• Biomolecules & Therapeutics
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• 제17권4호
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• pp.455-460
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• 2009

Foods of plant origin, especially fruits and vegetables, have attracted attention because of their potential benefits to human health. In this report, Rubi Fructus (RF), the dried unripe fruit of Rubus coreanus Miq (Rosaceae) and ellagic acid (EA) purified from RF were used to test their potential hepatoprotective effect against acetaminophen (AAP)-induced hepatotoxicity in rats. RF extract (RFext) and EA reduced the elevated levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST) in serum and the content of lipid peroxide in liver by AAP administration, while the increment of the cellular glutathione (GSH) content and the induction of glutathione S-transferase (GST) and glutathione peroxidase (GSH-PX) which were decreased by AAP administration. RFext and EA from RFext did not affect the two major form of cytochrome P450s, cytochrome P450 2E1 (CYP2E1) and cytochrome P450 1A2 (CYP1A2), but downregulated the cytochrome P450 3A4 (CYP3A4) related to the conversion of AAP to N-acetyl-P-benzoquinone imine (NAPQI). These results suggest that RFext and EA from RF exhibit a hepatoprotective effect not only by increasing antioxidant activities but also by down-regulating CYP3A4 in the AAP-intoxicated rat.

• Mass Spectrometry Letters
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• 제4권2호
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• pp.34-37
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• 2013

Honokiol and magnolol, the major bioactive neolignans of magnolia officinalis, are the most important constituents of the crude drug prescriptions that are used in the therapy of neuroses and various nervous disorders. There have been limited reports on the effects of neolignoid compounds on human cytochrome P450 activity. Therefore, the inhibitory effects of honokiol and magnolol on seven human cytochrome P450 s were evaluated in human liver microsomes. Honokiol and magnolol showed the most potent inhibition of CYP1A2-mediated phenacetin O-deethylase activity ($IC_{50}$ values of 3.5 and 5.4 mM, respectively) among the seven P450s tested. These in vitro data indicate that neolignan compounds can inhibit the activity of CYP1A2 and suggest that these compounds should be examined for potential pharmacokinetic drug interactions in vivo.

• 한국응용곤충학회지
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• 제32권3호
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• pp.291-299
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• 1993

네가지 종류의 곤충 중장에 있는 주요 해독효소인 cytochrome P-450 monooxygenases의 활성을 그들의 먹이종류 및 섭식여부와 연관시켜 분석하였다. 담배나방유충을 인공사료로 사육하였을 때 전반적으로 중장의 cytochrome P-450 monooxygtenases(MFO)활성이 지방체의 경우보다 3배가량 높게 나타났다. 고추열매나 인공사료를 공급하여 사육하였을 때보다 담배잎으로 사육하였을 때 담배나방유충의 중장 MFO는 훨씬 높게 나타났으며, 흰불나방의 경우염주나무잎이 MFO활성을 가장 높게 유기했다. 담배나방, 파밤나방, 희불나방, 담배거세미나방 등의 유충들을 각각의 인공사료로 사육하였을 때 광식성이며 동시에 살충제저항성을 보유하고 있는 파밤나방의 MFO활성이 가장 높게 나타났다.

• 한국독성학회:학술대회논문집
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• 한국독성학회 2001년도 International Symposium on Signal transduction in Toxicology
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• pp.143-143
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• 2001

Human cytochrome P450 (CYP or P450) 3A4 (CYP3A4) is the most abundant among P450s in human liver. We previously reported that the expression of CYP3A4 in membranes prepared from E. coli coexpressed the bicistronic construct of CYP3A4 and NADPH-P450 reductase with cytochrome b$_{*}$ (b5) was showed 20-60% higher than that in membranes from E. coli expressed only the bicistronic construct with culturing longer times (48-72h).(omitted)

• BMB Reports
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• 제38권3호
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• pp.366-369
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• 2005

