• Korean Journal of Pharmacognosy
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• v.21 no.1
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• pp.74-82
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• 1990

The effects of naturally occurring furanocoumarins on cytochrome P-450 have been investigated in rat liver microsomes. Incubation of microsomes with an NADPH-generating system and four furanocoumarins such as imperatorin, isoimperatorin, phellopterin and byakangelicin at $37^{\circ}$ in vitro resulted in a significant destruction of cytochrome P-450. A single treatment(50 mg/kg, i.p.) of rats with each furanocoumarin caused a rapid loss of cytochrome P-450 accompanied by the loss of heme from the microsomes but not by the loss of cytochrome $b_5$. It is suggested that cytochrome P-450 is specifically destroyed by furanocoumarins in a metabolic process involving destruction of its heme group and as a consequence, hepatic enzyme activities are depressed markedly.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1994.11a
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• pp.127-133
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• 1994

• The Journal of Korean Medicine
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• v.29 no.4
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• pp.104-113
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• 2008

Objectives: The aim of this study was to investigate the influence of five herbal medicines on cytochrome P450 (CYP) 3A4 drug-metabolizing enzymes in human liver microsomes. Methods: By using of human liver microsomes, we extracted Cnidium officinale Makino, Rhus verniciflua Stokes, Prunus persica Batsch, Corydalis remota Fisch, Carthamus tinctorius Linne, which are called Hwalhyulgeoouhyak(活血祛瘀藥). Then they were incubated and measured for relative enzyme activity under incubation conditions compared to ketoconazole, which is known as a representative inhibitor of CYP 3A4. Results: We showed that all of five traditional herbal medicines had no inhibition effect of CYP 3A4 at 10, 20, 30, 40, and 50${\mu}g/m{\ell}$ doses in human liver microsomes, although Rhus verniciflua Stokes (RVS) showed a little inhibition as about 95% enzyme activity of control. However, this result was not enough to prove that RVS has a CYP 3A4 inhibition effect. Moreover, we can't confirm that those rates have significant induction effect on CYP 3A4. Conclusions: The result of this study could support that those herbal medicines are more reliable than chemical drugs, even if this is a basic step to prove that result.

• Archives of Pharmacal Research
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• v.26 no.8
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• pp.631-637
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• 2003

Chloroquine has been used for many decades in the prophylaxis and treatment of malaria. It is metabolized in humans through the N-dealkylation pathway, to desethylchloroquine (DCQ) and bisdesethylchloroquine (BDCQ), by cytochrome P450 (CYP). However, until recently, no data are available on the metabolic pathway of chloroquine. Therefore, the metabolic pathway of chloroquine was evaluated using human liver microsomes and cDNA-expressed CYPs. Chloroquine is mainly metabolized to DCQ, and its Eadie-Hofstee plots were biphasic, indicating the involvement of multiple enzymes, with apparent $K_m and V_{max}$ values of 0.21 mM and 1.02 nmol/min/mg protein 3.43 mM and 10.47 nmol/min/mg protein for high and low affinity components, respectively. Of the cDNA-expressing CYPs examined, CYP1A2, 2C8, 2C19, 2D6 and 3A4/5 exhibited significant DCQ formation. A study using chemical inhibitors showed only quercetin (a CYP2C8 inhibitor) and ketoconazole (a CYP3A4/5 inhibitor) inhibited the DCQ formation. In addition, the DCQ formation significantly correlated with the CYP3A4/5-catalyzed midazolam 1-hydroxylation (r=0.868) and CYP2C8-catalyzed paclitaxel 6$\alpha$-hydroxylation (r = 0.900). In conclusion, the results of the present study demonstrated that CYP2C8 and CYP3A4/5 are the major enzymes responsible for the chloroquine N-deethylation to DCQ in human liver microsomes.

