• Bulletin of the Korean Chemical Society
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• v.28 no.7
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• pp.1151-1155
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• 2007

In a previous study, a catalyst (A) was discovered for oxidative decarboxylation of melanin-concentrating hormone (MCH). To explain the catalytic action and to predict the structure of a new catalyst with improved activity, docking simulations were carried out for the complex formed between A and MCH. The simulations suggested that the three terminal groups of A form a hydrophobic pocket and that van der Waals interactions between the hydrophobic pocket and MCH play a role in stabilizing the MCH-A complex. Consequently, a new catalyst (B) was designed and synthesized in expectation of improved catalytic activity resulting from enhanced van der Waals interactions. The new catalyst, however, showed slightly lower catalytic activity. Lack of the accurate solution structure of MCH may be one of the factors associated with difficulties in prediction of improvement in catalytic activity by purely theoretical means. The results, however, revealed that variation of the acyl portion of the hydroxyproline portion may lead to improved catalysts.

• BMB Reports
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• v.32 no.1
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• pp.67-71
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• 1999

We have investigated the effect of cholestasis on the closely related acyl-CoA:amino acid N-acyltransferase, benzoyltransferase, and phenylacetyltransferase activities in rat liver. Benzoyltransferase and phenylacetyltransferase activities in the liver cytosol, mitochondria, and microsome were investigated for a period of 42 d after common bile duct ligation. Both the mitochondrial and microsomal benzoyltransferases showed significant increase in their activities between the 1st and 7th day after common bile duct ligation, although the cytosolic benzoyltransferase activity did not show a significant change compared to the activities from the sham-operated control. The cytosolic phenylacetyltransferase activity showed a significant increase between the 1st and 2nd day, the mitochondrial activity showed a significant increase between the 2nd and 7th day, and microsomal activity showed a significant increase between the 1st and 7th day, respectively. Enzyme kinetic parameters of hepatic benzoyltransferase were analyzed using benzoyl coenzyme A as a substrate with the preparations from the 1st day post-ligation. Enzyme parameters of hepatic phenylacetyltransferase were also analyzed using phenylacetyl coenzyme A as a substrate with the preparations from the 2nd day post-ligation. The results indicated that although the $K_m$ values of these enzymes were about the same as the sham-operated control, the $V_{max}$ values of both enzymes increased significantly. These results, therefore, suggest that the biosynthesis of benzoyltransferase and phenylacetyltransferase has been induced in response to cholestasis.

• Toxicological Research
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• v.26 no.1
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• pp.15-19
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• 2010

Mesenchymal stem cells (MSCs) have greater potential for immediate clinical and toxicological applications, due to their ability to self-renew, proliferate, and differentiate into a variety of cell types. To identify novel candidate genes that were specifically expressed during transdifferentiation of human MSCs to neuronal cells, we performed a differential expression analysis with random priming approach using annealing control primer-based differential display reverse transcription-polymerase chain reaction approach. We identified genes for acyl-CoA thioesterase, tissue inhibitor of metalloproteinases-1, brain glycogen phosphorylase, ubiquitin C-terminal hydrolase and aldehyde reductase were up-regualted, whereas genes for transgelin and heparan sulfate proteoglycan were down-regulated in MSC-derived neurons. These differentially expressed genes may have potential role in regulation of neurogenesis. This study could be applied to environmental toxicology in the field of testing the toxicity of a chemical or a physical agent.

• Archives of Pharmacal Research
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• v.28 no.5
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• pp.550-556
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• 2005

