Incorporation of esterified soybean isoflavones with antioxidant activity into low density lipoprotein

Meng, Qingguo; Lewis, Philip T.; Wähälä, Kristiina; Adlercreutz, Herman; Tikkanen, Matti J.

doi:10.1016/s1388-1981(99)00062-1

Cited by 76 publications

(40 citation statements)

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“…However, Tikkanen et al (19) found that isoflavones and their metabolites were present only in very small amounts in the LDL, and in the present study, no significant amounts of isoflavonoids were found associated with the LDL particles after isolation. Furthermore, although it was shown that esterified isoflavones can be incorporated into LDL ex vivo, resulting in greater oxidation resistance (40), it has not yet been shown that isoflavones can be esterified to LDL in vivo.…”

Section: Discussionmentioning

confidence: 99%

Isoflavone phytoestrogens consumed in soy decrease F2-isoprostane concentrations and increase resistance of low-density lipoprotein to oxidation in humans

Wiseman¹,

O'reilly²,

Adlercreutz³

et al. 2000

The American Journal of Clinical Nutrition

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335

177

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Background: Oxidative damage to lipids may be involved in the etiology of atherosclerosis, cardiovascular disease in general, and cancer. The soy isoflavone phytoestrogens, genistein and daidzein, and equol (a daidzein metabolite produced by intestinal microflora) are antioxidants in vitro; equol is a particularly good inhibitor of LDL oxidation and membrane lipid peroxidation. Objective: We sought to investigate the effects of a diet enriched with soy containing isoflavones on in vivo biomarkers of lipid peroxidation and resistance of LDL to oxidation, compared with a diet enriched with soy from which the isoflavones had been extracted. Design: A randomized, crossover design was used to compare diets enriched with soy that was low or high in isoflavones in 24 subjects. Plasma concentrations of an F 2 -isoprostane, 8-epiprostaglandin F 2␣ (8-epi-PGF 2␣ ), a biomarker of in vivo lipid peroxidation, and resistance of LDL to copper-ion-induced oxidation were determined. Results: Plasma concentrations of 8-epi-PGF 2␣ were significantly lower after the high-isoflavone dietary treatment than after the low-isoflavone dietary treatment (326 ± 32 and 405 ± 50 ng/L, respectively; P = 0.028) and the lag time for copperion-induced LDL oxidation was longer (48 ± 2.4 and 44 ± 1.9 min, respectively; P = 0.017). Lag time for oxidation of unfractionated plasma and plasma concentrations of malondialdehyde, LDL ␣-tocopherol, polyunsaturated fatty acids, and isoflavonoids did not differ significantly between dietary treatments. Conclusions: Consumption of soy containing naturally occurring amounts of isoflavone phytoestrogens reduced lipid peroxidation in vivo and increased the resistance of LDL to oxidation. This antioxidant action may be significant with regard to risk of atherosclerosis, cardiovascular disease in general, and cancer. Am J Clin Nutr 2000;72:395-400.

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Section: Discussionmentioning

confidence: 99%

Isoflavone phytoestrogens consumed in soy decrease F2-isoprostane concentrations and increase resistance of low-density lipoprotein to oxidation in humans

Wiseman¹,

O'reilly²,

Adlercreutz³

et al. 2000

The American Journal of Clinical Nutrition

Self Cite

335

177

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“…The concentrations of DAI in the different fractions obtained after lipoprotein separation of 2 ml plasma were measured by GC/MS using a stable isotopically labelled internal standard [3,4,[8][9][10][11][12][13] C]DAI. Total DAI was determined after extraction and enzymic hydrolysis with a mix of b-glucuronidase and sulfatase.…”

Section: Methodsmentioning

confidence: 99%

“…The separated lipoprotein fractions were equilibrated with 100 pmol [3,4,[8][9][10][11][12][13] C]DAI for 30 min at room temperature and diluted with five volumes of 0·5 M-triethylammonium sulfate (pH 5). Further details on sample clean-up, enzymic hydrolysis and derivatisation for GC/MS analysis are described by Rüfer et al (4) .…”

