• Mass Spectrometry Letters
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• 제11권4호
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• pp.113-117
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• 2020

Cytochrome P450 2J2 (CYP2J2) is a member of the cytochrome P450 superfamily, and is known to be arachidonic acid epoxygenase that mediates the formation of four bioactive regioisomers of epoxyeicosatrienoic acids (EETs). CYP2J2 is also involved in the metabolism of drugs such as albendazole, astemizole, danazol, ebastine, and terfenadine. CYP2J2 is highly expressed in the heart and cancer tissues. In this study, the inhibitory potential of ten natural products against CYP2J2 activity was evaluated using human liver microsomes and tandem mass spectrometry. Among them, bilobetin, which is a kind of biflavonoid, exhibits a strong inhibitory effect against the CYP2J2-mediated astemizole O-demethylation (IC50 = 0.73 μM) and terfenadine hydroxylation (IC50 = 0.89 μM). This result suggests that bilobetin can be used as strong CYP2J2 inhibitor in drug metabolism study.

• Archives of Pharmacal Research
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• 제15권1호
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• pp.78-86
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• 1992

The induction of hepatic cytochromes P450 and metabolic effects have been examined in male and female Sprague-Dawley rats following treatment with either phenobarbital or 3-methylcholanthrene. Hepatic cytochrome P450 levels were higher in males than in females by ~40%. Treatment of male and female rats with phenobarbital or 3-methylcholanthrene resulted in an ~1.6 and 2-fold increase, respectively, in heptic microsomal cytochrome P450 levels in both sexes, relative to untreated animals. Immunoblot analyses were performed to compare sex-related changes in P450 levels. Hepatic P45IIB1 levels in males were greater than those in females following phenobarbital treatment. 3-Methylcholanthrene-induced male hepatic microsomes exhibited greater levels of P450 females failed to exhibit a band. Mab PCN 2-13-1 against P-45-IIIA recognized an intense in uninduced microsomes from female rats. The levels of P450IIIA in males were increased 2 to 3-fold following treatment with phenobarbital, while the increase of IIIA levels in females by phenobarbital was minimal, as monitored by immunoblot analysis. Solid phase radiommunoassay using monoclonal antibodies supported the results of immunoblot analysis. Phenobarbital treatment caused a 6.5-fold increase in the monoclonal iantibody binding to IIBI in males, whereas treatment of females with phenobarbital resulted of IA levels by 3-methylcholanthrene was also greater in females than in males (10-vs. 8-fold) although the levels of induced IA were comparable inboth sexes, as assessed by radiommunoassay. Radioimmunoassay also showed that hepatic IIEI level was 1.5-fold higher in males than in females and that either phenobarbital or 3-methylcholanthrene treatment caused 80% to 40% decrease in IIEL levels, relative to control, in both sexes. Sex-related metabolic activities were examined in hepatic microsomes. Hexobarbital hydroxylase activity was 2-to 3-fold higher in uninduced microsomes from males than that from females. This hydroxylase activity was increased 2-and 3-fold in males and females, respectively, following phenobarbital treatment, as compared to controls. Addition females produced 64% and 84% inhibition of hexobarbital oxidation, respectively. Aryl hydrocarbon hydroxylase activity was increased -12 and 26-fold in males and females respectively. Following phenobarbital treatment, as compared to controls. Addition of anti-P450IIB1 antibody to phenobarbital-induced hepatic microsomes from males and females produced 64% and 84% inhibition of hexobarbital oxidation, respectively. Aryl hydrocarbon hydroxylase activity was increased -12 and 26 fold in males and females, respectively, following 3-methylcholanthrene treatment relative to controls. The anti-P-450IA antibody inhibitable rate of aryl hydrocarbon hydroxylase activity was comparable in both sexes following 3-methylcholanthrene treatment relative to controls. The anti-P450LA antibody inhibitable rate of aryl hydrocarbon hydroxylase activity was comparable in both sexes following 3-methylcholanthrene treatment (-70%). These results demonstrate that levels of hepatic P450IIB1 or P450IA are greater in male than in female for untreated, phenobarbital-or-3-methylcholanthrene treated rats. In addition, the relative for untreated phenobarbital-or 3-methylcholanthrene treated rats. In addition, the relative increase of phenobarbital-or 3-methylcholanthrene treated rats. In addition, the relative increase of phenobarbital-or 3-methylcholanthrene treated rats. In addition, the relative increase of P450IIB1 or IA phenobarbital or 3-methylcholanthrene is more significant in females.

• Bulletin of the Korean Chemical Society
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• 제19권3호
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• pp.375-378
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• 1998

• Archives of Pharmacal Research
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• 제23권6호
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• pp.599-604
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• 2000

$\beta$-Sitosterol, campesterol and stigmasterol have been known to the phytosterols the most frequently found in plants. Metabolism of phytosterols was investigated using rat feces and liver microsomes. Feces were collected after phytosterols (a well characterized mixture of $\beta$-sitosterol 40%, campesterol 30% and dihydrobrasicasterol) were administered orally (0.5 ${g/kg$) to rats. Metabolites of phytosterols were identified using GC/MS. Three peaks were eluted at 12.47, 12.65, 12.87 min and had characteristic molecular ions m/z 428, 430, 432, respectively. Three fecal metabolites were identified as androstadienedione, androstenedione, and androstanedione. No metabolites could be detected in the rat liver microsomal reaction mixture. The results suggest that the metabolites of phytosterols in rat feces are formed by oxidation at 3- position, saturation at 5- and 6- position, and 17- side chain cleavage in the rat large intestine.

