A Comparative Study for the Evaluation of Two Doses of Ellagic Acid on Hepatic Drug Metabolizing and Antioxidant Enzymes in the Rat

The present study was designed to evaluate different doses of ellagic acid (EA) in vivo in rats for its potential to modulate hepatic phases I, II, and antioxidant enzymes. EA (10 or 30 mg/kg/day, intragastrically) was administered for 14 consecutive days, and activity, protein, and mRNA levels were determined. Although the cytochrome P450 (CYP) 2B and CYP2E enzyme activities were decreased significantly, the activities of all other enzymes were unchanged with the 10 mg/kg/day EA. In addition, western-blot and qRT-PCR results clearly corroborated the above enzyme expressions. On the other hand, while the NAD(P)H:quinone oxidoreductase 1 (NQO1), catalase (CAT), glutathione peroxidase (GPX), and glutathione S-transferase (GST) activities were increased significantly, CYP1A, 2B, 2C, 2E, and 19 enzyme activities were reduced significantly with 30 mg/kg/day EA. In addition, CYP2B, 2C6, 2E1, and 19 protein and mRNA levels were substantially decreased by the 30 mg/kg/day dose of EA, but the CYP1A protein, and mRNA levels were not changed. CYP3A enzyme activity, protein and mRNA levels were not altered by neither 10 nor 30 mg/kg/day ellagic acid. These results indicate that EA exerts a dose-dependent impact on the metabolism of chemical carcinogens and drugs by affecting the enzymes involved in xenobiotics activation/detoxification and antioxidant pathways

Effects of Cyclamen trochopteranthum on hepatic drug-metabolizing enzymes

The modulatory effects of the Cyclamen trochopterantum tuber extract on hepatic drug-metabolizing enzymes, including aniline 4-hydroxylase (A4H; CYP2E1), ethoxyresorufin O-deethylase (EROD; CYP1A), methoxyresorufin O-demethylase (MROD; CYP1A), caffeine N-demethylase (C3ND; CYP1A2) aminopyrene N-demethylase (APND; CYP2C6), and erythromycin N-demethylase (ERND; CYP3A1), were examined in vivo in rats. The activities of all of these enzymes were induced by the cyclamen extract. In addition, Western-blot and RT-PCR results clearly showed that CYP2E1, CYP1A1/CYP1A2 and CYP2C6 protein and mRNA levels were substantially increased by four different doses of cyclamen. Although, the CYP3A1 protein level was increased significantly, the mRNA level was not changed. These results indicate that cyclamen tuber extract might have a potential not only to inhibit and/or induce the metabolism of certain co-administered drugs but also influence the development of toxicity and carcinogenesis due to the induction of the cytochrome P450-dependent drug-metabolizing enzymes

Antioxidant and chemoprotective properties of Momordica charantia L. (bitter melon) fruit extract

Momordica charantia, commonly known as bitter melon, is used as a vegetable in number of countries. Extracts of M. charantia plant, fruit pulp, and seed have been reported to have a wide medicinal use in the traditional medical systems, most often as hypoglycemic and anti-diabetic agents. We have studied the effect of M. charantia, collected from Kazdaglari (Mount Ida) in Balikesir, fruit extract on glutathione S-transferases (GSTs), cytochrome P450s (CYPs), and antioxidant enzymes in rats. Male Wistar rats, aged 12 weeks and weighing 200-250 g, were given 200 mg M. charantia fruit extract per kg body weight, i.p., for four consecutive days. At the end of the experimental period, the animals were sacrificed, and liver, kidney, and lung were isolated. Our results have indicated significant increase in especially hepatic antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) activities. The strongest increase (about 9-fold) was observed in GPx activities while about 2 to 5-fold increases were observed in SOD and CAT. M. charantia fruit extract also exhibited hepatoprotective effects in CCl4-intoxicated rats. In addition, about 50% increase was also noted with hepatic cytosolic GSTs. On the other hand, treatments of rats with M. charantia significantly reduced both ethoxyresorufin O-deethylase (EROD) and methoxyresorufin O-deethylase (MROD) activities in rat liver microsomes, which are known to be catalyzed by CYP1A isoforms These results suggest that the M. charantia fruit extract possesses the anti-oxidant effects besides having protective activities in rats. © 2007 Academic Journals

Purification and Characterization of Cytochrome P450 Reductase from Liver Microsomes of Feral Leaping Mullet (Liza saliens)

NADPH-cytochrome P450 reductase was purified to electrophoretic homogeneity from detergent-solubilized liver microsomes from the leaping mullet (Liza saliens). The purified reductase was characterized with respect to spectral, electrophoretic, and biocatalytic properties. In addition, effects of pH, ionic strength, and the substrate concentration on the NADPH-dependent cytochrome c reductase activity of the purified fish liver cytochrome P450 reductase were studied. Cytochrome P450 reductase was purified 438-fold with a yield of 17.5% with respect to the initial amount present in the fish liver microsomes. The specific activity of the enzyme was found to be 52.6 mu mol cytochrome c reduced per minute per mg protein. The monomer molecular weight of the purified enzyme was calculated to be 77,000 +/- 1000 when electrophoresed on polyacrylamide gels under the denaturing conditions in the presence of SDS. The absorption spectrum of fish reductase showed two peaks at 378 and 455 nm. NADPH-dependent cytochrome c reductase activity of the purified Liza saliens liver cytochrome P450 reductase was found to be maximal when pH was between 7.4 and 7.8. The apparent K-m of the purified enzyme was found to be 7.69 mu M for cytochrome c when the enzyme activity was measured in 0.3 M potassium phosphate buffer, pH 7.7, at room temperature, and the enzyme was fully saturated by its substrate, cytochrome c, when the substrate concentration was at or above the 70 mu M. Furthermore, the purified enzyme was biocatalytically active in reconstituting the 7-ethoxyresorufin O-deethylase activity in the reconstituted system containing purified mullet liver cytochrome P4501A1 and lipid. These results suggested that the purified fish liver cytochrome P450 reductase is similar to its mammalian counterparts with respect to spectral, electrophoretic, and biocatalytic properties. (C) 1997 John Wiley & Sons, Inc. J Biochem Toxicol 12: 103-113, 199