxidation and of alteration of beef colour whatever (i) the conditions of beef ageing and packaging (especially with O₂), (ii) the level of emotional stress of animals just before slaughtering.     

Synthesis and inhibition study of monoamine oxidase, indoleamine 2,3-dioxygenase and tryptophan 2,3-dioxygenase by 3,8-substituted 5H-indeno[1,2-c]pyridazin-5-one derivatives

Previous studies on 5H-indeno[1,2-c]pyridazin-5-one derivatives as inhibitors of MAO-B revealed that it was possible to increase the MAO-B inhibitory potency of 5H-indeno[1,2-c]pyridazin-5-ones by substituting the central heterocycle in the 3-position or C-8 with lipophilic groups which occupy the substrate cavity or the entrance of the binding site, respectively. Here, four new 5H-indeno[1,2-c]pyridazin-5-one derivatives containing lipophilic groups at both positions were synthesized and their inhibitory potency against human monoamine oxidase A and B were evaluated. Selectivity of these compounds against IDO and TDO, two enzymes sharing substrate similarity with MAO and involved in the serotonergic and kynurenine pathways was also studied. All compounds showed higher activity and selectivity against MAO-B, the most effective one being 3-methyl-8-meta-chlorobenzyloxy-5H-indeno[1,2-c]pyridazin-5-one (9a) which was shown to be a competitive inhibitor with a K_i value of 0.11 μM. Replacing the methyl group in the 3-position with a meta–CF₃–phenyl group (7a, 7b and 7c) abolished the inhibitory potency against MAO-B. Indeed, the substitution of the 5H-indeno[1,2-c]pyridazin-5-one core in the 3-position dramatically influences the MAO-inhibiting properties of these compounds. Molecular docking studies of 9a within MAO-B suggest that the 5H-indeno[1,2-c]pyridazin-5-one scaffold is well stabilized into the substrate cavity with the meta-chlorobenzyloxy side chain extending towards a rather hydrophobic pocket at the entrance cavity.     

Observations on the progress of chlordane contamination in humans by blood and sebum analysis

Chlordane residues were determined in human blood and sebum samples. The residue levels in both types of samples were remarkably increased in pest control operators and in the general population living in an area heavily contaminated with chlordane. The compound with the highest level among the residues in the blood of control subjects was oxychlordane followed bytrans- non- achlor andtrans- chlordane, while in the sebum, the highest levels found was that oftrans-chlordane followed bycis-chlordane andtrans-nonachlor. The sebum residue was similar to technical chlordane in its component pattern, but it largely originated from sources other than simple exogenous contamination. Thus, sebum might be a unique and available sample source for evaluating direct exposure to technical chlordane.A progressive state of contamination was observed in residents whose homes had been treated with chlordane.     

Oxygenated fatty acids isolated from wheat bran slurries

Oxygenated fatty acids are classified as secondary metabolites in wheat, produced by oxidation of free fatty acids (FFAs). Oxygenated fatty acids have significant impact on the organoleptic and sensory properties of food products and participate in regulation of defense and developmental processes in plants. The objective of this study was to identify oxygenated fatty acids from wheat flour slurries. Wheat bran/water slurries were incubated for 4?h and freeze dried. Total lipids were extracted in chloroform/methanol/water; and methylated and silylated FFAs were analyzed with gas chromatography/mass spectroscopy. Seven oxygenated fatty acids were identified, (A) 12,13-dihydroxy-9-octadecenoic acid, (B) 9-hydroxy-10,12-octadecadienoic acid, (C) 13-hydroxy-9cis,11trans-octadecadienoic acid, (D) 9,10,13-trihydroxy-11trans-octadecenoic acid, (E) 9,12,13-trihydroxy-10trans,15cis-octadecadienoic acid, (F) 10-oxo-13-hydroxy-11trans-octadecenoic acid and (G) 12-oxo-13-hydroxy-octadecanoic acid, in wheat bran slurries. Our results are important for whole wheat food applications since oxygenated fatty acids can result in bitter flavors in the final product.     

Vitamin A Derivatives as Treatment Options for Retinal Degenerative Diseases

The visual cycle is a sequential enzymatic reaction for vitamin A, all-trans-retinol, occurring in the outer layer of the human retina and is essential for the maintenance of vision. The central source of retinol is derived from dietary intake of both retinol and pro-vitamin A carotenoids. A series of enzymatic reactions, located in both the photoreceptor outer segment and the retinal pigment epithelium, transform retinol into the visual chromophore 11-cis-retinal, regenerating visual pigments. Retina specific proteins carry out the majority of the visual cycle, and any significant interruption in this sequence of reactions is capable of causing varying degrees of blindness. Among these important proteins are Lecithin:retinol acyltransferase (LRAT) and retinal pigment epithelium-specific 65-kDa protein (RPE65) known to be responsible for esterification of retinol to all-trans-retinyl esters and isomerization of these esters to 11-cis-retinal, respectively. Deleterious mutations in these genes are identified in human retinal diseases that cause blindness, such as Leber congenital amaurosis (LCA) and retinitis pigmentosa (RP). Herein, we discuss the pathology of 11-cis-retinal deficiency caused by these mutations in both animal disease models and human patients. We also review novel therapeutic strategies employing artificial visual chromophore 9-cis-retinoids which have been employed in clinical trials involving LCA patients.