• Mass Spectrometry Letters
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• 제14권3호
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• pp.116-119
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• 2023

Gynostemma pentaphyllum (Thunb.) Makino extract, a natural product with a history of traditional use, has gained attention for its potential health benefits. This study aimed to investigate its effects on key cytochrome P450 (CYP) enzymes using LC-MS/MS. Human liver microsomes and cDNA-expressed CYP2C8, CYP2C9, CYP2C19, and CYP3A4 supersomes were employed. Enzyme activity was assessed based on the formation of CYP-specific marker metabolites. The resulting data showed that the extract exhibited inhibitory effects on CYP2C8, CYP2C9, CYP2C19, and CYP3A4. Thus, G. pentaphyllum extract may influence the pharmacokinetics of drugs metabolized by CYP2C8, CYP2C9, CYP2C19, and CYP3A4. These findings emphasize the importance of considering potential herb-drug interactions when incorporating this extract into therapeutic regimens or dietary supplements.

• 한국환경성돌연변이발암원학회지
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• 제23권3호
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• pp.99-102
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• 2003

IARC classified areca quid as a human carcinogen. Areca quid chewed in Taiwan includes Piper betle inflorescence, which contains high concentrations of safrole (15 mg/fresh weight). Safrole is a documented rodent hepatocarcinogen, and chewing areca quid may contribute to human exposure (420 $\mu$m in saliva). The carcinogenicity of safrole is mediated through 1'-hydroxysafrole formation, followed by sulfonation to an unstable sulfate that reacts to form DNA adducts. Using human liver microsomes and Escherichia coli membranes expressing bicistronic human P450s, CYP2E1 and CYP2C9 were identified as the main P450s involved in the activation of safrole. We have demonstrated the presence of stable safrole-dGMP adducts in human oral tissues following areca quid chewing using $^{32}$ P-postlabeling and HPLC mass spectrometry methods. By studying 88 subjects with a known AQ chewing history and 161 matched controls, we have demonstrated that the presence of safrole-DNA adducts in peripheral blood cells was correlated to AQ chewing, and CYP2E1 seemed to play an important role in the modulation of safrole-DNA adduct formation. We have also shown that safrole can form stable safrole-DNA adducts as well as oxidative damages in rodent liver. However, the stable safrole-DNA adducts may represent a more significant initial lesion as compared to the rapidly repaired safrole-induced 8-hydroxy-2'-deoxyguanosine. This oxidative DNA damage is mediated through the formation of hydoryxchavicol, the major safrole metabolite in human urine. Hydroxychavicol may have gone through two-electron oxidation to the o-quinone; then via one-electron reduction to semiquinone radicals to generate oxidative DNA damage. However, these reactive metabolites can be efficiently conjugated by GSH. These data suggest that safrole may contribute to the initiation of oral carcinogenesis through safrole-DNA adduct and not oxidative DNA damage. In addition, CYP2E1 may modulate this adduct formation.

• 한국식품영양과학회지
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• 제33권2호
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• pp.255-261
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• 2004

뽕나무가루 첨가 배지에서 배양한 느타리버섯균사체 배양물의 조추출물이 자유라다칼로 유도한 linloeic acid의 산화를 대조구에 비해 75.9% 감소시켰고, mouse liver microsome산화에서도 NADPH/Fe$^{++}$ system에서 64.3% 감소시켰다. 이와 같은 효과는 조추출물로부터 용매분획한 분획물의 단독 효과보다 우수하였다. 상황 및 동충하초버섯균사체 배양물의 조추출물도 느타리 버섯균사체 배양물의 조추출물과 효과가 유사하였지만 다소 낮았다.

• BMB Reports
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• 제32권3호
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• pp.226-231
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• 1999