NADPH-cytochrome P450 reductase (CPR) transfers electrons from NADPH to cytochrome P450 and also catalyzes the one-electron reduction of many drugs and foreign compounds. Various spectrophotometric assays have been performed to examine electron-accepting properties of CPR and its ability to reduce cytochrome $b_5$, cytochrome c, and ferricyanide. In this report, reduction of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) by CPR has been assessed as a method for monitoring CPR activity. The principle advantage of this substance is that the reduction of MTT can be assayed directly in the reaction medium by a continuous spectrophotometric method. The electrons released from NADPH by CPR were transferred to MTT. MTT reduction activity was then assessed spectrophotometrically by measuring the increase of $A_{610}$. MTT reduction followed classical Michaelis-Menten kinetics ($K_m\;=\;20\;{\mu}M$, $k_{cat}\;=\;1,910\;min^{-1}$). This method offers the advantages of a commercially available substrate and short analysis time by a simple measurement of enzymatic activity of CPR.

• Environmental Analysis Health and Toxicology
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• 제17권4호
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• pp.307-314
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• 2002

Effects of ($\pm$)-camphor on liver cytochrome P450 enzymes were investigated in male ICR mice. Mice were treated intraperitoneally with 0, 200, 400 and 800 mg/kg of ($\pm$)-camphor in corn oil for 3 consecutive days. Twenty four hr after the final treatment, the animals were subjected to necropsy. The activities of serum aspartate aminotransferase and serum alanine aminotransferase were slightly changed by the treatment with ($\pm$)-camphor at the doses used. Administration of ($\pm$)-camphor to mice significantly induced the hepatic activities of pentoxyresorufin O-depentylase and benzyloxyresorufin O-debenzylase and weakly induced ethoxyresorufin O-deethylase in dose-dependent manners. The present results suggested that ($\pm$)-camphor might act as a relatively specific inducer of hepatic cytochrome P450 2B in male ICR mice.

• 한국식품위생안전성학회지
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• 제11권4호
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• pp.291-297
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• 1996

The role of cytochrome P-450 2E1 (P450 2E1) in the early phase of alcoholic fatty liver was examined. Female rats were pretreated with either allyl sulfide (200 mg/kg, po), disulfiram (500 mg/kg, po), YH 439 (250 mg/kg, po) or pyrazine (200 mg/kg/day$\times$2 days, ip). Marked changes in carbon tetrachloride-induced hepatotoxicity and caboxyhemoglobin (COHb) elevation due to dichloromethane administration were observed in rats treated with one of the P450 2E1 modulators. A single dose of ethanol (6 g/kg, po) increased the hepatic triglyceride contents approximately 2 fold, which was inhibited completely by YH 439 pretreatment. However, the other P450 2E1 modulators failed to alter the ethanol-induced hepatic triglyceride accumulation. In vitro hepatic microsomal enzyme activity was determined in 4 week old premature and 12 week old adult rats. Aminopyrine-N demethylation was not different, but p-nitrophenol hydroxylation and p-nitroanisole O-demethylation were significantly higher in premature rats. However, no difference in the triglyceride accumulation induced by an intraperitoneal dose of ethanol (3 g/kg) was noted between premature and adult rats. The results suggest that the P450 2E1 activity dose not play an important role in the induction of acute alcoholic fatty liver.

• 한국식품영양과학회지
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• 제24권6호
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• pp.859-866
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• 1995

