• Mass Spectrometry Letters
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• 제6권2호
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• pp.48-51
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• 2015

Kinsenoside is a principle bioactive compound of Anoectochilus formosanus. It exhibits various pharmacological effects such as antihyperglycemic, antioxidant, anti-inflammatory, immunostimulating, and hepatoprotective activities and has recently been developed as an antidiabetic drug candidate. In this study, as part of an in vitro pharmacokinetic study, the stability of kinsenoside in rat and human liver microsomes was evaluated. Kinsenoside was found to have good metabolic stability in both rat and human liver microsomes. These results will provide useful information for further in vivo pharmacokinetic and metabolism studies.

• 한국환경성돌연변이발암원학회지
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• 제9권2호
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• pp.87-96
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• 1989

Studies on the biodisposition of beta-nicotyrine by lung and liver microsomes was examined in order to provide a better understanding of its fate in this tissue. beta-nicotyrine (100$\mu$M) was incubated with microsomes (1 mg/ml) prepared from New Zealand White rabbits. The rate of oxidation observed in lung microsomal incubations was 1.7 nmoles $\beta$-nicotyrine oxidized mg$^{-1}$ min$^{-1}$ compared with 2.7 nmoles $\beta$-nicotyrine oxidized mg$^{-1}$ min$^{-1}$ by the liver microsomal preparation. However, when these rates were expressed as a function of cytochrome P-450 content, the specific activity of the metabolic oxidation catalyzed by lung (8.3 nmoles $\beta$-nicotyrine oxidized nmole cytochrome P-450$^{-1}$ min$^{-1}$) was approxiamtely 4 times greater than liver microsomes (2.3 nmoles $\beta$-nicotyrine oxidized nmole cytochrome P-450$^{-1}$ min$^{-1}$). Isozyme studies on the oxidation of $\beta$-nicotyrine employed several methods of altering activities of specific isozymes present in pulmonary microsomes, including the use of the isozyme 2 and 6 specific inhibitor $\alpa$-methyl ABT, metabolic inhibitor(MI) complex formation. The results of this inhibition study would appear to indicate the $\beta$-nicotyrine is metabolized predominantly by pulmonary isozyme 5.

• 대한예방한의학회지
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• 제7권2호
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• pp.65-74
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• 2003

Objective : The aim of present study is to evaluate the inhibitory potential of licorice extract and glycyrrhizin on cytochrome P450(CYP) in human liver microsomes. Methods : Using human liver microsomes, water extract of licorice and glycyrrhizin as an inhibitor were co-incubated with each probe drug representing selective CYP isoform activity. We measured relative metabolic activity in incubation condition compared to that with no extract of licorice using HPLC system. Results : Both water extracts of licorice and glycyrrhizin showed inhibitory effect on CYP-catalyzed reactions. CYP2C19 $(IC_{50}=126.7{\mu}g/ml)$ is most potently inhibited by water extract than other tested CYP isoforms$(IC_{50}>450{\mu}g/ml)$, but glycyrrhizin exhibited potent inhibition on CYP1A2$(IC_{50}=106.9{\mu}g/ml)$ followed by CYP2C9 and CYP2D6. Conclusion: These results indicate that water extract of licorice and glycyrrhizin have inhibitory potential on CYP-catalyzed reaction in human liver microsomes. But the mechanism of inhibition was slightly different between them Water extract of licorice mainly inhibited CYP2C19, and glycyrrhizin primarily inhibited CYP1A2. The inhibition by water extract of licorice and glycyrrhizin on CYP isoforms may cause drug interaction with co-administered drug leading to toxicity or treatment failure.

• Archives of Pharmacal Research
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• 제11권4호
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• pp.292-300
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• 1988

Metabolism of tranylcypromine (TCP) in rat liver microsomes was studied in vitro using fortified microsomal preparations. As well as unlabeled TCP, two deuterium labeled analogs, TCP-phenyl-$d_{5}$ and TCP-cyclopropyl-$d_{2}$ were used and GC/MS employed which was then metabolized to cinnamaldehyde and hydrocinnamyl alcohol. Schiff bases of TCP with hydrocinnamaldehyde and acetaldehyde were detected and possibility of the metabolic formation of N-ethylidene TCP was proposed. In addition, acetophenone (benzoylacetic acid), benzaldehyde, benzoic acid, and benzyl alcohol were detected as the metabolites. Chemical decomposition studies suggested that parts of the oxidized products might be derived by air oxidation processes. A potential metabolite assumed to be N-ethylidene-1, 2-dihydroxy-3-phenylpropanamine oxide was also detected.