In vitro effects of acetone on cytochrome P450 (P450)-dependent benzo(a)pyrene (B(a)P) hydroxylation supported by cumene hydroperoxide (CuOOH) or NADPH/$O_2 $ systems were studied using 3-methylcholanthrene-pretreated rat liver microsomes. The maximal rate of B(a)P hydroxylation at constant concentration ($80\;{\mu}M)$ of the substrate was observed in the presence of $30\;{\mu}M$ CuOOH. However, at concentrations higher than $30\;{\mu}M$ CuOOH the hydroxylation rates were rapidly decreased. In contrast to CuOOH, at a concentration of $200\;{\mu}M$ NADPH, B(a)P hydroxylation rate reached a plateau. At concentrations higher than $200\;{\mu}M$ NADPH, the rates of substrate hydroxylation were maintained at the maximal rate with no inhibition. Acetone at 1% (v/v) enhanced both CuOOH- and NADPH/$O_2$-supported B(a)P hydroxylation at the optimal concentrations of the cofactors. At concentrations higher than 1% (v/v) acetone, substrate hydroxylation was sterero specific under the support of these two cofactors; it was strongly enhanced with $30\;{\mu}M$ CuOOH, but rather inhibited in the $200\;{\mu}M$> NADPH/$0_2 $ system. The lipid peroxidation rate induced during CuOOH-supported P450-dependent B(a)P hydroxylation was increased as CuOOH concentrations were increased. Acetone in the concentration range of 2.5~7.5%(v/v) inhibited lipid peroxidation during CuOOH supported B(a)P hydroxylation. The finding that CuOOH-supported B(a)P hydroxylation is greatly enhanced by acetone suggests that acetone may contribute more to the activation of oxygen (for the insertion of oxygen into the substrate) in the presence of CuOOH than with NADPH/$O_2$. Acetone may also contribute to the partial inhibition of destruction of microsomal membranes by lipid peroxidation.

• 한국식품위생안전성학회지
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• 제30권4호
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• pp.383-389
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• 2015

본 연구에서는 유도비만 쥐에서 발효 서목태의 항산화 효과를 연구하기 위하여 체중 175 g의 SD계 암컷 흰쥐 24마리를 대상으로 정상 군, 고지방식이 군, 발효 서목태 엑기스 급여 군, 발효 서목태 음료 급여 군으로 분류하여 54일간 사육하였다. in vitro 항산화 활성에서는 발효 서목태 엑기스가 높은 활성 및 함량을 나타냈다. in vivo 항산화 활성에서는 발효 서목태 섭취 군이 고지방식이 대조 군에 비해 CAT, SOD 활성은 높은 활성을 보였으며, MDA량은 감소 현상을 보였다. 이와 같은 결과를 통해 발효 서목태가 항산화 효소의 증가로 활성산소의 제거능을 향상시킬 뿐만 아니라, 생체 내 대사과정에서 생성된 과산화물로부터 생체 조직을 보호하여 손상된 간조직의 기능을 회복시킨 것으로 사료된다.

• Biomolecules & Therapeutics
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• 제23권2호
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• pp.201-206
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• 2015

Scutellaria baicalensis is one of the most widely used herbal medicines in East Asia. Because baicalein and baicalin are major components of this herb, it is important to understand the effects of these compounds on drug metabolizing enzymes, such as cytochrome P450 (CYP), for evaluating herb-drug interaction. The effects of baicalin and baicalein on activities of ethoxyresorufin O-deethylase (EROD), methoxyresorufin O-demethylase (MROD), benzyloxyresorufin O-debenzylase (BROD), p-nitrophenol hydroxylase and erythromycin N-demethylase were assessed in rat liver microsomes in the present study. In addition, the pharmacokinetics of caffeine and its three metabolites (i.e., paraxanthine, theobromine and theophylline) in baicalin-treated rats were compared with untreated control. As results, EROD, MROD and BROD activities were inhibited by both baicalin and baicalein. However, there were no significant differences in the pharmacokinetic parameters of oral caffeine and its three metabolites between control and baicalin-treated rats. When the plasma concentration of baicalin was determined, the maximum concentration of baicalin was below the estimated $IC_{50}$ values observed in vitro. In conclusion, baicalin had no effects on the pharmacokinetics of caffeine and its metabolites in vivo, following single oral administration in rats.

• 한국균학회지
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• 제29권1호
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• pp.67-71
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• 2001

민간약재로 사용되어지는 아카시재목 버섯(Fomitella fraxinea) 자실체의 에탄올 추출물로부터 ethyl acetate 추출, silica gel chromatography, preparative TLC 등의 방법으로 항산화 활성을 나타내는 steroid계 화합물, F-1을 분리 정제하였다. EI-Mass, FT-IR, $^1H$ 및 $^{13}C$ NMR 등 기기 분석에 의하여 F-1은 분자량이 412.65, 분자식이 $C_{28}H_{44}O_2$의 steroid 화합물, ergosta-7,22-diene-3-one-$16{\beta}-ol$임을 확인하였다. F-1의 지질과산화 저해활성은 $10^{\mu}g/ml$의 농도에서 86%의 지질과산화 저해활성을 나타내었으며, $IC_{50}$ 값은 $3.8{\mu}g/ml$이었다. 이 화합물은 항산화제인 ${\alpha}-tocoperol$과 유사한 항산화 활성을 나타내었다.

