• Archives of Pharmacal Research
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• v.28 no.3
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• pp.249-268
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• 2005

Drug metabolizing enzymes (DMEs) play central roles in the metabolism, elimination and detoxification of xenobiotics and drugs introduced into the human body. Most of the tissues and organs in our body are well equipped with diverse and various DMEs including phase I, phase II metabolizing enzymes and phase III transporters, which are present in abundance either at the basal unstimulated level, and/or are inducible at elevated level after exposure to xenobiotics. Recently, many important advances have been made in the mechanisms that regulate the expression of these drug metabolism genes. Various nuclear receptors including the aryl hydrocarbon receptor (AhR), orphan nuclear receptors, and nuclear factor-erythoroid 2 p45-related factor 2 (Nrf2) have been shown to be the key mediators of drug-induced changes in phase I, phase II metabolizing enzymes as well as phase III transporters involved in efflux mechanisms. For instance, the expression of CYP1 genes can be induced by AhR, which dimerizes with the AhR nuclear translocator (Arnt) , in response to many polycyclic aromatic hydrocarbon (PAHs). Similarly, the steroid family of orphan nuclear receptors, the constitutive androstane receptor (CAR) and pregnane X receptor (PXR), both heterodimerize with the ret-inoid X receptor (RXR), are shown to transcriptionally activate the promoters of CYP2B and CYP3A gene expression by xenobiotics such as phenobarbital-like compounds (CAR) and dexamethasone and rifampin-type of agents (PXR). The peroxisome proliferator activated receptor (PPAR), which is one of the first characterized members of the nuclear hormone receptor, also dimerizes with RXR and has been shown to be activated by lipid lowering agent fib rate-type of compounds leading to transcriptional activation of the promoters on CYP4A gene. CYP7A was recognized as the first target gene of the liver X receptor (LXR), in which the elimination of cholesterol depends on CYP7A. Farnesoid X receptor (FXR) was identified as a bile acid receptor, and its activation results in the inhibition of hepatic acid biosynthesis and increased transport of bile acids from intestinal lumen to the liver, and CYP7A is one of its target genes. The transcriptional activation by these receptors upon binding to the promoters located at the 5-flanking region of these GYP genes generally leads to the induction of their mRNA gene expression. The physiological and the pharmacological implications of common partner of RXR for CAR, PXR, PPAR, LXR and FXR receptors largely remain unknown and are under intense investigations. For the phase II DMEs, phase II gene inducers such as the phenolic compounds butylated hydroxyanisol (BHA), tert-butylhydroquinone (tBHQ), green tea polyphenol (GTP), (-)-epigallocatechin-3-gallate (EGCG) and the isothiocyanates (PEITC, sul­foraphane) generally appear to be electrophiles. They generally possess electrophilic-medi­ated stress response, resulting in the activation of bZIP transcription factors Nrf2 which dimerizes with Mafs and binds to the antioxidant/electrophile response element (ARE/EpRE) promoter, which is located in many phase II DMEs as well as many cellular defensive enzymes such as heme oxygenase-1 (HO-1), with the subsequent induction of the expression of these genes. Phase III transporters, for example, P-glycoprotein (P-gp), multidrug resistance-associated proteins (MRPs), and organic anion transporting polypeptide 2 (OATP2) are expressed in many tissues such as the liver, intestine, kidney, and brain, and play crucial roles in drug absorption, distribution, and excretion. The orphan nuclear receptors PXR and GAR have been shown to be involved in the regulation of these transporters. Along with phase I and phase II enzyme induction, pretreatment with several kinds of inducers has been shown to alter the expression of phase III transporters, and alter the excretion of xenobiotics, which implies that phase III transporters may also be similarly regulated in a coordinated fashion, and provides an important mean to protect the body from xenobiotics insults. It appears that in general, exposure to phase I, phase II and phase III gene inducers may trigger cellular 'stress' response leading to the increase in their gene expression, which ultimately enhance the elimination and clearance of these xenobiotics and/or other 'cellular stresses' including harmful reactive intermediates such as reactive oxygen species (ROS), so that the body will remove the 'stress' expeditiously. Consequently, this homeostatic response of the body plays a central role in the protection of the body against 'environmental' insults such as those elicited by exposure to xenobiotics.

