Reaction of cholesterol 5,6‐epoxides with simulated gastric juice

Maerker, G.; Nungesser, Edwin; Bunick, Frank J.

doi:10.1007/bf02536218

Cited by 33 publications

(15 citation statements)

References 32 publications

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“…3 gas chromatograph coupled to an SPB-1 fused silica capillary column (60 m×0. 25 Helium was used as the carrier gas, the total run time being 42.5 min. The gas chromatograph was operated in the constant ‰ow mode, with the ‰ow rate set to 1.5 ml He W min.…”

Section: Animals and Permanent Lymph Duct Cannulationmentioning

confidence: 99%

“…Therefore, a-and b-epoxycholesterol and cholestanetriol found in the basal lymph might have been derived from the diet. Cholestanetriol might have been derived from a-and b-epoxycholesterols, since Maerker et al 25) have shown that cholestanetriol was easily formed when epoxycholesterols were incubated with gastric juice. Alternatively, we cannot neglect the possibility that the oxysterols found in the basal lymph might have been produced during the preparation.…”

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confidence: 99%

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Lymphatic Transport of Dietary Cholesterol Oxidation Products, Cholesterol and Triacylglycerols in Rats

Tomoyori

Carvajal

Nakayama

et al. 2002

Bioscience, Biotechnology, and Biochemistry

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Rats were fed on a diet containing 0.5% cholesterol oxidation products (oxysterols) or 0.5% cholesterol for 30 min, and their lymph was collected for 7 h. The amount of each of the individual oxysterols absorbed in the lymph depended on the ingested amounts, but the recovery was the highest for 5alpha,6alpha-epoxycholesterol (10.5%), this being followed by 7-ketocholesterol (5.8%), cholestanetriol (5.2%), 7beta-hydroxycholesterol (4.8%), 7alpha-hydroxycholesterol (3.4%), 5beta,6beta-epoxycholesterol (2.2%), and 25-hydroxycholesterol (1.8%). A diet enriched with oxysterol, but not cholesterol, resulted in increased transport of triacylglycerols in the lymph. These results suggest that the absorption rate of oxysterols depends on the type, and indicate that the effect of dietary oxysterols on the lymphatic transport of triacylglycerols differs from that of dietary cholesterol. It therefore remains to be determined which oxysterol was responsible for the triacyglycerol transport.

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Section: Animals and Permanent Lymph Duct Cannulationmentioning

confidence: 99%

mentioning

confidence: 99%

Lymphatic Transport of Dietary Cholesterol Oxidation Products, Cholesterol and Triacylglycerols in Rats

Tomoyori

Carvajal

Nakayama

et al. 2002

Bioscience, Biotechnology, and Biochemistry

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“…Hydrolysis of epoxy compounds to render the corresponding diols may also occur before absorption, under the acidic conditions in gastric media (Maerker, 1988;Piazza et al 2003;Giuffrida et al 2004). This is of great importance because monoepoxy compounds have been recently found to be one of the major oxidized groups formed at frying temperatures (Velasco et al 2004a(Velasco et al , 2004b, accounting for about 25% of total oxidized fatty acyl groups in real used frying oils at the limit of rejection.…”

Section: Dietary Oxidized Lipids Under Gastric Conditionsmentioning

confidence: 99%

Changes and Effects of Dietary Oxidized Lipids in the Gastrointestinal Tract

Márquez‐Ruiz¹,

Garcı́a-Martı́nez²,

Holgado³

2008

Lipid�Insights

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This paper is focused on the present state-of-the art of modifi cations and effects of dietary oxidized lipids during their transit along the gastrointestinal tract. A survey of the literature reporting changes and effects of oxidized lipids before absorption, fi rst in the stomach and then during enzymatic lipolysis in the small intestine, are addressed. Also, the fate of non-absorbed compounds and their potential implications at the colorectal level are discussed. Among the results found, it is shown that acidic gastric conditions and the infl uence of other dietary components may lead to either further oxidation or antioxidative effects in the stomach. Also, changes in oxidized functions, especially of hydroperoxy and epoxy groups, seem likely to occur. Enzymatic hydrolysis by pancreatic lipase is not effective for triacylglycerol polymers, and hence they can be found as non-absorbed oxidized lipids in the large intestine. Interactions of oxidized lipids with cholesterol absorption in the small intestine and with microfl ora metabolism have been also observed.

