0000000000169787
AUTHOR
Marie-hélène Siess
showing 12 related works from this author
Comparison of the chemopreventive efficacies of garlic powders with different alliin contents against aflatoxin B1 carcinogenicity in rats
2004
Garlic (Allium sativum) is well known for its beneficial effects on health and particularly for its chemopreventive potential against cancer. The present study was designed to compare the chemopreventive efficacies of several garlic powders with various levels of alliin, a precursor of active sulfur compounds. For this purpose we used the medium-term hepatocarcinogenesis protocol (resistant hepatocyte model), which allows the detection of preneoplasic foci expressing the placental form of glutathione S-transferase (GST-P) as an end-point. Rats were fed diets containing three garlic powders (5% of the diet) with various alliin contents for 3 weeks. Garlic powders were obtained from bulbs gro…
Potential role of flavonoids in cancer prevention
1997
International audience
Enhancement of glutathione transferase activity in rat by dietary administration of flavonoids: organ specificity, dose response and time-course stud…
1995
International audience
Inhibition of ethoxyresorufin deethylase activity by natural flavonoids in human and rat liver microsomes
1990
Several flavones and flavonols (chrysin, quercetin, luteolin, flavone and 7, 8-benzoflavone) were found to inhibit ethoxyresorufin deethylase (EROD) activity in human and rat liver microsomes. In man, molecules without hydroxyl groups are more powerful inhibitors than polyhydroxylated flavonoids (7, 8-benzoflavone greater than flavone greater than chrysin greater than luteolin greater than quercetin greater than morin). In rat, chrysin was the strongest inhibitor and the less effective were morin and 7,8-benzoflavone. For all molecules human microsomes were more sensitive than rat microsomes. The most important difference concerned 7,8-benzoflavone which was 10,000-fold more potent in man.
Effects of garlic powders with varying alliin contents on hepatic drug metabolizing enzymes in rats
2003
International audience; The anticarcinogenic effect of garlic has been demonstrated in both epidemiologic and experimental studies. In this study, possible mechanisms involved in the anticarcinogenic effect of garlic consumption were assessed by determining its capacity to alter drug metabolizing enzymes, in relation with its alliin content. Rats were fed a diet for 2 weeks containing 5% garlic powders produced from bulbs grown on soils with different levels of sulfate fertilization and therefore containing differing amounts of alliin. Activities of several hepatic enzymes, which are important in carcinogen metabolism such cytochromes P450 (CYP) and phase II enzymes, were determined. Garlic…
Differential Effects of Nonhydroxylated Flavonoids as Inducers of Cytochrome P450 1A and 2B Isozymes in Rat Liver
1996
Flavanone, flavone, and tangeretin differentially affected the activities of cytochrome P540 1A and 2B isozymes in rat liver. Flavone and, to a lesser extent, tangeretin, increased activities of ethoxyresorufin O-deethylase, methoxyresorufin O-demethylase, and pentoxyresorufin O-dealkylase (PROD), whereas flavanone mainly enhanced PROD activity. Immunoblot analysis indicated that flavone and tangeretin increased cytochrome P450 1A1, 1A2, and 2B1,2 forms, whereas flavanone only enhanced the cytochrome P450 2B isozymes. Northern blot study showed that flavone and tangeretin increased the level of the cytochrome P450 1A2 mRNAs. The concentration of the other mRNAs were slightly or not affected…
Antimutagenic activity of organosulfur compounds from Allium is associated with phase II enzyme induction
2001
In a previous study, we showed that naturally occurring organosulfur compounds (OSCs) from garlic and onion modulated the activation of carcinogen via the alteration of cytochromes P450. The present study was undertaken to determine the incidence of the in vivo induction of phase II enzymes by individual OSCs on the genotoxicity of several carcinogens. Diallyl sulfide (DAS), diallyl disulfide (DADS), dipropyl sulfide (DPS) and dipropyl disulfide (DPDS), were administered by gavage (1mmol/kg) to male SPF Wistar rats for 4 consecutive days. The effects of treatments on phase II enzymes and on the genotoxicity of carcinogens were evaluated with hepatic cytosols and microsomes from OSCs-treated…
Liver subcellular fractions from rats treated by organosulfur compounds from Allium modulate mutagen activation
2000
The effects of in vivo administration of naturally occurring organosulfur compounds (OSCs) from Allium species were studied on the activation of several mutagens. Male SPF Wistar rats were given p.o. one of either diallyl sulfide (DAS), diallyl disulfide (DADS), dipropyl sulfide (DPS) or dipropyl disulfide (DPDS) during 4 consecutive days and the ability of hepatic S9 and microsomes from treated rats to activate benzo[a]pyrene (BaP), cyclophosphamide (CP), dimethylnitrosamine (DMN), N-nitrosopiperidine (N-PiP) and 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) was determined in the Ames test. Administration of DAS, DPS and DPDS resulted in a significant increase of the activation of…
Metabolism of apigenin by rat liver phase I and phase II enzymes and by isolated perfused rat liver
2004
The metabolism of apigenin, a low estrogenic flavonoid phytochemical, was investigated in rat using liver models both in vitro (subcellular fractions) and ex vivo (isolated perfused liver). In vitro, phase I metabolism led to the formation of three monohydroxylated derivatives: luteolin which was the major metabolite (K(m) = 22.5 +/- 1.5 microM; V(max) = 5.605 +/- 0.090 nmol/min/mg protein, means +/- S.E.M.), scutellarein, and iso-scutellarein. These oxidative pathways were mediated by cytochrome P450 monooxygenases (P450s). The use of P450 inhibitors and inducers showed that CYP1A1, CYP2B, and CYP2E1 are involved. In vitro studies of phase II metabolism indicated that apigenin underwent co…
Different effects of flavonoids on cytochrome P450 3A4- dependent nifedipine oxidation in human liver microsomes
1995
National audience
Post-initiation modulating effects of allyl sulfides in rat hepatocarcinogenesis
2004
Effects of administration of diallyl sulfide (DAS) and diallyl disulfide (DADS) on the promotion stage of hepatocarcinogenesis were investigated in rats using the Ito model. They were compared with those of phenobarbital (PB), a well-known liver promoter in rats. Initiation was induced by a single dose of N-nitrosodiethylamine (NDEA) and 3 weeks later, a partial hepatectomy was conducted. Two weeks after the NDEA injection, rats received either 0.05% allyl sulfides, PB or both in their diet for 8 weeks. Feeding with DAS increased the number of liver preneoplastic foci by 63% with respect to the untreated group. However, rats fed DAS showed a lower foci development than rats fed PB. The DADS…
Flavonoids of honey and propolis : characterization and effects on hepatic drug-metabolizing enzymes and benzo(a)pyrene-DNA binding in rats
1996
The influence of dietary sunflower honey, propolis, and a flavonoid extract of propolis was examined on drug-metabolizing enzyme activities in rat liver and on microsome-mediated binding of benzo[a]pyrene to DNA. Characterization of flavonoids present in sunflower honey and propolis was achieved in order to assess the relative effects of different components of honey and propolis. Honey and propolis contained the same major flavonoids, pinocembrin, chrysin, galangin, and pinobanksin. The concentration of flavonoids was higher in propolis. Sunflower honey produced no significant changes on phase I and phase II enzyme activities and no modification of in vitro binding of benzo[a]pyrene to DNA…