• Korean Journal of Poultry Science
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• v.40 no.3
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• pp.179-185
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• 2013

This study was conducted to investigate the effect of curing additives on color property of smoked duck meat. Curing process of samples was performed one of the following treatments: C, non-curing: T1, 2.43% salt: T2, 2.43% salt + 0.49% tripolyphosphate (TPP): T3, 2.43% salt + 0.49% TPP + 0.002% nitrite: T4, 4.76% duck seasoning: and T5, 1.47% salt + 0.24% TPP + 0.2% L-ascorbic acid. Instrumental meat color of both breast and thigh of smoked duck showed that the CIE $a^*$ value of the T4 was significantly (p<0.05) higher than that of the other treatments, whereas T5 had a significantly (p<0.05) higher CIE $b^*$ value than the other treatments. In results of nitroso pigment, T5 of smoked duck breast was significantly (p<0.05) higher value compared to other treatments, whereas T3 and T5 of smoked duck thigh had a significantly (p<0.05) higher value than other treatments. Heme pigment contents of control and T5 was significantly (p<0.05) higher value compared to other treatments in smoked duck breast. Meat color of T3 by sensory evaluation showed redder (p<0.05) than other treatments. These results suggested that using L-ascorbic acid is revealed to be pink color without nitrite or pigment when manufacturing of smoked duck meat.

• Food Science of Animal Resources
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• v.23 no.3
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• pp.236-249
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• 2003

To investigate the effects of dietary conjugated linoleic acid 011 changes of physicochemical properties of pork. Twenty pigs were divided into 5 treatment groups and subjected to each experimental diet(0, 1.25% and 2.5% CLA for 2 weeks, 1.25% and 2.5% CLA for 4 weeks, as total fed diet before slaughtering(about 110 kg). Pork loin samples were aerobically packed and stored for 14 days at 4$^{\circ}C$. Samples were then analyzed for general compositions, physicochemical characteristics and sensory evaluation. pH value of CLA fed group pork was significantly increased than that of control group(p<0.05). Crude fat content of CLA treated group pork was significantly higher than the control pork(p<0.05), but there were no significant differences in crude protein, crude ash and total moisture contents between control and CLA treated groups. AU CLA fed group pork showed higher WHC value than control pork. Drip loss was significantly lower compared to those of control porks. No significant differences in lean meat and fat color(CIE L*, a*, b*) were observed between control and the CLA treated group porks. Meanwhile, CLA pork tended to be lower in content of total heme pigment compared to control pork. No remarkable differences were found in sensory properties(color and drip loss) among control and CLA diet-fed group porks. Marbling score and acceptability were significantly increased in CLA diet-fed pork compared to the control pork.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.10
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• pp.1446-1451
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• 2010

Silk sericin protein was hydrolyzed by seven proteolytic enzymes to examine the effectiveness of the hydrolysates to bind iron. The amino acid nitrogen contents of hydrolysates by Flavourzyme were higher than the others enzymes, and its iron binding capacity showed dose-dependent increase. The bioavailability of iron binding peptide from sericin hydolysates was investigated in iron-deficient rats. Three-week-old male rats were fed iron-deficient diet for three weeks. Rats were divided into four groups (DD: no treated group on iron deficient diet, DD+HI: heme-iron treated group, DD+OI: sericin-Fe, and DD+II: inorganic iron ($FeSO_4$) treated group, and then iron supplemented by injection for one week. After oral administration for one week, the iron contents of serum and liver were significantly higher in DD+OI ($4.2\;{\mu}g/mL$ and $80.1\;{\mu}g/mL$) and DD+HI ($3.2\;{\mu}g/mL$ and $70.6\;{\mu}g/mL$) than DD ($2.0\;{\mu}g/mL$ and $47.9\;{\mu}g/mL$). Hemoglobin content of treated groups was significantly higher than DD, but the significant difference among groups was not shown. Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels did not show any significant difference among all groups. Binding iron to peptide from sericin hydolysates seems to improve its bioavailability and to hasten the cure of iron deficiency in experimental rat.