Section: Methodsmentioning

confidence: 99%

“…GC/MS conditions can be found in Rüfer et al (4) . The selected ion monitoring was applied to monitor two ions for each analyte, where the first was used for quantification and the second was used as confirmation of the presence of the analyte: m/z 398 and 383 for DAI as well as m/z 401 and 386 for [3,4,[8][9][10][11][12][13] C]DAI. DAI was quantified using ten calibration levels between 0 and 10 pmol.…”

Section: Methodsmentioning

confidence: 99%

“…[3,4,[8][9][10][11][12][13] C]DAI was obtained from Nigel Botting, University of St Andrews (St Andrews, UK). Enzymes and all other chemicals used were obtained from SigmaAldrich (Taufkirchen, Germany).…”

Section: Chemicalsmentioning

confidence: 99%

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Role of plasma lipoproteins in the transport of the soyabean isoflavones daidzein and daidzein-7-O-β-d-glucoside

et al. 2009

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Isoflavone intake is associated with various properties beneficial to human health which are related to their antioxidant activity, for example, to their ability to increase LDL oxidation resistance. However, the distribution of isoflavones among plasma lipoproteins has not yet been elucidated in vivo. Therefore, the objective of the present study was to investigate the association between daidzein (DAI) and lipoproteins in human plasma upon administration of the aglycone and glucoside form. Five men aged 22-30 years participated in a randomised, double-blind study in cross-over design. After ingestion of DAI and daidzein-7-O-b-D-glucoside (DG) (1 mg DAI aglycone equivalents/kg body weight) blood samples were drawn before isoflavone administration as well as 1, 2, 3, 4·5, 6, 8, 10, 12, 24 and 48 h post-dose. Concentrations of DAI in the different lipoprotein fractions (chylomicrons, VLDL, LDL, HDL) and in the non-lipoprotein fraction were analysed using isotope dilution capillary GC/MS. The lipoprotein fraction profiles were similar for all subjects and resembled those obtained for plasma in our previously published study. The lipoprotein distribution based on the area under the concentration -time profiles from 0 h to infinity in the different fractions were irrespective of the administered form: non-lipoprotein fraction (53 %) . LDL (20 %) . HDL (14 %) . VLDL (9·5 %) . chylomicrons (2·5 %). Of DAI present in plasma, 47 % was associated to lipoproteins. Concentrations in the different lipoprotein fractions as well as in the non-lipoprotein fraction were always higher after the ingestion of DG than of DAI. Taken together, these results demonstrate an association between isoflavones and plasma lipoproteins in vivo. Dietary isoflavones, a subclass of flavonoids, have been the focus of much of the recent interest in the nutritional benefits of soya foods (1) . The exact role that isoflavones play in the health-related effects of soya foods and their potential for adverse effects have been controversial and difficult to discern (2,3) . This may be in part due to the lack of basic knowledge regarding absorption, distribution, metabolism and excretion.In a recently published study, we investigated the difference in the bioavailability of the isoflavone daidzein (DAI) in the aglycone and glucoside form when administered as pure compounds (4) . In most subjects the plasma appearance and disappearance curves revealed a biphasic pattern with an early peak before the peak plasma concentration which has also been reported by other authors (5,6) . Possible reasons for this behaviour discussed so far are enterohepatic recycling and some small initial absorption in the upper gastrointestinal tract along with predominant absorption in the large intestine.A third explanation might be the absorption of isoflavones via a chylomicron-mediated mechanism and distribution of isoflavones bound to lipoproteins throughout the body. Several observations provide evidence for this hypothesis: It is known that water-insoluble compounds, for...

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Important Antioxidant Phytochemicals in Agricultural Food Products

2012

Analysis of Antioxidant‐Rich Phytochemicals

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Incorporation of esterified soybean isoflavones with antioxidant activity into low density lipoprotein

Cited by 76 publications

References 41 publications

Isoflavone phytoestrogens consumed in soy decrease F2-isoprostane concentrations and increase resistance of low-density lipoprotein to oxidation in humans

Isoflavone phytoestrogens consumed in soy decrease F2-isoprostane concentrations and increase resistance of low-density lipoprotein to oxidation in humans

Role of plasma lipoproteins in the transport of the soyabean isoflavones daidzein and daidzein-7-O-β-d-glucoside

Important Antioxidant Phytochemicals in Agricultural Food Products

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