• Archives of Pharmacal Research
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• v.29 no.11
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• pp.984-989
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• 2006

1-Furan-2-yl-3-pyridin-2-yl-propenone (FPP-3) has been characterized to have an anti-inflammatory activity through the inhibition of the production of nitric oxide and tumor necrosis $factor-{\alpha}$. In the present studies, the phase 1 metabolism of FPP-3 was investigated in rat liver microsomes and cytosols. When FPP-3 was incubated with rat liver microsomes and cytosols in the presence of NADPH. 2 major peaks were detected on a liquid chromatography/electrospray ionization-mass spectrometry. Two metabolites (i.e., M1 and M2) were characterized as reduced forms on propenone: M1 (1-furan-2-yl-3-pyridin-2-yl-propan-1-one) was the initial metabolite and M2 (1-furan-2-yl-3-pyridin-2-yl-propan-1-ol) was a secondary alcohol believed to be formed from M1.

• Archives of Pharmacal Research
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• v.16 no.2
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• pp.89-93
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• 1993

Incubation of $S(-)-^3H$-nicotine with rabbit lung microsomes in the presence of dioxygen and NADPH results in the formation of metabolities that bind covalently to microsomal macro-molecules. The addition of cytochrome P-450 monooxygenase inhibitors, $\alpha$-methylbenzyl ami-nobenzotriazole and aroclor 1260, inhibited both (S)-nicotine metabolism and covalent binding. The relative rates of oxidation of nicotine $\Delta^{1',5'}$ iminium ion to continine indicates that lung $100,000\times{g}$ supematant catalyzed this oxidation approximately 18 times slower than that of liver system based on mg of protein, and increased covalent interactions. Since than that of liver system based on mg of protein, nd increased covalent interactions. Since the activity of lung iminium oxidase appears much lowr than the liver, it is tempting to speculate that localized concentrations of nicotine $\Delta^{1',5'}$ iminium ion in the lung will survive for a longer period of time. These results support that cytochrome P-450 catalyzed oxidation of nicotine leads to the formation of reactive nad electrophilic intemediates capable of chemical interactions with biomacromolecules.

• Mass Spectrometry Letters
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• v.13 no.4
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• pp.152-157
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• 2022

Schisandra chinensis and its fruits have been used as a traditional herbal medicine to treat liver dysfunction, fatigue, and chronic coughs. Several in vitro and in vivo studies suggested that dibenzocyclooctadiene lignans present in Schisandra fruits strongly inhibit CYP3A4 activity. However, reports on the inhibitory potential of dietary Schisandra supplements against CYP3A activity are limited despite their increasing consumption as dietary supplements. In this study, we evaluated the CYP3A-inhibitory potential of four dietary Schisandra supplements in human liver microsomes. At a concentration of 0.05 mg/mL, Schisandra supplements from Nature's Way, Swanson, Planetary Herbals, and Only Natural inhibited CYP3A activity by 93.9, 70.8, 33.6, and 24.8%, respectively. Nature's Way, which exhibited the strongest inhibition against CYP3A, had the highest contents of gomisin B and gomisin C, which potently inhibit CYP3A activity. The in vivo pharmacokinetics of this product should be examined to determine whether the clinical relevance of inhibiting CYP3A activity by dietary Schisandra supplementation.

• Archives of Pharmacal Research
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• v.28 no.11
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• pp.1287-1292
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• 2005

KR-33028 (N-[4-cyano-benzo[b]thiophene-2-carbonyl]guanidine) is a new cardioprotective agent for preventing ischemia-reperfusion injury. This study was performed to identify the metabolic pathway of KR-33028 in human liver microsomes and to compare its metabolism with that of cryopreserved human hepatocytes. Human liver microsomal incubation of KR-33028 in the presence of NADPH and UDPGA resulted in the formation of four metabolites, M1, M2, M3, and M4. M1 and M2 were identified as 5-hydroxy-KR-33028 and 7-hydroxy-KR-33028, respectively, on the basis of LC/MS/MS analysis with the synthesized authentic standard. M3 and M4 were suggested to be dihydroxy-KR-33028 and hydroxy-KR-33028-glucuronide, respectively. Metabolism of KR-33028 in cryopreserved human hepatocytes resulted in the formation of M1, M2, and M4. These data show a good correlation between major metabolites formed in human liver microsomes and cryopreserved human hepatocytes. In addition, KR­33028 was found to inhibit moderately the metabolism of CYP1A2 substrates. Based on the results obtained metabolic pathway of KR-33028 is proposed.