• Microbiology and Biotechnology Letters
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• v.42 no.2
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• pp.170-176
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• 2014

In this study, the anti-oxidative and anti-inflammatory activities of Euptelea pleiosperma ethanol extract (EPEE) were evaluated using in vitro assays and cell culture model systems. EPEE possessed a more potent scavenging activity against 1,1-diphenyl-2-picryl hydrazyl than the ascorbic acid used as a positive control. EPEE effectively suppressed lipopolysaccharide (LPS), in addition to hydrogen peroxide induced reactive oxygen species on RAW 264.7 cells. Furthermore, EPEE induced the expression of the anti-oxidative enzyme heme oxygenase 1 (HO-1) and its upstream transcription factor, nuclear factor-E2-related factor 2 (Nrf2), dose and time dependently. The modulation of HO-1 and Nrf2 expression might be regulated by mitogen-activated protein kinases and phosphatidyl inositol 3 kinase/Akt as their upstream signaling pathways. On the other hand, EPEE inhibited LPS induced nitric oxide (NO) formation without cytotoxicity. Suppression of NO formation was the result of the down regulation of inducible NO synthase (iNOS) by EPEE. Suppression of NO and iNOS by EPEE may be modulated by their upstream transcription factor, nuclear factor ${\kappa}B$, and AP-1 pathways. Taken together, these results provide important new insights into E. pleiosperma, namely that it possesses anti-oxidative and anti-inflammatory activities, indicating that it could be utilized as a promising material in the field of nutraceuticals.

• Journal of Life Science
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• v.29 no.11
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• pp.1273-1280
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• 2019

Age-related macular degeneration (AMD) is one of the leading causes of blindness in the elderly population, and damage to retinal pigment epithelial (RPE) cells due to oxidative stress contributes to the development of AMD. Glycyrrhiza uralensis Fischer is one of the most widely used herbal medicines for the treatment of various diseases in Asian countries. Although recent studies indicated that treatment with G. uralensis can protect cells from oxidative stress, its mechanisms in RPE cells remain unknown. We evaluated the effect of a G. uralensis ethanol extract (GU) on $H_2O_2$-induced oxidative injury in ARPE-19 RPE cells. The GU pretreatment attenuated reactive oxygen species (ROS) generation induced by $H_2O_2$, which was associated with induced expression of nuclear factor erythroid-derived-2-like 2 (Nrf2) and heme oxygenase-1 (HO-1). GU also suppressed $H_2O_2$-induced DNA damage and mitochondrial dysfunction. The inhibitory effect of GU on $H_2O_2$-induced apoptosis was associated with the protection of caspase-3 activation. Overall, GU appeared to protect RPE cells from oxidative injury by inhibiting DNA damage and reducing apoptosis. Further studies are needed to determine the regulation of Nrf2-mediated HO-1 expression, but our results suggest the possibility of using GU to reduce the risk of AMD.

• Korean Chemical Engineering Research
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• v.60 no.4
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• pp.588-593
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• 2022

Terephthalaldehyde (TPA) is introduced as a cross liker to enhance electron transfer of hemin-based cathodic catalyst consisting of polyethyleneimine (PEI), carbon nanotube (CNT) for hydrogen peroxide reduction reaction (HPRR). In the cyclic voltammetry (CV) test with 10 mM H₂O₂ in phosphate buffer solution (pH 7.4), the current density for HPRR of the suggested catalyst (CNT/PEI/hemin/PEI/TPA) shows 0.2813 mA cm^-2 (at 0.2 V vs. Ag/AgCl), which is 2.43 and 1.87 times of non-cross-linked (CNT/PEI/hemin/PEI) and conventional cross liker (glutaraldehyde, GA) used catalyst (CNT/PEI/hemin/PEI/GA), respectively. In the case of onset potential for HPRR, that of CNT/PEI/hemin/PEI/TPA is observed at 0.544 V, while those of CNT/PEI/hemin/PEI and CNT/PEI/hemin/PEI/GA are 0.511 and 0.471 V, respectively. These results indicate that TPA plays a role in facilitating electron transfer between the electrodes and substrates due to the π-conjugated cross-linking bonds, whereas conventional GA cross-linker increases the overpotential by interrupting electron and mass transfer. Electrochemical impedance spectroscopy (EIS) results also display the same tendency. The charge transfer resistance (R_ct) of CNT/PEI/hemin/PEI/TPA decreases about 6.2% from that of CNT/PEI/hemin/PEI, while CNT/PEI/hemin/PEI/GA shows the highest R_ct. The polarization curve using each catalyst also supports the superiority of TPA cross liker. The maximum power density of CNT/PEI/hemin/PEI/TPA (36.34±1.41 μWcm^-2) is significantly higher than those of CNT/PEI/hemin/PEI (27.87±0.95 μWcm^-2) and CNT/PEI/hemin/PEI/GA (25.57±1.32 μWcm^-2), demonstrating again that the cathode using TPA has the best performance in HPRR.