• BMB Reports
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• 제34권2호
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• pp.118-122
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• 2001

The translocation of ribose-binding protein (RBP) into the inverted membrane vesicles (IMV) of Escherichia coli and eukaryotic microsomes was studied using the in vitro translation/translocation system. It was found that RBP was translocated into heterologous eukaryotic microsomes co-translationally, as well as post-translationally However, RBP was translocated only past-translationally into IMV. Degradation fragments of RBP with the molar mass of 14 and 16 kDa were produced during the translocation into IMV However, the amount of the degradation products decreased and the mature form of RBP appeared in the presence of phenylmethylsulfonyl fluoride (PMSF). PMSF and GTP accelerated the translocation of RBF It was also found that SecB enhanced the post-translational translocation of RBP It appears that RBP is translocated via at least two targeting paths.

• 한국식품영양과학회지
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• 제30권3호
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• pp.547-551
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• 2001

The comparative activities of acetone, ethanol, and aqueous fractions extracted from fruit powder of Cudrania tricuspidata by different temperature were tested by in vitro experimental models; peroxidation of linoleic acid and autooxidation of rat hepatic and renal microsomes by using thiobarbituric acid (TBA) for assay of free malondialdehyde production, and scavenging activities of free radicals by DPPH (α, α'-diphenyl-β-picrylhydrazyl). In DPPH method, acetone fraction extracted at 30℃ showed the highest free radical scavenging activities and acetone fractions extracted at 30℃ and 60℃ and ethanol fraction extracted at 30℃ showed stronger than BHT (butylated hydroxitoluene) although used ten-fold lower concentrations. In thiocyanate method used linoleic acid an inhibitory effects of all fractions showed higher than control treatment. TBA method used linoleic acid showed the highest antioxidative activity in acetone fraction extracted at 30℃ and 60℃. an inhibition activity against lipid peroxidation in hepatic microsomes of rats showed the highest at acetone faction extracted at acetone fraction among extracted fractions was shown to be the most potent antioxidative properties and this action was more potent in fractions extracted at 30℃ than those extracted at 60℃.

• Toxicological Research
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• 제7권1호
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• pp.1-12
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• 1991

The phenotyping of cytochrome P-450 in hepatic mivrosomes induced by phenytoin in the rats was carried out by using several monoclonal antibodies (MAbs) against specific P-450 isozymes. Phenytoin (180 mg/kg) was administered intrapritoneally for three consecutive days to the male Sprague-Dawley rats(100-120g). Solid phase radio-immunoassay showed higher binding affinity of MAb PB 2-66-3 and PCN 2-13-1 to the microsomes from phenytoin treated rats than those to from untreated rats, which was comparable to the level in phenobarbital induced rat hepatic microsomes.

• Journal of Ginseng Research
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• 제16권3호
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• pp.210-216
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• 1992

The effect of saponin extracted from Panax grneng CA Meyer on DNA repair and replicative DNA synthesis were examined in CHO-Kl cells cotreated with benzo(a)pyrene and rat liver S-15 fraction. The DNA strand breaks inititated by benzo(a)pyrene metabolites were measured by alkaline election technique. The addition of ginseng saponin to the culture media resulted in decrease of benzo(a)pyrene-induced DNA strand breaks, and restored the suppressed-semiconservative-DNA-synthesis by the carcinogen. DNA repair synthesis in the damaged cells was also elevated by the ginseng treatment when the repairing activites were measured for the (3H)-thymidine incorporation into the carcinogen damaged cellular DNk Comparative analysis of DNA-adduces of benzo(a)pyrene metabortes in microsomes suggested that ginseng saponin treatment in rats reduced the formation of electrophilic metabolites of benzo (a)-pyrene in the rat liver microsomes.

• Journal of Plant Biology
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• 제37권3호
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• pp.293-299
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• 1994

Developing rice endosperm cells display two morphologically distinct rough endoplasmic reticulum (ER) membranes, the cisternae ER (C-ER) and theprotein body ER (PB-ER), the latter delimiting the prolamine protein bodies. We (Li et al., 1993) have recently shown that the storage protein mRNAs are not randomly distributed on these ER types; the C-ER is enriched for glutelin mRNAs, whereas the PB-ER harbors predominantly prolamine transcripts. To address whether these ER types have differnet capacities to translate these mRNAs and translocate their proteins into the lumen, a microsomal fraction enriched in C-ER vesicles was prepared from devleoping rice seeds. When present in an in vitro translatin system, the microsomes were able to proteolytically remove the signal peptide and internalize both preproglutelin and preprolamine within the microsomal vesicles. Of the two species, preprolamine was more effectively translocated and processed. These results suggest that the C-ER has the capacity to recognize and bind both storage protein mRNAs during protein synthesis. Moreover, efficient translocation and processing of glutelin requires additional factors that are deficient or absent in the in vitro system.

• Journal of Pharmaceutical Investigation
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• 제41권3호
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• pp.143-146
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• 2011

Scutellariae Radix is widely used in the traditional herbal medicine for the treatment of fever, cough, dysentery, hepatitis and hypertension in Korea, China and Japan. In this study, we investigated the effects of 70% ethanolic extract of Scutellariae Radix (SRE) on CYP450-mediated drug metabolism in the in vitro systems using human liver microsomes and hepatocytes. The microsomal incubation assay showed that SRE inhibited the drug metabolism reactions catalyzed by CYP1A2, CYP2C8 and CYP2C9 in a dose-dependent manner. In particular, SRE was shown to strongly inhibit the metabolic activity of CYP1A2 with an $IC_{50}$ value of 4.6 ${\mu}g/mL$. When SRE was evaluated for its effect on the induction of CYP450 enzyme activities in cryopreserved human hepatocytes, SRE did not exhibit any effect.