• Journal of Applied Biological Chemistry
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• v.44 no.4
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• pp.159-162
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• 2001

Plant stress incurred by flooding was studied in terms of oxidative stress, using greened rice seedlings subjected to a complete submergence followed by re-exposure to air under illumination ($30W/m^2$). It appeared that shoot tissues of the seedlings suffered oxygen deficiency during the flooding treatment, pertinent to the general concept. Interestingly enough, however, membrane peroxidation in shoots was enhanced by the submergence, as assessed by the content of 2-thiobarbituric acid-reactive substances (TBARS), and the re-aeration resulted in a rapid reduction of TBARS content. Such pattern of response was also seen in the change in the steady state level of $H_2O_2$. In contrast, superoxide dismutase and glutathione reductase that are involved in the detoxifying processes of superoxide in plant cells were significantly activated only during the re-aeration. These results allowed us to suggest the followings as a working hypothesis. Photorespiration-linked production of $H_2O_2$ may largely contribute to the increase in $H_2O_2$ level as well as TBARS production in shoots during the submergence. An abrupt re-supply of $CO_2$ by the re-aeration brings the photosynthetic apparatus back to full operation, suppressing photorespiration and probably causing a momentary, excess formation of superoxide and its dismutation product through side reaction, which gives rise to activating substrate-inducible antioxidative enzymes.

• Journal of Physiology & Pathology in Korean Medicine
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• v.22 no.6
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• pp.1525-1531
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• 2008

Acer tegmentosum Max which is one of the specialized wildness medicinal herbs in gangwon province, has been widely used for hepatitis, liver cirrhosis, hepatic cancer, leukemia, diabetes mellitus, renal necrosis and edema, etc. In this study, the antioxidative and hepatoprotective effects of in vitro and in vivo were investigated in order to evaluate the possibility as hepatoprotective agents. Oral administration of methanol and butanol extact of Acer tegmentosum Max to d-galactosamine (D-GaIN) induced experimental liver injured rats was significantly reduced activities of marker enzymes(AST, ALT) and LDH activity in serum. Salidroside(Sal) isolated from the BuOH extract of Acer termentosum Max potenty showed the scavenzing effect on DPPH and inhibitory effect on lipid peroxidation. And significantly decrcease of MDA level in liver and activities of SOD GSH-Px and catalase were significantly improved by the treatment of Sal. Results of this study revealed that Sal could afford a significant protection in the alleviation of D-GaIN-induced hepatocellular injury.

• Biomedical Science Letters
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• v.14 no.1
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• pp.19-26
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• 2008

This study investigated the effect of Rehmanniae Radix preparata extract on the antioxidant enzymes of kidney and renal function in streptozotocin-induced diabetic rats. Male Sprague-Dawley rats were divided into three groups including normal control (NC), diabetic control (DC), and diabetic treatment with Rehmanniae Radix preparata (DRR). Over a 4-week study period, Rehmanniae Radix preparata aqueous extract was administered orally at 1124 mg/kg BW/day. The serum glucose level in the DRR group was significantly lower (P<0.05) than the DC group. The serum blood urea nitrogen in diabetic groups was significantly higher (P<0.001) than the NC group. The urinary total protein level in the DRR group was significantly lower (P<0.05) than the DC group. The renal xanthine oxidase activity in the DRR group was significantly lower (P<0.01) than the DC group. The renal catalase activity in the DC group was significantly lower (P<0.05) compared to the NC group and that was significantly higher (P<0.05) in the DRR group than the DC group. In conclusion, these results indicated that Rehmanniae Radix preparata can prevent or retard the development of diabetic nephropathy via its beneficial effects for correcting the hyperglycemia and favorable effects on antioxidant enzyme system.

• Preventive Nutrition and Food Science
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• v.14 no.1
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• pp.37-42
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• 2009

The protective activity of seolitae chungkukjang added with green tea against oxidative stress was investigated under the cellular systems using LLC-$PK_1$ cells. The treatment of 2,2'-azobis(2-aminopropane) dihydrochloride (AAPH) showed increase in lipid peroxidation, and decrease in endogenous antioxidant enzymes activity and cell viability. However, the methanol extract of seolitae chungkukjang inhibited lipid peroxidation by 58.3%, and increased cell viability up to more than 60%. In addition, it enhanced superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities. Seolitae chungkukjang improved oxidative stress-induced cellular injury through the radical scavenging activities. In particular, the addition of green tea in seolitae chungkukjang showed stronger effect against oxidative stress induced by AAPH. The more addition of green tea resulted in the greater antioxidative effect through elevation in activities of SOD and GSH-Px, and inhibition of lipid peroxidation, eventually leading to increase in cell viability. Theses results suggested that seolitae chungkukjang added with green tea have protective effects from cellular oxidative damage and could be considered as an application for the development of chungkukjang with functionality.

• Preventive Nutrition and Food Science
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• v.15 no.1
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• pp.7-13
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• 2010

We investigated whether the fermented soymilk extract (FSE) has protective effects against high glucose-induced oxidative stress in human umbilical vein endothelial cells (HUVECs). FSE was prepared via fermentation of soymilk with Bacillus subtilis followed by methanol extraction. To determine the protective effect of FSE, oxidative stress was induced by exposing of HUVECs to the high glucose (30 mM) for 48 hr. Exposure of HUVECs to high glucose for 48 hr resulted in a significant (p<0.05) decrease in cell viability, catalase, SOD and GSH-px activity and a significant (p<0.05) increase in intracellular ROS level and thiobarbituric acid reactive substances (TBARS) formation in comparison to the cells treated with 5.5 mM glucose. However, at concentration of 0.1 mg/mL, FSE treatment decreased intracellular ROS level and TBARS formation, and increased cell viability and activities of antioxidant enzymes including catalase, SOD and GSH-px in high glucose pretreated HUVEC. These results suggest that FSE may be able to protect HUVECs from high glucose-induced oxidative stress, partially through the antioxidative defense systems.