본 연구에서는 액체식이로 알코올을 열량의 35%로 6주간 섭취시킨 흰주의 간조직내 지질과산화물과 glutathione 이용효소계의 활성도 및 cytochrome P-450에 미치는 영향을 살펴보고 아울러 간암의 발암원으로 알려진 2-AAF를 투여하여 이들의 상호효과를 조사한 결과 다음과 같은 결과를 얻었다. 1. 체중, 간무게, 그리고 체중에 대한 간무게의 알코올에 대한 효과는 유의적인 차이를 보여 체중은 알코올에 대한 효과는 유의적인 차이를 보여 체중은 알코올 섭취군이 유의적으로 감소하였고 간무게 및 체중에 대한 간무게는 알코올군의 유의적으로 증가하였다. 2. Microsome의 지질과산화물 함량 및 cytosol의 glutathione peroxidase, glutathione reductase 활성도는 알코올과 2-AAF 투여시 모두 유의적인 차이를 보이지 않았으나, cytosol의 glutathione S-transferase 활성도는 알코올과 2-AAF에 의해서 모두 유의적으로 증가하였고 알코올 섭추와 함께 투여시 GST 활성도가 가장 많이 증가하였다. 3. Microsome의 cytochrome P-450 및 cytochrome b5 함량에 대한 알코올 효과는 cytochrome P-450 함량을 증가시키는 경향이 있고 cytochrome b5는 유의적인 증가를 보여 주었으며 2-AAF 투여 역시 cytochrome P-450의 유의적인 증가를 유도하였다. 따라서 알코올 섭취와 2-AAF 함께 투여 시 cytochrome P-450의 함량이 대조군의 약 2.2배 정도 증가하였으며 cytochrome b5 함량이 1.7배로 높이 증가하였다. 이는 2-AAF가 cytochrome P-450을 유도하여 자신의 대사를 촉진시키며 알코올의 섭취 또한 2-AAF의 hydroxylation을 증가시킬 수 있는 것으로 생각된다. 이상의 결과에서 과량의 알코올을 만성적으로 섭취시 간조직내의 microsome의 MFO system에 영향을 미쳐서 발암물질의 생체 활성화를 촉진시킬 수 있고 또한 GST의 활성도를 증가시키므로 어느 정도 발암과정에 영향을 미치는 것으로 생각된다.

• 한국환경보건학회지
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• 제19권3호
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• pp.58-63
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• 1993

In order to elucidate the alteration of drug-metabolizing enzymes and mechanism in the animal with hepatic injury and ketosis, the regulation of P450IIE was studied in the rats with heaptic injury caused by CCl$_4$ and with ketosis caused by streptozotocin and high-fat diet. P450IIE expression in liver was examined by the combination of enzyme activities, Western immunoblot, and mRNA Northern blot analyses using specific polyclonal antibody and cDNA probe for P450IIE. Enzyme activity and amounts of immunoreactive P450IIE were rapidly decreased in a time-dependent manner after a single dose of CCl$_4$ . However, the decreases in P450IIE enzyme activity and immunoreactive protein by CCl$_4$ were not accompanied by a decline in its mRNA level. The data thus suggested a post-translational reduction of P450IIE by CCl$_4$. The enzyme activities (aniline hydroxylase) in hepatic microsomes were elevated about 2-3-fold by streptozotocin and feeding with a high fat diet. This increases in enzyme activities were also accompanied by 3-fold increases in immunoreactive P450IIE protein and its mRNA. Our data thus indicated that P450IIE induction during the ketosis appears to be due to pretranslational activation.

• 동의생리병리학회지
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• 제21권6호
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• pp.1534-1542
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• 2007

In this study, the liver protective effect of the hot water extracts of Scutellaria radix (SR) was investigated. The SR exhibited a hepatoprotective activity against $CCl_4$-induced liver damage in Sprague-Dawley (SD) rats and Chang cell. And the SR also showed significant decrease of malodialdehyde (MDA) and increase of glutathion (GSH), catalase activity in rat liver homogenate. The expression of cytochrome P450 2E1 (CYP2E1), measured by RT-PCR and western blot, was significantly decreased in the SR treated SD rats and Chang cell. But $CCl_4$ and SR has no significant effect on 1A1 and 3A1 isoform of cytochrome P450. Based on these findings, it is suggested that hepatoprotective effects of SR possibly related to antioxidative effects and downregulation of CYP2E1 expression.