• Bulletin of the Korean Chemical Society
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• 제24권5호
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• pp.559-565
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• 2003

An analytical method the determination of benzo(a)pyrene (BaP) and its hydroxylated metabolites, 1-hydroxybenzo(a)pyrene (1-OHBaP), 3-hydroxybenzo(a)pyrene (3-OHBaP), benzo(a)pyrene-4,5-dihydrodiol (4,5-diolBaP) and benzo(a)pyrene-7,8-dihydrodiol (7,8-diolBaP), in rat urine and plasma has been developed by HPLC/FLD and GC/MS. The derivatization with alkyl iodide was employed to improve the resolution and the detection of two mono hydroxylated metabolites, 1-OHBaP and 3-OHBaP, in LC and GC. BaP and its four metabolites in spiked urine were successfully separated by gradient elution on reverse phase ODS $C_{18}$ column (4.6 mm I.D., 100 mm length, particle size 5 ㎛) using a binary mixture of MeOH/H₂O (85/15, v/v) as mobile phase after ethylation at 90 ℃ for 10 min. The extraction recoveries of BaP and its metabolites in spiked samples with liquid-liquid extraction, which was better than solid phase extraction, were in the range of 90.3- 101.6% in n-hexane for urine and 95.7-106.3% in acetone for plasma, respectively. The calibration curves has shown good linearity with the correlation coefficients (R²) varying from 0.992 to 1.000 for urine and from 0.996 to 1.000 for plasma, respectively. The detection limits of all analytes were obtained in the range of 0.01-0.1 ng/mL for urine and 0.1-0.4 ng/mL for plasma, respectively. The metabolites of BaP were excreted as mono hydroxy and dihydrodiol forms after intraperitoneal injection of 20 mg/kg of BaP to rats. The total amounts of BaP and four metabolites excreted in dosed rat urine were 3.79 ng over the 0-96 hr period from adminstration and the excretional recovery was less than 0.065% of the injection amounts of BaP. The proposed method was successfully applied to the determination of BaP and its hydroxylated metabolites in rat urine and plasma for the pharmacokinetic studies.

• Archives of Pharmacal Research
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• 제7권1호
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• pp.65-68
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• 1984

Mechanism of the monoamine oxidase inhibition by tranylcypromine was studied in relation to its metabolism to reactive apecies. A metabolic study performed to collect general biotransformation pathway in rats provided GC/MS evidence for the detection of two new metabolites, N-acetyl and hydroxylated N-acetyltranylacypromine.

• Mass Spectrometry Letters
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• 제7권3호
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• pp.69-73
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• 2016

High-resolution quadrupole-Orbitrap mass spectrometry (HRMS), with high-resolution (> 10,000 at full-width at half-maximum) and accurate mass (< 5 ppm deviation) capabilities, plays an important role in the structural elucidation of drug metabolites in the pharmaceutical industry. ML106, a derivative of imidazobenzimidazole, decreased melanin content and tyrosinase activity in a dose-dependent manner. Here, we investigated the phase 1 metabolic pathway of ML106 using HRMS in human liver microsomes (HLMs) and recombinant cDNA-expressed cytochrome P450 (CYP). After the incubation of ML106 with pooled HLMs and recombinant cDNA-expressed CYP in the presence of NADPH, five phase 1 metabolites, including three mono-hydroxylated metabolites (M1-3) and two di-hydroxylated metabolites (M4 and M5), were investigated. The metabolite structures were postulated by the elucidation of protonated mass spectra using HRMS. The CYP isoforms related to the hydroxylation of ML106 were studied after incubation with recombinant cDNA-expressed CYP. Here, we identified the phase 1 metabolic pathway of ML106 induced by CYP in HLMs.

• 한국환경보건학회지
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• 제37권6호
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• pp.474-481
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• 2011

This study investigated urinary metabolites of polycyclic aromatic hydrocarbons (PAHs) in the urine of smokers and non-smokers by liquid chromatography triple quordrupole tandem mass spectroscopy (LC/MS/MS). Compounds analyzed for urinary biomarkers of PAHs were five mono-hydroxylated PAHs metabolites; 1-naphthol, 2-naphthol, 1-hydroxypyrene(1-OHP), 3-phenanthrol, 2-fluorenol. Urine samples were pretreated by enzymatic hydrolysis and solid phase extraction method. Smokers were composed of 17 men and five women; non-smokers 17 men and 16 women. Smoking increased urinary concentrations of five PAHs metabolites significantly higher than those of nonsmokers. Statistically significant correlations among the five PAHs metabolites were shown. The results suggest that LC/MS/MS technology should be useful in the environmental health discipline.

