"7"^^ . . . "Phytotherapy Research" . "Effect of silybin and its congeners on human liver microsomal cytochrome P450 activities" . "Effect of silybin and its congeners on human liver microsomal cytochrome P450 activities"@en . . "Silybin a jeho p\u0159\u00EDbuzn\u00E9 flavonolignany jsou hlavn\u00EDmi slo\u017Ekami extraktu ze Silybum marianum, silymarinu, kter\u00FD byl po stovky let pou\u017E\u00EDv\u00E1n k l\u00E9\u010Db\u011B jatern\u00EDch onemocn\u011Bn\u00ED. A\u010Dkoliv je pova\u017Eov\u00E1n za bezpe\u010Dn\u00FD, mnoho jeho slo\u017Eek nebylo nikdy testov\u00E1no v souvislosti s biotransformac\u00ED l\u00E9\u010Div. Cytochromy P450 (CYP) jsou v tomto ohledu velmi d\u016Fle\u017Eit\u00E9. Testovali jsme \u00FA\u010Dinky \u010Dty\u0159 flavonolignan\u016F: silybinu, jeho semisyntetick\u00E9ho deriv\u00E1tu dehydrosilybinu, silydianinu a silychristinu na t\u0159i specifick\u00E9 CYP aktivity: bufuralol 1\u00B4-hydroxylaci (CYP2D6), p-nitrofenol hydroxylaci (CYP2E1) a oxidaci nifedipinu (CYP3A4). V\u0161echny flavonolignany vykazovaly inhibici t\u011Bchto aktivit v z\u00E1vislosti na d\u00E1vce, s hodnotou IC50 v mikromol\u00E1rn\u00ED oblasti. Inhibice byla kompetitivn\u00ED nebo sm\u00ED\u0161en\u00E1, co\u017E uk\u00E1zaly grafy dvojit\u011B reciprok\u00E9 z\u00E1vislosti. Ov\u0161em tato inhibice nen\u00ED relevantn\u00ED pro terapii, proto\u017Ee fyziologick\u00E9 koncentrace jednotliv\u00FDch flavonolignan\u016F nep\u0159esahuj\u00ED 0,5 mikromol\u00E1rn\u00ED. Data podporuj\u00ED vyu\u017Eit\u00ED extraktu jako potravn\u00EDho dopl\u0148ku."@cs . "Effect of silybin and its congeners on human liver microsomal cytochrome P450 activities" . . "7" . "0951-418X" . "Zuber, Roman" . "\u00DA\u010Dinky silybinu a jeho deriv\u00E1t\u016F na aktivitu cytochrom\u016F P450 v mikrosomech lidsk\u00FDch hepatocyt\u016F"@cs . "Effect of silybin and its congeners on human liver microsomal cytochrome P450 activities"@en . "Rohovsk\u00FD, Petr" . . . "\u0160im\u00E1nek, Vil\u00EDm" . . "7"^^ . . "P(GA303/99/P002), Z(MSM 151100003)" . "5"^^ . "cytochrome P450; Silybum marianum; flavonolignans; microsomes; human"@en . . "Ulrichov\u00E1, Jitka" . . . "644317" . . . "16" . . . . "RIV/61989592:15110/02:00006948" . . . . . "US - Spojen\u00E9 st\u00E1ty americk\u00E9" . "Dvo\u0159\u00E1k, Zden\u011Bk" . "Silybin and related flavonolignans form a major part of the Silybum marianum extract, silymarin, which has been used to treat liver diseases for hundreds of years. Although regarded as safe, many of the extract constituents remain thus far untested for their possible effects on liver biotransformation enzymes. Cytochromes P450 (CYP) are very important in this regard. We tested the effect of four flavonolignans: silybin, its hemisynthetic derivative dehydrosilybin, silydianin, and silycristin on three specific CYP activities: bufuralol 1'-hydroxylation (CYP2D6), p-nitrophenol hydroxylation (CYP2E1), and nifedipine oxidation (CYP3A4). All flavonolignans displayed dose-dependent inhibition of these activities with IC(50) values in the micromolar range. The inhibition was competitive or mixed as revealed by double reciprocal plots of kinetic experiments. However, the inhibition is not considered to be relevant for therapy because physiological concentrations of the individual flavonolignans do not ex" . "[2497A6D4A928]" . . "Modriansk\u00FD, Martin" . "15110" . "Anzenbacher, Pavel" . "RIV/61989592:15110/02:00006948!RIV09-MSM-15110___" . . . "\u00DA\u010Dinky silybinu a jeho deriv\u00E1t\u016F na aktivitu cytochrom\u016F P450 v mikrosomech lidsk\u00FDch hepatocyt\u016F"@cs . "Silybin and related flavonolignans form a major part of the Silybum marianum extract, silymarin, which has been used to treat liver diseases for hundreds of years. Although regarded as safe, many of the extract constituents remain thus far untested for their possible effects on liver biotransformation enzymes. Cytochromes P450 (CYP) are very important in this regard. We tested the effect of four flavonolignans: silybin, its hemisynthetic derivative dehydrosilybin, silydianin, and silycristin on three specific CYP activities: bufuralol 1'-hydroxylation (CYP2D6), p-nitrophenol hydroxylation (CYP2E1), and nifedipine oxidation (CYP3A4). All flavonolignans displayed dose-dependent inhibition of these activities with IC(50) values in the micromolar range. The inhibition was competitive or mixed as revealed by double reciprocal plots of kinetic experiments. However, the inhibition is not considered to be relevant for therapy because physiological concentrations of the individual flavonolignans do not ex"@en .