• 대한약학회:학술대회논문집
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• 대한약학회 2003년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.1
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• pp.286.2-287
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• 2003

The purpose of this paper was to identify the metabolic pathway of a new neuroprotective agent, KR-31543 for ischemia-reperfusion damage in human liver microsomes and characterize cytochrome P450 (CYP) enzymes involved in the in vitro metabolism of KR-31543 generates two metabolites in human liver microsomes : M1, N-(4-chlorophenyl)-N-(2-methyl-2H-tetrazol-5-ylmethyl)amine and M2, hydroxy-KR-31543. (omitted)

• Toxicological Research
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• 제18권4호
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• pp.331-339
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• 2002

Phenoxy compounds, 2,4-Dichlorophenol acetoxy acid (2,4-D) and 2,4-dichlorophenol (DCP), are widely used as a hormonal herbicide and intermediate for pesticide manufacturing, respectively. In order to assess the potential of these compounds as endocrine disruptors, we studied the androgenicity of them wing in vivo and in vitro androgenicity assay system. Administration of 2,4-D (50 mg/kg/day, p.o.) or DCP (100 mg/kg/day, p.o.) to rats caused an increase in the tissue weight of ventral prostate, Cowpers gland and glands penis. These increase of androgen-dependent tissues were additively potentiated when rats were simultaneously treated with low dose of testosterone (1 g/kg, s.c.). 2,4-D increased about 350% of the luciferase activity in the PC cells transiently cotransfected phAR and pMMTV-Luc at concentration of $10^{-9}$ M. In 2,4-D or DCP-treated castrated rats, testosterone 6$\beta$-hydroxylase activity was not significantly modulated even when rats were co-treated with testosterone. In vitro incubation of 2,4-D and DCP with microsomes at 50 $\mu$M inhibited testosterone 6$\beta$-hydroxylase activity about 27% and 66% in rat liver microsomes, about 44% and 54% in human liver microsomes and about 50% and 45% in recombinant CYP3A4 system, respectively. The amounts of total testosterone metabolites were reduced about 33% and 75% in rat liver microsomes, 69% and 73% in human liver microsomes and 54% and 64% in recombinant CYP3A4 by 2,4-D or DCP, respectively. Therefore, the additive androgenic effect of 2,4-D or DCP by the co-administration of the low dose of testosterone may be due to the increased plasma level of testosterone by inhibiting the cytochrome P450-mediated metabolism of testosterone. These results collectively suggested that 2,4-D and DCP may act as androgenic endocrine disrupter by binding to the androgen receptor as well as by inhibiting the metabolism of testosterone.

• Biomolecules & Therapeutics
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• 제2권3호
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• pp.236-243
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• 1994

A splenocyte culture system supplemented with liver microsomes was developed to detect immunotoxic chemicals which require metabolic activation using cyclophosphamide as a positive standard. When liver microsomes were added to splenocyte cultures isolated from female B6C3Fl mice, the proliferation of splenocytes by lipopolysaccharide (LPS) was increased and the proliferation by concanavalin A (Con A) was decreased. However, when compared with each corresponding control, cyclophophamide was successfully activated to metabolites capable of suppressing Iymphoproliferative responses. This suppression was clearly dependent upon the amounts of microsomes added and/or the concentration of cyclophosphamide exposed. In these cultures, the proliferation of splenocytes was suppressed when the cells were exposed to cyclophosphamide on the day of culture initiation. On the other hand, microsome was responsible for the increase in LPS mitogenicity and NADPH was responsible for the decrease in Con A mitogenicity. Finally, our present culture system was compared with the hepatocyte-splenocyte coculture system which we had developed earlier. We found that the hepatocyte-splenocyte coculture was better able to activate cyclophosphamide to metabolites capable of suppressing the antibody response to sheep erythrocytes. Although our present culture system was relatively poor to activate cyclophosphamide in cultures for antibody response, it will be useful as a simple screening method to detect suppression of certain in vitro immunotoxic parameters like LPS mitogenicity by chemicals which require metabolism.

