Wyniki wyszukiwania

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Effect of quercetin on paraoxonase 1 activity - studies in cultured cells, mice and humans

100%

Boesch-Saadatmandi C., Egert S., Schrader C., Coumoul X., Barouki R., Muller M. J., Wolffram S., Rimbach G.

Journal of Physiology and Pharmacology

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2010

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tom 61

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nr 1

99-105

There is increasing evidence that the HDL-associated enzyme paraoxonase 1 (PON1) may have a protective function in the atherosclerotic process. An enhancement of PON1 activity by dietary factors including flavonoids is therefore of interest. Quercetin, a flavonol frequently present in fruits and vegetables has been shown to induce PON1 in cultured liver cells, but the in vivo efficacy of a dietary quercetin supplementation has yet not been evaluated. To this end, we fed laboratory mice quercetin-enriched diets with quercetin concentrations ranging from 0.05 to 2 mg/g diet for 6 weeks and determined the expression of the hepatic PON1 gene and its protein levels. Since we could establish a moderate but significant induction of PON1 mRNA levels by dietary quercetin in mice, we aimed to proof whether healthy human volunteers, given graded supplementary quercetin (50, 100 or 150 mg/day) for two weeks, would respond with likewise enhanced plasma paraoxonase activities. However, PON1 activity towards phenylacetate and paraoxon was not changed following quercetin supplementation in humans. Differences between mice and humans regarding the PON1 inducing activity of quercetin may be related to differences in quercetin metabolism. In mice, unlike in humans, a large proportion of quercetin is methylated to isorhamnetin which exhibits, according to our reporter gene data in cultured liver cells, a potent PON1 inducing activity.

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Studies of the ability of rhamnetin and isorhamnetin to alkylate bacterial DNA

100%

Czeczot H.

Acta Microbiologica Polonica

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1994

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tom 43

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nr 3-4

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Antioxidative activity of flavonoids in stimulated human neutrophils

100%

Zielinska M., Kostrzewa A., Ignatowicz E.

Folia Histochemica et Cytobiologica

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2000

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tom 38

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nr 1

4

A study of the genotoxic potential of flavonoids using short-term bacterial assays

100%

Czeczot H., Kusztelak J.

Acta Biochimica Polonica

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1993

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tom 40

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nr 4

Genotoxic activities of flavonoids (quercetin, rhamnetin, isorhamnetin, apigenin, Iuteolin) were investigated using two short-term bacterial assays. In the "repair test" in Salmonella typhimurium (strains TA1538 uvrB' and TA1978 uvrB+) the flavonoids studied did not introduce any damage into the DNA recognized by UvrABC nuclease (correndonuclease II). The results of the SOS-Chromotest in Escherichia coli K-12 strains PQ37 (tag*, alk+) and PQ243 (tagA, alkA) indicated that flavonoids only weakly induced the SOS system. The addition of a liver activation system (S9 mix) did not increase the mutagenic effect of the flavonoids tested. Two compounds: rhamnetin, isorhamnetin and their putative metabolites formed in the presence of the S9 mix did not alkylate DNA at N-3 of adenine.

Ograniczanie wyników

1 Acta Biochimica Polonica

1 Acta Microbiologica Polonica

1 Folia Histochemica et Cytobiologica

1 Journal of Physiology and Pharmacology

2 Czeczot H.

1 Barouki R.

1 Boesch-Saadatmandi C.

1 Coumoul X.

1 Egert S.

1 Ignatowicz E.

1 Kostrzewa A.

1 Kusztelak J.

1 Muller M. J.

1 Rimbach G.

1 Schrader C.

1 Wolffram S.

1 Zielinska M.

1 2010

1 2000

1 1994

1 1993

Effect of quercetin on paraoxonase 1 activity - studies in cultured cells, mice and humans

Studies of the ability of rhamnetin and isorhamnetin to alkylate bacterial DNA

Antioxidative activity of flavonoids in stimulated human neutrophils

A study of the genotoxic potential of flavonoids using short-term bacterial assays