Inhibition of Low Density Lipoprotein Oxidation by Myrigalone B, a Naturally Occurring Flavonoid

Mathiesen, Liv; Malterud, Karl Egil; Nenseter, Marit S.; Sund, Reidar Bredo

doi:10.1111/j.1600-0773.1996.tb00195.x

Cited by 16 publications

(7 citation statements)

References 21 publications

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“…This study supports previous findings that antioxidant vitamins prolong lag time and retard oxidation during the propagation phase of LDL modification (Yen and Hsieh 2002;Mathiesen et al 1996aMathiesen et al , 1996bVaya et al 1997). Ascorbic acid and Trolox had lag times of 108.26 ± 3.13 min and 130.59 ± 9.84 min, respectively; however, the former was not significantly different from the control, oxLDL.…”

Section: Discussionsupporting

confidence: 93%

Medicinal plants of Cree communities (Québec, Canada): antioxidant activity of plants used to treat type 2 diabetes symptomsThis article is one of a selection of papers published in this special issue (part 2 of 2) on the Safety and Efficacy of Natural Health Products.

Fraser

Cuerrier

Haddad

et al. 2007

Can. J. Physiol. Pharmacol.

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Traditional medicines (TM) used to treat symptoms of diabetes by two Cree communities were assessed for their free radical scavenging activity using the stable 1,1-diphenyl-2-picrylhydrazyl radical, and their ability to protect human low-density lipoprotein from Cu2+-mediated oxidation by measuring lag time before the appearance of conjugated dienes and formation of thiobarbituric acid-reactive substances. Water-soluble phenolic content was also measured. A total of 20 medicinal plants from Whapmagoostui and 16 from Mistissini were compared with 16 extracts of plants that were not used medicinally. Medicinal plant extracts, particularly those from Larix laricina, displayed high antioxidant activity, comparable with ascorbic acid, Trolox, and the known antioxidant flavonoids quercetin, epicatechin, catechin. Extracts of Pinaceae and Ericaceae contained the highest levels of phenolics. Factors such as season and area of plant collection, as well as the plant part from which the extract was derived, affected antioxidant activity. Positive correlations were found between the established traditional knowledge of Cree Elders and Healers and the antioxidant activity for medicinal plants used in Mistissini (r = 0.3134; p = 0.058) and in Whapmagoostui (r = 0.5165; p = 0.001). Significant correlations between phenolic content were also seen with the existing ethnobotanical data (r = 0.5015; p = 0.003) and bioassays (r = 0.4178; p = 0.003). These results indicate that a clear majority of plants used by the Cree are excellent sources of antioxidants.

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Section: Discussionsupporting

confidence: 93%

Medicinal plants of Cree communities (Québec, Canada): antioxidant activity of plants used to treat type 2 diabetes symptomsThis article is one of a selection of papers published in this special issue (part 2 of 2) on the Safety and Efficacy of Natural Health Products.

Fraser

Cuerrier

Haddad

et al. 2007

Can. J. Physiol. Pharmacol.

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“…Due to the epidemiological evidence indicating an inverse relationship between dietary fruit and vegetable intake and the incidence of cardiovascular disease [20,21], numerous studies have been undertaken to show that micronutrients provided by such diets, including α-tocopherol [22,23], ascorbic acid [24][25][26][27] and various flavonoids [28][29][30][31], can protect LDL from oxidative modification [32]. Under certain circumstances, however, they have been shown to display prooxidant activity.…”

Section: Introductionmentioning

confidence: 99%

Mechanism of the antioxidant to pro-oxidant switch in the behavior of dehydroascorbate during LDL oxidation by copper(II) ions