The flower of Campsis grandiflora K. Schum. Was extracted with 80% aqueous MeOH, and the concentrated extract was partitioned with EtOAc, n-BuOH and H$_2$O. From the EtO Ac fraction, seven triterpenoids were isolated through the repeated silica gel, ODS column chromatographies and preparative HPLC. From the result of physico- chemical data including NMR, MS and IR, the chemical structures of the compounds were determined as 3${\beta}$-hydroxyolean-12-en-28-oic acid (oleanolic acid, 1), 3${\beta}$-hydroxyurs-12-en-28-oic acid (ursolic acid, 2), 3${\beta}$-hydroxyurs-12-en-28-al (ursolic aldehyde, 3), 2${\alpha}$,3${\beta}$-dihydroxyolean-12-en-28-oic acid (maslinic acid, 4), 2${\alpha}$,3${\beta}$-dihydroxyurs-12-en-28-oic acid (corosolic acid, 5), 3${\beta}$,23-dihydroxyurs-12- en-28-oic acid (23-hydroxyursolic acid ,6) and 2${\alpha}$,3${\beta}$,23-trihydroxyolean-12-en-28- oic acid (arjunolic acid, 7). These teriterpenoids were isolated for the first time from this plant. Also, compounds 4, 5, 6, and 7 revealed relatively high hACAT-1 inhibitory activity with the value of 46.2${\pm}$1.1, 46.7${\pm}$0.9, 41.5${\pm}$1.3 and 60.8${\pm}$1.1% at the concentration of 100${\mu}$g/mL, respectively.

• Biomedical Science Letters
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• v.12 no.2
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• pp.65-72
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• 2006

Thiazolidinediones (TZDs) are widely used antidiabetic drugs that activate the nuclear peroxisome proliferator-activated receptor ${\gamma}(PPAR{\gamma})$, and thereby improve the metabolic abnormalities linking hypertriglyceridemia to diabetes, hyperglycemia, insulin resistance, and cardiovascular disease. To determine whether the $PPAR{\gamma}$ ligand troglitazone regulates lipid metabolism with sexual dimorphism, we examined the effects of troglitazone on circulating lipids, body weight and the expression of hepatic genes responsible for lipid metabolism in both sexes of C57BL/6J mice. Compared to mice fed a low fat control diet, both sexes of mice fed a troglitazone-treated low fat diet for 14 weeks did not exhibit changes in body weight gain, serum total cholesterol, HDL-cholesterol and LDL-cholesterol levels. However, serum triglycerides were significantly reduced in both sexes of mice, although these effects were more pronounced among males. Furthermore, troglitazone regulated the expression of hepatic genes critical for lipid and lipoprotein metabolism, the magnitudes of which were much higher in males compared to females, as evidenced by results for increased acyl-CoA oxidase and decreased apolipoprotein C-III mRMA levels. These results suggest that $PPAR{\gamma}$ activator troglitazone may exert sexually dimorphic control of serum triglycerides in part through the differential activation of $PPAR{\gamma}$ in liver between male and female mice.

• Journal of Life Science
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• v.9 no.4
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• pp.382-388
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• 1999

The effects of citrus flavonoids, hesperidin and naringin, on the lipid metabolism were investigated in cultured human hepatocyte HePG2 cells. HepG2 cells were cultured for 6 h and 24 h to the control medium or the media containing hespridin and narigin, which concentrations were 0.5 and 5.0 mg/$m\ell$. There were no significant effects on cell proliferation and cellular protein content, except for increased in these parameters by adding both citrus flavonoids (0.5 mg/$m\ell$). The cellular content of triacylglycerol after 6 h incubation with 0.5 mg/$m\ell$ hesperidin and naringin was markedly increased, and after 24 h incubation that was decreased in both citrus flavonoids supplementation. The supplementation of 5.0 mg/$m\ell$ hesperidin caused a marked decrease in the cellular cholesterol content following 6 h incubation, and that was also reduced markdly, in a dose-dependent manner, during incubation for 24 h. However, there was no significant difference in the cellular cholesterol content in medium supplemented with naringin. The effect of hesperidin and naringin on acyl-CoA: cholesterol acyltransferase (ACAT) activity was studied in vivo and in vitro. The data confirmed that hesperidin inhibit ACAT activity in vivo and in vitro, whereas naringin had no such effect on ACAT activity in vivo but not in vitro. The present study suggests that hesperidin reduces the cellular triacyglycerol and cholesterol contents in human hepatocyte HepG2 cells.