• 한국연초학회지
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• 제20권2호
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• pp.178-182
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• 1998

Previously, we showed that acetone enhanced aryl hydrocarbon hydroxylase (AHH) activity in only 3-methylcholanthrene (MC)- or $\beta$-naphtoflavone (BNF)-inducible microsomes of rat liver. In the present study, the possible mechanism underlying acetone action on AHH was investigated in the liver microsomes from MC-pretreated rats. Other n-alkylketones except acetone did not increase AHH activity, which rather decreased significantly with the length of alkyl side chain. Acetone had no effect on the activity of NADPH-cytochrome P450 reductase or inhibited the formation of 3-OH benzo(a)pyrene (B(a)P) in nonenzymatic model ascorbic acid system. However, in cumene hydroperoxide (CuOOH)-supported B(a)P hydroxylation, acetone enhanced its velocity remarkably by 30% at the optimal concentration (30 $\mu$M CuOOH and 1.0% acetone). From these results, we conclude that acetone may facilitate the formation of an activated oxygen species or the insertion of oxygen into B(a)P molecule in CYP1A rich microsomes.

• 한국식생활문화학회지
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• 제4권2호
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• pp.185-189
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• 1989

Effect of perilla oil on the fatty acid composition, ACAT and HMG-CoA reductase in the liver microsomes, or cholesterol and protein in serum of rabbit were examined. 1. The content of total protein in serum was almost same amount of both groups, but ${\alpha_1}-globulin$ and r-globuline were incresed or ${\beta}-globulin$ was decresed compared with control. 2. The content of high density lipoprotein incresed, and the content of low density lipoprotein decresed in lipoprotein. 3. Total cholesterol and triglyceride were decresed, and the content of phospholipid was incresed. 4. Perilla oil did not effect for changing blood glucose and $Na^+,\;K^+$ electrolytes. 5. Perilla oil did not effect for changing serum GOT and GPT in rabbit. 6. The activity of ACAT decresed and the activity of HMG-CoA reductase incresed. The activity of ACAT and HMG-CoA reductase in liver microsomes were reciprocal. 7. There were arachidonic acid 20:4, eicosapentaenoic acid 20:5, and docosahexaenoic acid 22:6 in the liver microsomes of rabbits. These highly polyunsaturated fatty acids were convented from linolenic acid 18:3 n-3.

• Archives of Pharmacal Research
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• 제21권6호
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• pp.677-682
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• 1998

The present study was designed to examine the metabolism of 1-anilino-8-naphthalene sulfonate (ANS), an anionic compound which is transported into liver via "multispecific organ ic anion transporter", with rat hepatic microsomes. TLC analysis indicated that the fluorescent metabolites were not produced to a measurable extent, which made it possible to assess the ANS metabolism by measuring the fluorescence disappearance. The metabolism of ANS was remarkably inhibited by the presence of SKF-525A as well as by the substitution of 02 by CO gas. ANS metabolism by microsomes also required NADPH as a cofactor. These results indicated that the microsomal monooxygenase system might be mainly responsible for the ANS metabolism. The maximum velocity ($V_{max}$) and Michaelis constant ($K_m$) were calculated to be $4.3{\pm}0.2$ nmol/min/mg protein and $42.1{\pm}2.0\;{\mu}M$, respectively. Assuming that 1g of liver contains 32mg of microsomal protein, the $V_{max}$ value was extrapolated to that per g of liver ($V_{max}^I$). The intrinsic metabolic clearance ($CL_{int}$) under linear conditions calculated from this in vitro metabolic study was 3.3ml/min/g liver, being comparable with that (3.0ml/min/g liver) calculated by analyzing the in vivo plasma disappearance curve in a previous study. Furthermore, the effects of other organic anions on the metabolism of ANS were examined. Bromophenolblue (BPB) and rose bengal (RB) competitively inhibited the metabolism of ANS, while BSP inhibited it only slightly. The inhibition constant ($K_i$) of BPB ($6\;{\mu}M$) was much smaller than that of RB ($200\;{\mu}M$). In conclusion, the microsomal monooxygenase system plays a major role in the metabolism of ANS, and other unmetabolizable organic anions (BPB and RB) compete for this metabolism.