• Journal of Life Science
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• v.9 no.4
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• pp.466-472
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• 1999

These studies were designed to investigate the effects of pine (Pinus densiflora Sieb et Zucc.) needle extract (PNE) on oxygen radicals and their scavenger enzymes in liver membranes of Sprague-Dawley (SD) rats as a study on investigation of anti-aging effect and determination of chemical structures of PNE through the animal experiments. Male SD rats were fed basic diets (control group) and experimental diets (0.5% and 1.0%-PNE group) for 6 weeks. There were no significant differences in hydroxyl radical (·OH) formations of liver mitochondria and microsomes in 0.5%-PNE group, while ·OH formations were significantly decreased (10% and 18%, respectively) in liver mitochondria and microsomes of 1.0%-PNE group compared with control group. Microsomal hydrogen peroxides and cytosolic superoxide radicals were remarkably decreased (20% and 20∼25%, respectively) in 0.5% and 1.0%-PNE groups compared with control group. Mn-SOD activities in mitochondria were significantly increased about 10% in 1.0%-PNE group, while Mn-SOD activities in mocrosomes were remarkably increased (16∼20%) in 0.5% and 1.0%-PNE groups compared with control group. There were no significant differences in Cu, Zn-SOD activities of liver cytosol in 0.5% and 1.0%-PNE groups, while glutathione peroxidase (GSHPx) and catalase (CAT) activities were significantly decreased (28∼30% and 15∼30%, respectively) in liver cytosols of 0.5% and 1.0%-PNE groups compared with control group. These results suggest that these PNE may play a effective role in a attenuating a oxygen radical formations and increasing a scavenger enzyme activities.

• BMB Reports
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• v.40 no.6
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• pp.1039-1049
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• 2007

Overdoses of acetaminophen cause hepato-renal oxidative stress. The present study was undertaken to investigate the protective effect of a 43 kDa protein isolated from the herb Cajanus indicus, against acetaminophen-induced hepatic and renal toxicity. Male albino mice were treated with the protein for 4 days (intraperitoneally, 2 mg/kg body wt) prior or post to oral administration of acetaminophen (300 mg/kg body wt) for 2 days. Levels of different marker enzymes (namely, glutamate pyruvate transaminase and alkaline phosphatase), creatinine and blood urea nitrogen were measured in the experimental sera. Intracellular reactive oxygen species production and total antioxidant activity were also determined from acetaminophen and protein treated hepatocytes. Indices of different antioxidant enzymes (namely, superoxide dismutase, catalase, glutathione-S-transferase) as well as lipid peroxidation end-products and glutathione were determined in both liver and kidney homogenates. In addition, Cytochrome P450 activity was also measured from liver microsomes. Finally, histopathological studies were performed from liver sections of control, acetaminophen-treated and protein pre- and post-treated (along with acetaminophen) mice. Administration of acetaminophen increased all the serum markers and creatinine levels in mice sera along with the enhancement of hepatic and renal lipid peroxidation. Besides, application of acetaminophen to hepatocytes increased reactive oxygen species production and reduced the total antioxidant activity of the treated hepatocytes. It also reduced the levels of antioxidant enzymes and cellular reserves of glutathione in liver and kidney. In addition, acetaminophen enhanced the cytochrome P450 activity of liver microsomes. Treatment with the protein significantly reversed these changes to almost normal. Apart from these, histopathological changes also revealed the protective nature of the protein against acetaminophen induced necrotic damage of the liver tissues. Results suggest that the protein protects hepatic and renal tissues against oxidative damages and could be used as an effective protector against acetaminophen induced hepato-nephrotoxicity.