• Nutrition Research and Practice
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• v.7 no.3
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• pp.153-159
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• 2013

We investigated whether the combination of phytochemicals and acetic acid in the form of fruit vinegar provides an additive effect on changes of mRNA levels related to fatty acid oxidation in human hepatocyte (HepG2). Among the seven fruit vinegars (Rubuscoreanus, Opuntia, blueberry, cherry, red ginseng, mulberry, and pomegranate) studied, treatment of HepG2 with pomegranate vinegar (PV) at concentrations containing 1 mM acetic acid showed the highest in vitro potentiating effect on the mRNA expression levels of peroxisome proliferator-activated receptor ${\alpha}$, carnitinepalmitoyl transferase-1, and acyl-CoA oxidase compared to the control group (P < 0.05). Reversed-phase liquid chromatography in combination with quadrupole time-of-flight mass spectrometry analysis revealed four potential compounds (punicalagin B, ellagic acid, and two unidentified compounds) responsible for altered gene expression in HepG2 cells treated with PV as compared with the others. Further investigations are warranted to determine if drinking PV beverages may help to maintain a healthy body weight in overweight subjects.

• The Korean Journal of Physiology and Pharmacology
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• v.9 no.3
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• pp.173-177
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• 2005

The purpose of this study was to discern the critical point in skeletal muscle fatty acid oxidation by changing plasma free fatty acids (FFA) level in rat. In the study, 3 key steps in lipid oxidation were examined after changing plasma FFA level by acipimox. The rates of both palmitate and palmitoylcarnitine oxidation were decreased by decrease of plasma FFA level, however, carnitine palmitoyl transferase (CPT) 1 activity was not changed, suggesting CPT1 activity may not be involved in the fatty acid oxidation at the early phase of plasma FFA change. In the fasted rats, ${\beta}-hydroxy$ acyl-CoA dehydrogenase (${\beta}$-HAD) activity was depressed to a similar extent as palmitate oxidation by a decrease of plasma FFA level. This suggested that ${\beta}-oxidation$ might be an important process to regulate fatty acid oxidation at the early period of plasma FFA change. Citrate synthase activity was not altered by the change of plasma FFA level. In conclusion, the critical step in fatty acids oxidation of skeletal muscles by the change of plasma FFA level by acipimox in fasting rats might be the ${\beta}-oxidation$ step rather than CPT1 and TCA cycle pathways.

• Korean Journal of Pharmacognosy
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• v.35 no.3 s.138
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• pp.233-238
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• 2004

Lipoprotein-associated phospholipase $A_2\;(Lp-PLA_2)$ is a potential biomarker of coronary heart disease and plays an important proinflammatory role in the progression of atherosclerosis. Also acyl-CoA: cholesterol acyltransferase (ACAT) and oxidized low-density lipoprotein (LDL) playa key role in atherosclerosis, respectively. And so, the inhibitory activities of the methanol extracts of 42 insect resources were examined on $Lp-PLA_2$, ACAT, and LDL oxidation for screening of anti-atherogenic substances. Among them, the methanol extracts of Eurydema rugosa significantly inhibited all of upper three activities. Several kinds of tested insects having high inhibitory effect with the methanol extracts were extracted with n-hexane, ethyl acetate, and acetone, and their inhibitory activities were tested.

• Journal of Applied Biological Chemistry
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• v.43 no.4
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• pp.230-234
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• 2000

A new method to assay the capsaicinoid synthetase (CS) activity was developed by utilizing NADHcoupled enzyme systems involving pyruvate kinase and lactate dehydrogenase. CS activities in Capsicum placenta, depending upon the kinetics of the NADH oxidation, revealed almost the same profile as compared with those shown using an HPLC-based method. When the substrates, 8-methyl nonanoic acid and vanillylamine, for the CS enzyme were employed separately or simultaneously, it appeared that the two-step reaction, acyl-CoA formation and condensation with vanillyla~ne, of the CS enzyme was a coupled reaction. Thus, this assay method of the CS enzyme can be considered as an alternative to the HPLC-based method, since it has the advantages of rapidity and simplicity as well as reliability when compared with the existing method.