Consumption of flavonoids in onions and black tea: lack of effect on F2-isoprostanes and autoantibodies to oxidized LDL in healthy humans

O'reilly, James; Mallet, Anthony I.; Mcanlis, Gareth T.; Young, Ian S.; Halliwell, Barry; Sanders, Tom; Wiseman, Helen

doi:10.1093/ajcn/73.6.1040

Cited by 118 publications

(61 citation statements)

References 40 publications

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“…OH and MDA were low (Table 2). Scavenging activity of A. sativum leaf extract was also high (90.36%) which is in agreement with results from a number of previous studies [22][23][24] that investigated garlic and onion antioxidant and pharmacological activities. Scavenging activity in bulbs of investigated Allium was also high but lower than that in leaves.…”

Section: Resultssupporting

confidence: 91%

Comparative study of antioxidant capacity in organs of different Allium species

Štajner

Popović

2009

Open Life Sciences

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Cultivated and wild Allium species were investigated in order to compare the antioxidant capacity of their leaves and bulbs. Leaf and bulb anti-oxidative enzymes and scavenger activities, along with quantities of non-enzymic antioxidants, malonyl-dialdehyde and OH radicals were determined. Results obtained suggest that leaves possess higher anti-oxidant and scavenging activities than bulbs in the majority of cultivated and wild Allium species examined. Cultivation of some wild species such as A. flavum L., A. schoenoprasum L. and A. ursinum L. could be conducted in the future in order to produce Allium species with high antioxidant capacity in leaves and bulbs.

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Section: Resultssupporting

confidence: 91%

Comparative study of antioxidant capacity in organs of different Allium species

Štajner

Popović

2009

Open Life Sciences

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“…Data regarding the effect of polyphenol antioxidants on isoprostane concentration are apparently contradictory in the literature. For example, lack of effect has been described for polyphenols from chocolate (Ö ner-Iyidogan et al, 2004), red wine (Waddington et al, 2004), onions and black tea (O'Reilly et al, 2001). However, decrease of isoprostanes upon polyphenol intake has been reported for soy (Wiseman et al, 2000) and also for cocoa polyphenols (Wiswedel et al, 2004).…”

Section: Discussionmentioning

confidence: 99%

Pomegranate juice supplementation in chronic obstructive pulmonary disease: a 5-week randomized, double-blind, placebo-controlled trial

et al. 2005

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Objective: The aim of the present study is to investigate the effect of antioxidant polyphenol-rich pomegranate juice (PJ) supplementation for 5 weeks on patients with stable chronic obstructive pulmonary disease (COPD), since the oxidative stress plays a major role in the evolution and pathophysiology of COPD. Design: A randomized, double-blind, placebo-controlled trial was conducted. Subjects: A total of 30 patients with stable COPD were randomly distributed in two groups (15 patients each). Interventions: Both groups consumed either 400 ml PJ daily or matched placebo (synthetic orange-flavoured drink) for 5 weeks. Trolox Equivalent Antioxidant Capacity (TEAC) of PJ, blood parameters (14 haematological and 18 serobiochemical), respiratory function variables, bioavailability of PJ polyphenols (plasma and urine) and urinary isoprostane (8-iso-PGF 2a ) were evaluated. Results: The daily dose of PJ (containing 2.66 g polyphenols) provided 4 mmol/l TEAC. None of the polyphenols present in PJ were detected in plasma or in urine of volunteers. The most abundant PJ polyphenols, ellagitannins, were metabolized by the colonic microflora of COPD patients to yield two major metabolites in both plasma and urine (dibenzopyranone derivatives) with no TEAC. No differences were found (P40.05) between PJ and placebo groups for any of the parameters evaluated (serobiochemical and haematological), urinary 8-iso-PGF 2a , respiratory function variables and clinical symptoms of COPD patients. Conclusions: Our results suggest that PJ supplementation adds no benefit to the current standard therapy in patients with stable COPD. The high TEAC of PJ cannot be extrapolated in vivo probably due to the metabolism of its polyphenols by the colonic microflora. The understanding of the different bioavailability of dietary polyphenols is critical before claiming any antioxidantrelated health benefit. Sponsorship: 'Fundació n Séneca' (Murcia, Spain), Project PB/18/FS/02 and Spanish CICYT, Project AGL2003-02195.

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“…Total isoF2␣ levels in plasma were determined by immunoaffinity gas chromatography negative chemical ionization mass spectrometry as described previously. 15 Creatinine clearance was estimated using the Cockcroft-Gault method. 16 Estimated glomerular filtration rate (eGFR) was derived from creatinine levels as described by the Modification of Diet in Renal Disease Study and accounted for the age, sex, and racial origin of the subject.…”

Section: Laboratory Methodsmentioning

confidence: 99%

Asymmetric Dimethylarginine and Reduced Nitric Oxide Bioavailability in Young Black African Men

et al. 2007

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Abstract-Black Africans have a higher incidence of cardiovascular disease than white Europeans. We explored potential mechanisms of this excess risk by assessing endothelium function, inflammatory status (C-reactive protein), oxidative stress (isoprostane-F2␣), and plasma asymmetrical dimethyl arginine (ADMA; an endogenous competitive inhibitor of NO synthase) in each ethnic group. 1 This in part may be explained by an increased prevalence and severity in blacks of some risk factors for atherosclerosis. In particular, in black subjects, essential hypertension has a higher prevalence, earlier onset, and is associated with more severe end-organ damage, including left ventricular hypertrophy, renal failure, and stroke. 1 However, conventional risk factors for cardiovascular disease do not account for all of this increased risk. A recent study demonstrated that black ethnicity is a strong and independent risk factor for the development of peripheral arterial disease, which was not explained by higher levels of diabetes, hypertension, or body mass index. 2 The mechanisms underlying this ethnic predisposition to cardiovascular dysregulation remain unresolved.A number of studies have demonstrated that black subjects have endothelial dysfunction, 3-5 a key step in the initiation/ progression of atherosclerotic vascular disease. A hallmark of endothelial cell dysfunction is a reduction in the bioavailability of the antiatherosclerotic signaling molecule NO. 6 Longitudinal studies have demonstrated that a reduction in NO bioavailability is a predictor of accelerated atherosclerosis. 7,8 NO is generated by a family of NO synthases from L-arginine in a reaction that requires oxygen, reduced nicotinamideadenine dinucleotide phosphate, and essential cofactors, including tetrahydrobiopterin. NO bioavailability is principally determined by a reduction in its biosynthesis and/or inactivation by reactive oxygen species. Asymmetric dimethylargi-

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Consumption of flavonoids in onions and black tea: lack of effect on F2-isoprostanes and autoantibodies to oxidized LDL in healthy humans

Abstract: Flavonoid consumption in onions and tea had no significant effect on plasma F2-isoprostane concentrations and MDA-LDL autoantibody titer in this study and thus does not seem to inhibit lipid peroxidation in humans.

Cited by 118 publications

References 40 publications

Comparative study of antioxidant capacity in organs of different Allium species

Comparative study of antioxidant capacity in organs of different Allium species

Pomegranate juice supplementation in chronic obstructive pulmonary disease: a 5-week randomized, double-blind, placebo-controlled trial

Asymmetric Dimethylarginine and Reduced Nitric Oxide Bioavailability in Young Black African Men

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