Effect of natural phenols on the catalytic activity of cytochrome P450 2E1.

The effect of protocatechuic acid, tannic acid and trans-resveratrol on the activity of p-nitrophenol hydroxylase (PNPH), an enzymatic marker of CYP2E1, was examined in liver microsomes from acetone induced mice. trans-Resveratrol was found to be the most potent inhibitor (IC(50) = 18.5 +/- 0.

Monoclonal antibody-directed analysis of benzo[a]pyrene metabolism in rat liver and extrahepatic tissues: effect of propyl and octyl gallate.

Monoclonal antibody (MAb) 1-7-1 against 3-methylcholanthrene (MC)-induced forms of cytochrome P-450 (CYP) was used to characterize benzo[a]pyrene (B[a]P) metabolism in rat liver and extrahepatic tissues and its modulation by phenolic antioxidants, propyl and octyl gallates. Male Wistar rats were treated with these food additives (50 mg/kg body wt i.p.

Effect of tannic acid on benzo[a]pyrene-DNA adduct formation in mouse epidermis: comparison with synthetic gallic acid esters.

Tannic acid, a naturally occurring plant phenol, was shown to inhibit the mutagenicity and/or tumorigenicity of several polycyclic aromatic hydrocarbons in mouse skin. In this study the effect of topical application of tannic acid on epidermal aryl hydrocarbon hydroxylase, glutathione S-transferase, and binding of benzo[a]pyrene (B[a]P) to epidermal DNA was compared with the activity of synthetic gallic acid esters. Single topical application of 8 mumol octyl and dodecyl gallate had no effect on the induction of aryl hydrocarbon hydroxylase, whereas propyl gallate and tannic acid increased the enzyme activity by nearly 200%.

Effect of toluidines on drug metabolizing enzymes in rat liver, kidney and lung.

The effect of pretreatment with o-, m- and p-toluidine on the drug-metabolizing enzymes of liver, kidney and lung in rats were investigated. The activities of microsomal aryl hydrocarbon hydroxylase (AHH), aminopyrine demethylase, NADPH-cytochrome c reductase, epoxide hydrolase, cytosolic glutathione S-transferase as well as the concentrations of cytochrome P-450 and cytochrome b5 were determined. The obtained results showed that o-toluidine increased the activity of AHH in all tested organs; a particularly marked increase was observed in the kidney.

The effect of sesquiterpene lactones, eupatoriopicrin and hydroxyisonobilin, on the glycolytic metabolism of human lymphocytes.

The effect of two sesquiterpene lactones of the germacranolide group, eupatoriopicrin and hydroxyisonobilin, on the glycolytic metabolism of human lymphocytes stimulated by phytohemagglutinin was tested. Glucose and lactic acid levels as well as the activities of phosphofructokinase, glyceraldehyde 3-phosphate dehydrogenase, pyruvate kinase, and lactate dehydrogenase were measured. Both lactones caused a decrease in glucose consumption and lactic acid formation as well as the inhibition of the tested enzymes.

[Effect of anticoagulants on lymphocyte isolation by density gradient centrifugation].

The authors compared the efficiency of isolation and the purity of lymphocytes obtained by the method of centrifugation in a gradient of ficoll and uropoline from blood obtained on ACD fluid and on heparin. Isolation of lymphocytes from the blood obtained on heparin was more efficient (60%) and useful. For removal of platelets it was necessary to use additional centrifugation in a saccharose gradient or application of aggregating agents during isolation of lymphocytes obtained on heparin or ACD fluid.