• Journal of Microbiology and Biotechnology
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• 제34권3호
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• pp.725-734
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• 2024

CYP102A1 from Bacillus megaterium is an important enzyme in biotechnology, because engineered CYP102A1 enzymes can react with diverse substrates and produce human cytochrome P450-like metabolites. Therefore, CYP102A1 can be applied to drug metabolite production. Terpinen-4-ol is a cyclic monoterpene and the primary component of essential tea tree oil. Terpinen-4-ol was known for therapeutic effects, including antibacterial, antifungal, antiviral, and anti-inflammatory. Because terpenes are natural compounds, examining novel terpenes and investigating the therapeutic effects of terpenes represent responses to social demands for eco-friendly compounds. In this study, we investigated the catalytic activity of engineered CYP102A1 on terpinen-4-ol. Among CYP102A1 mutants tested here, the R47L/F81I/F87V/E143G/L188Q/N213S/E267V mutant showed the highest activity to terpinen-4-ol. Two major metabolites of terpinen-4-ol were generated by engineered CYP102A1. Characterization of major metabolites was confirmed by liquid chromatography-mass spectrometry (LC-MS), gas chromatography-MS, and nuclear magnetic resonance spectroscopy (NMR). Based on the LC-MS results, the difference in mass-to-charge ratio of an ion (m/z) between terpinen-4-ol and its major metabolites was 16. One major metabolite was defined as 1,4-dihydroxyp-menth-2-ene by NMR. Given these results, we speculate that another major metabolite is also a mono-hydroxylated product. Taken together, we suggest that CYP102A1 can be applied to make novel terpene derivatives.

• Bulletin of the Korean Chemical Society
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• 제19권2호
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• pp.194-196
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• 1998

The metabolism of dromostanolone (2α-methyl-5α- androstan-17β-ol-3-one) was studied in three adult volunteers after oral dose of 20 mg. Solvent extracts of urine obtained after enzyme hydrolysis were derivatized with MSTFA/TMCS and MSTFA/TMIS. The structures of intact drug and its metabolites were determined by gas chromatography/mass spectrometry (GC/MS) in electron impact (EI) mode. The major metabolite (2α-methyl-5α- androstan-3α-ol-17-one), its 3β-epimer, parent compound, and several hydroxylated metabolites including intact drug were detected by comparing total ion chromatograms of control urine with that of the administered sample. Two epimers of 2α-methyl-5α- androstan-3,17β-diol were detected using selected ion monitoring. The maximum excretion of dromostanolone and 2α-methyl-5α- androstan-3α-ol-17-one was reached in 6.2-15 hr. The half-life of intact dromostanolone was 5.3 hr. About 3.0% of the administered amount was found to be excreted within 95 hr as unchanged form.

• Toxicological Research
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• 제27권1호
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• pp.15-18
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• 2011

The toxicities of phenanthrene (PH) and pyrene (PY) are less than benzo(a)pyrene (BaP), but both compounds are found in higher concentrations in the air, feed, and food. Most PAHs are metabolized to hydroxylated compounds by the hepatic cytochrome P450 monooxigenases system. Metabolites are excreted into urine and feces. We determined concentrations of PH, PY and BaP in muscle and hydroxylated metabolites, 3-OH-PH, 1-OH-PY, and 3-OH-BaP, respectively, in urine from dairy cattle (n = 24). We also evaluated the relationship between parent compounds in muscle and their metabolites in urine. Concentrations of PH and PY in muscle ranged from 0.7~4.8 ng/g ($1.8{\pm}1.7$) and 0.4~4.1 ng/g ($1.2{\pm}1.2$), respectively. Concentrations of 3-OH-PH and 1-OH-PY in urine ranged from 0.1~5.9 ng/ml ($2.9{\pm}3.7$) and 0.5~3.6 ng/ml ($1.9{\pm}2.3$), respectively. Correlation coefficient for PY concentration in muscle versus 1-OH-PY in urine was 0.657 and for PH concentration in muscle versus 3-OH-PH in urine was 0.579. Coefficient determination for PY and PH concentrations in muscle was 0.886 and for 1-OH-PY and 3-OH-PH in urine was 0.834. This study suggests that 1-OH-PY and 3-OH-PH could be used as biomarkers for PAHs exposure in dairy cattle.