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“…Although present in the diet, the epoxycholesterols were not detected at a significant level in the plasma. It is well known that the epoxy-derivatives can be transformed in cholestanetriol in acidic fluid such as stomach secretion (Maerker et al 1988;Schroepfer, 2000). This synthesis can also be carried out by an hepatic epoxide hydrolase (Watabe et al 1980;Sevanian & McLeod, 1986).…”

Section: Sterols In Food Plasma and Heartmentioning

confidence: 99%

Effects of dietary oxysterols on coronary arteries in hyperlipidaemic hamsters

Meynier

Lherminier

Demaison-Meloche

et al. 2002

British Journal of Nutrition

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The aim of this study was to evaluate the effect of dietary oxysterols on coronary atherosclerosis and vasospasm. Golden Syrian hamsters were fed three diets with different lipid contents for 3 months: (1) a normolipidaemic diet containing 25 g corn oil -fish oil (4:1, w/w)/kg (group Low L); (2) a hyperlipidaemic diet composed of the normolipidaemic diet supplemented with 150 g lard þ 30 g cholesterol/kg (group High L); (3) a third diet, similar to the hyperlipidaemic diet, in which 4 g cholesterol/kg was replaced by a mixture of oxysterols (group High L þ OS). The oxysterol mixture contained (g/kg): 5,6a-epoxycholesterol 211, 5,6b-epoxycholesterol 179, 7a-hydroxycholesterol 67, 7b-hydroxycholesterol (7bOH) 185, 7-ketocholesterol (7 K) 235; and trace amounts of 7-hydroperoxycholesterols (approximately 30 g/kg). Atherosclerosis was evaluated by measuring myocardial Ca, oxysterols and acyl-CoA cholesterol acyl transferase (ACAT) activity; furthermore, coronary reactivity to sodium nitroprusside ð5 £ 10 26 mÞ was measured and the morphology of coronary arteries was visualized by transmission electron microscopy. Coronary spasm was determined by evaluating reactivity to serotonin ð5 £ 10 26 mÞ. Feeding the high-lipid diet (group High L) increased the plasma level of 7bOH, 7 K and cholestanetriol. The presence of oxysterols in the diet (group High L þ OS) further increased the concentrations of 7bOH and 7 K in the plasma. However, as evidenced by myocardial Ca, ACAT activity and coronary reactivity to sodium nitroprusside, severe atherosclerosis did not develop during the 3-month diet. 7 K was increased in myocardial lipids of groups High L and High L þ OS. Electron microscopy did not show the development of atherosclerosis in group High L, whereas vascular wall thickening, endothelial damage and smooth muscle cell proliferation and migration occurred when oxysterols were present in the food. Serotonin ð5 £ 10 26 mÞ induced exacerbated coronary vasoconstriction in group High L that was completely reversed by dietary oxysterols. In conclusion, dietary oxysterols exhibit antispasmodic properties, but they cannot be used as agents against excess dietary lipid-induced coronary spasm because of their atherogenic properties.

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Reaction of cholesterol 5,6‐epoxides with simulated gastric juice

Cited by 33 publications

References 32 publications

Lymphatic Transport of Dietary Cholesterol Oxidation Products, Cholesterol and Triacylglycerols in Rats

Lymphatic Transport of Dietary Cholesterol Oxidation Products, Cholesterol and Triacylglycerols in Rats

Changes and Effects of Dietary Oxidized Lipids in the Gastrointestinal Tract

Effects of dietary oxysterols on coronary arteries in hyperlipidaemic hamsters

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