• Journal of Microbiology and Biotechnology
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• v.28 no.3
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• pp.418-424
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• 2018

${\text\tiny{D}}-Allose$ is a potential medical sugar because it has anticancer, antihypertensive, antiinflammatory, antioxidative, and immunosuppressant activities. Allose production from fructose as a cheap substrate was performed by a one-pot reaction using Flavonifractor plautii ${\text\tiny{D}}-allulose$ 3-epimerase (FP-DAE) and Clostridium thermocellum ribose 5-phosphate isomerase (CT-RPI). The optimal reaction conditions for allose production were pH 7.5, $60^{\circ}C$, 0.1 g/l FP-DAE, 12 g/l CT-RPI, and 600 g/l fructose in the presence of 1 mM $Co^{2+}$. Under these optimized conditions, FP-DAE and CT-RPI produced 79 g/l allose for 2 h, with a conversion yield of 13%. This is the first biotransformation of fructose to allose by a two-enzyme system. The production of allose by a one-pot reaction using FP-DAE and CT-RPI was 1.3-fold higher than that by a two-step reaction using the two enzymes.

• Nutrition Research and Practice
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• v.7 no.5
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• pp.373-379
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• 2013

The consumption of fruits and vegetables that have high polyphenol content has been previously associated with a reduced risk for cardiovascular disease. We investigated the effects of onion peel extract on plasma total antioxidant capacity, lipid peroxidation, and leukocyte DNA damage. This study was a randomized, double-blind, placebo-controlled, crossover trial. Healthy female subjects received either onion peel extract or placebo (dextrin) for two weeks, underwent a 1-week washout period, and then received the other treatment for an additional two weeks. After two weeks of onion peel extract supplementation, the total cholesterol level, low-density lipoprotein cholesterol level, and atherogenic index significantly decreased (P < 0.05). No changes were observed in activities of erythrocyte antioxidant enzymes or levels of lipid peroxidation markers following onion peel extract supplementation. Additionally, no significant difference was found in plasma antioxidant vitamin (retinol, tocopherols, carotenoids, and coenzyme Q10) levels or ex vivo $H_2O_2$-provoked oxidative DNA damage after onion peel extract supplementation. The present interventional study provides evidence of the health benefits of onion peel extract and demonstrates its effects in modulating lipid profiles in healthy young Korean women.

• Nutritional Sciences
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• v.7 no.3
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• pp.133-137
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• 2004

The present study was designed to investigate the effects of genistein, daidzein, and quercetin on the antioxidative systems of normal rats. Male Sprague-Dawley rats were divided randomly into seven groups and treated with flavonoids at either 2 or 20 mg/day or through vehicle for four weeks. Lipid peroxidation in the liver was inhibited significantly following administration of quercetin. Genistein and daidzein did not have significant effects except in rats treated with 20mg daidzein/day. Genistein and daidzein treatment did not affect the content of $\alpha$-tocopherol in the serum and liver, while quercetin caused a slight increase. In hepatic glutathione and its related enzymes, genistein and daidzein treatment tended to cause a decrease in $\alpha$-tocopherol content, although no significant difference was found. However, quercetin treatment significantly decreased the content of glutathione together with the activity of glutathione reductase in all doses in the liver but there was no significant difference in the brain. Interestingly, daidzein treatment in the brain at 2mg/day significantly increased glutathione (27.1% p＜0.05) compared with the control group, while at 20mg/day glutathione decreased significantly (26.6%, p＜0.05). In conclusion, genistein has not antioxidant effects. Daidzein quercetin may have the capacity to produce not only antioxidants but also have adverse effects including the production of pro-oxidants. Therefore, people should consider consumption at a high dosage.

• The Korean Journal of Food And Nutrition
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• v.29 no.6
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• pp.829-834
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• 2016

Free radicals originate due to the radiolysis of cytoplasmic water with low "Linear Energy Transfer" (LET) radiations. Naringenin (Ng) is a natural antioxidative compound found in citrus fruits. This study revealed that Naringenin (Ng) reduced the radiation damage of critical organs by scavenging oxidative free radicals. In the study, Ng was orally administrated to rats daily for 7 consecutive days, prior to whole body exposure to gamma-rays. The scavenging efficacy was evaluated biochemically by measuring the concentration of cytotoxic byproducts and the activity of enzymes relevant to oxidative free radicals, after extracting the organs from the exposed rat. We observed increased levels of malondialdehyde (MDA) concentration, and decrease in the activities of superoxide dismutase (SOD) and catalase (CAT) in the exposed control group. However, pretreatment with Ng significantly reduced the MDA concentration, and increased the activities of SOD and CAT, as compared to the control group, due to the free radical scavenging by Ng. The results indicate that Ng administration prior to irradiation could protect critical organs from radiation damage.

• Food Science and Biotechnology
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• v.15 no.2
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• pp.227-231
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• 2006

Strain NK181 was isolated for probiotic use from jeotkal and based on results of API 50 CHL kit and 16S rDNA sequencing was tentatively named Lactobacillus plantarum NK181. L. plantarum NK181 was highly resistant to artificial gastric juice (pH 2.5) and bile acid and demonstrated strong adherence to Caco-2 cells. In test using API ZYM kit, eight enzymes were produced. Supernatant of L. plantarum NK181 exhibited about 30% 1,1-diphenyl-2-picyryl hedrazyl (DPPH) radical-scavenging activity and reduced cholesterol by 70%. These results demonstrate potential use of L. plantarum NK181 as health-promoting probiotic.