• Archives of Pharmacal Research
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• 제26권8호
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• pp.606-611
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• 2003

Byakangelicin, 9-(2,3-dihydroxy-2-methylbutoxy)-4-methoxy-7H- furo[3,2-g][l]benzopyran-7-one (BKG), a component of Angelicae dahuricae Radix, is considered to be an inhibitor of aldose reductase for the treatment of diabetic cataract. An analytical method for the isolation of BKG developed by high-performance liquid chromatography has been reported. No literature on the metabolism of BKG, however, has been found. With the purpose of identifying new metabolites of BKG, BKG (100 mg/kg) was orally administered to Sprague-Dawley rats via a gavage. Using a metabolic cage, urine was collected for 24 h, and the urine samples were extracted by liquid-liquid extraction. For structural identification of new urinary metabolites of BKG, various instrumental analyses were conducted by gas-chromatography/mass spectrometry, high-performance liquid chromatography/diode array detector, liquid chromatography/mass spectroscopy with thermospray interface and $^1H$ nuclear magnetic resonance spectroscopy. Two metabolites produced from the Ο-demethylation or Ο-dealkylation of BKG were newly identified, and another new but unknown metabolite was assumed to be the hydroxylated form of BKG. These results indicate that the major metabolic products of BKG are formed by Ο-demethylation or Ο-dealkylation of BKG side chains.

• Journal of Ginseng Research
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• 제43권4호
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• pp.539-549
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• 2019

Background: 20(S)-Protopanaxadiol (PPD), the aglycone part of 20(S)-protopanaxadiol ginsenosides, possesses antidepressant activity among many other pharmacological activities. It is currently undergoing clinical trial in China as an antidepressant. Methods: In this study, an ultra-performance liquid chromatography coupled with triple quadrupole time-of-flight mass tandem mass spectrometry method was established to identify the metabolites of PPD in human plasma and urine following oral administration in phase IIa clinical trial. Results: A total of 40 metabolites in human plasma and urine were identified using this method. Four metabolites identified were isolated from rat feces, and two of them were analyzed by NMR to elucidate the exact structures. The structures of isolated compounds were confirmed as (20S,24S)-epoxydammarane-12,23,25-triol-3-one and (20S,24S)-epoxydammarane-3,12,23,25-tetrol. Both compounds were found as metabolites in human for the first time. Upon comparing our findings with the findings of the in vitro study of PPD metabolism in human liver microsomes and human hepatocytes, metabolites with m/z 475.3783 and phase II metabolites were not found in our study whereas metabolites with m/z 505.3530, 523.3641, and 525.3788 were exclusively detected in our experiments. Conclusion: The metabolites identified using ultra-performance liquid chromatography coupled with triple quadrupole time-of-flight mass spectrometry in our study were mostly hydroxylated metabolites. This indicated that PPD was metabolized in human body mainly through phase I hepatic metabolism. The main metabolites are in 20,24-oxide form with multiple hydroxylation sites. Finally, the metabolic pathways of PPD in vivo (human) were proposed based on structural analysis.

• Natural Product Sciences
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• 제16권3호
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• pp.148-152
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• 2010

Microbial metabolism studies of yangonin (1), a major styryl lactone from Piper methysticum, have resulted in the production of three hydroxylated metabolites (2-4). The chemical structures of these compounds were elucidated to be 4-methoxy-6-(12-hydroxystyryl)-2-pyrone (2),4-methoxy-6-(11,12-dihydroxystyryl)-2-pyrone (3),and 4,12-dimethoxy-6-(7,8-dihydroxy-7,8-dihydrostyryl)-2-pyrone (4) on the basis of the chemical and spectroscopic analyses. The compounds 3 and 4 are reported herein as microbial metabolites of yangonin for the first time.