• Journal of Nutrition and Health
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• 제36권4호
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• pp.376-381
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• 2003

본 연구에서는 흰쥐 간장에 있어서 아실-CoA 합성효소 4의 세포내 소기관의 존재 여부를 확인함과 동시에 fasting, high fat diet, fat-free high sucrose diet, 퍼옥시솜 증식 인자인 DEHP [Di-(2-ethylhexyl)phthalate]를 급여한 흰쥐 간장에 있어서 ACS4의 발현에 대하여 조사하였다. ACS4는 ACSI과 마찬가지로 흰쥐 간장의 마이크로솜, 미토콘드리아와 퍼옥시솜에 존재하는 것으로 생각되며 미토콘드리아에서 가장 많은 단백질이 검출되었다. ACS4 mRNA는 절식하였을 때와 high fat diet, fat-free high sucrose diet을 급여하였을 때는 대조군에 비하여 2.3배 발현이 증가하였으며 DEHP을 급여하였을 때는 3.9배 mRNA의 증가를 나타내었다. 이러한 결과를 종합하여 보면 간장에 있어서 ACS4는 기본적인 $\beta$-산화뿐만 아니라 호르몬에 의한 조절과 간접적으로는 인슐린에 의한 조절도 받는 것으로 생각되며 다양한 기능을 수행하고 있음을 추측할 수 있다.

• Biomolecules & Therapeutics
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• 제22권2호
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• pp.155-160
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• 2014

Thelephoric acid is an antioxidant produced by the hydrolysis of polyozellin, which is isolated from Polyozellus multiplex. In the present study, the inhibitory effects of polyozellin and thelephoric acid on 9 cytochrome P450 (CYP) family members (CYP1A2, CYP2A6, CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6, CYP2E1, and CYP3A4) were examined in pooled human liver microsomes (HLMs) using a cocktail probe assay. Polyozellin exhibited weak inhibitory effects on the activities of all 9 CYPs examined, whereas thelephoric acid exhibited dose- and time-dependent inhibition of all 9 CYP isoforms ($IC_{50}$ values, $3.2-33.7{\mu}M$). Dixon plots of CYP inhibition indicated that thelephoric acid was a competitive inhibitor of CYP1A2 and CYP3A4. In contrast, thelephoric acid was a noncompetitive inhibitor of CYP2D6. Our findings indicate that thelephoric acid may be a novel, non-specific CYP inhibitor, suggesting that it could replace SKF-525A in inhibitory studies designed to investigate the effects of CYP enzymes on the metabolism of given compounds.

• Toxicological Research
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• 제17권
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• pp.127-133
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• 2001

Together with cytochrome P450 (CYP), flavin-containing monooxygenase (FMO) present in liver microsomes oxidizes various endogenous and exogenous chemicals. In an effort to determine the human FMO activity, we have developed two non-invasive urine analysis methods using caffeine (CA) and ranitidine (RA) as the probe compounds. As the production of theobromine (TB) and ranitidine N-oxide (RANO) from CA and RA is catalyzed primarily by the hepatic FMO, we have assigned the urinary molar ratios of TB/CA and RA/RANO as the in vivo FMO activity. In 200 age-matched Korean volunteers, the obtained TB/CA ratio ranged from 0.4 to 15.2 (38-fold difference) and the RA/RANO ratio from 5.7 to 27.2 (4.8-fold). The FMO activity of 20's, determined by caffeine metabolism, was the highest (2.5$\pm$l.9) and those of 30's, 40's, 50's, 60's and 70's were 40%, 50%, 24%, 39% and 36% of the 20's, respectively. Intake of grapefruit juice, known to contain flavonoids, inhibited the in vivo FMO (TB/CA) activity by 79%. Addition of the flavonoids like naringin, quercitrin and kaempferol, present in grapefruit juice, to the in vitro microso-mal FMO assay, thiobenzamide S-oxidation, produced 75%, 70% and 60% inhibition, respectively. Obtained Ki values of quercitrin, kaempferol and naringin on the in vitro FMO activity were 6.2, 12.0 and 13.9 $\mu\textrm{M}$, respectively. This suggested that the dose of drug should need to be adjusted to suit the individual FMO activities when the drugs metabolized by FMO are given to patients. As the intake of grapefruit juice has been identified to inhibit the FMO as well as CYP3A4 and lA2 activities, patients taking drugs metabolized by these enzymes should not drink grapefruit juice as the carrier.