Horsley

Burkitt

Jones

et al. 2007

Archives of Biochemistry and Biophysics

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Subject area: Systems biochemistryAbbreviations: BCDS, bathocuproine disulphonic acid; DMPO,5, EPR, electron paramagnetic resonance; 13-HPODE, 13(S)-hydroperoxyoctadeca-9Z,11E-dienoic acid 2 ABSTRACTOxidised low density lipoprotein (LDL) may be involved in the pathogenesis of atherosclerosis.We have therefore investigated the mechanisms underlying the antioxidant/pro-oxidant behavior of dehydroascorbate, the oxidation product of ascorbic acid, toward LDL incubated with Cu 2+ ions. By monitoring lipid peroxidation through the formation of conjugated dienes and lipid hydroperoxides, we show that the pro-oxidant activity of dehydroascorbate is critically dependent on the presence of lipid hydroperoxides, which accumulate during the early stages of oxidation.Using electron paramagnetic resonance spectroscopy, we show that dehydroascorbate amplifies the generation of alkoxyl radicals during the interaction of copper ions with the model alkyl hydroperoxide, tert-butylhydroperoxide. Under continuous-flow conditions, a prominent doublet signal was detected, which we attribute to both the erythroascorbate and ascorbate free radicals.On this basis, we propose that the pro-oxidant activity of dehydroascorbate toward LDL is due to its known spontaneous interconversion to erythroascorbate and ascorbate, which reduce Cu 2+ to Cu + and thereby promote the decomposition of lipid hydroperoxides. Various mechanisms, including copper chelation and Cu + oxidation, are suggested to underlie the antioxidant behavior of dehydroascorbate in LDL that is essentially free of lipid hydroperoxides.

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“…The ability of flavonoids to inhibit the oxidation of low-density lipoproteins (LDLs) demonstrates their potential as chain-breaking antioxidants [3][4][5][6][7][8] and this might involve a role in the sparing of α-…”

Section: Introductionmentioning

confidence: 99%

Structural dependence of flavonoid interactions with Cu2+ ions: implications for their antioxidant properties

Brown

Khodr

Hider

et al. 1998

Biochemical Journal

737

389

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The flavonoids constitute a large group of polyphenolic phytochemicals with antioxidant properties in vitro. The interactions of four structurally related flavonoids (quercetin, kaempferol, rutin and luteolin) with Cu2+ ions were investigated in terms of the extent to which they undergo complex formation through chelation or modification through oxidation, as well as in their structural dependence. The ortho 3ʹ,4ʹ-dihydroxy substitution in the B ring is shown to be important for Cu2+-chelate formation, thereby influencing the antioxidant activity. The presence of a 3-hydroxy group in the flavonoid structure enhances the oxidation of quercetin and kaempferol, whereas luteolin and rutin, each lacking the 3-hydroxy group, do not oxidize as readily in the presence of Cu2+ ions. The results also demonstrate that the reactivities of the flavonoids in protecting low-density lipoprotein (LDL) against Cu2+ ion-induced oxidation are dependent on their structural properties in terms of the response of the particular flavonoid to Cu2+ ions, whether chelation or oxidation, their partitioning abilities between the aqueous compartment and the lipophilic environment within the LDL particle, and their hydrogen-donating antioxidant properties.

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Inhibition of Low Density Lipoprotein Oxidation by Myrigalone B, a Naturally Occurring Flavonoid

Cited by 16 publications

References 21 publications

Medicinal plants of Cree communities (Québec, Canada): antioxidant activity of plants used to treat type 2 diabetes symptomsThis article is one of a selection of papers published in this special issue (part 2 of 2) on the Safety and Efficacy of Natural Health Products.

Medicinal plants of Cree communities (Québec, Canada): antioxidant activity of plants used to treat type 2 diabetes symptomsThis article is one of a selection of papers published in this special issue (part 2 of 2) on the Safety and Efficacy of Natural Health Products.

Mechanism of the antioxidant to pro-oxidant switch in the behavior of dehydroascorbate during LDL oxidation by copper(II) ions

Structural dependence of flavonoid interactions with Cu2+ ions: implications for their antioxidant properties

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