• Journal of Life Science
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• 제13권5호
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• pp.684-691
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• 2003

This study was designed to investigate the effects of ethyl acetate (EtOAc) fraction of pine (Pinus densiflora Sieb et Zucc) needle extract on membrane fluidity (MF), basal and induced oxygen radical (BOR and IOR), lipid peroxide(LPO) and oxidized protein (OP) as an oxidative stress, and lipofuscin(LF) in liver membranes of male Sprague-Dawley rats. Rats were fed basic diets (control) and experimental diets (EtOAc-25, EtOAc-50 and EtOAc-100) for 45days. MFs were significantly increased (about 10%) in mitochondria of EtOAc-100 group compared with control group. BOR and IOR formations in mitochondria were significantly inhibited (about 12∼18% and 9 ∼l2%, respectively) in EtOAc-50 and EtOAc-100 groups, while BOR and IOR formations in microsomes were significantly inhibited (about 9∼l3% and 18∼19%, respectively) compared with control group. LPO levels were significantly inhibited (about 10% and 12∼13%, respectively) in mitochondria of EtOAc-100 and microsomes of EtOAc-50 and EtOAc-100 groups, whereas OP levels were significantly inhibited (about 13∼14%) in mitochondria of EtOAc-50 and EtOAc.-100 groups compared with control group. LF formations were significantly inhibited (about 10∼14%) in these three EtOAc groups. These results suggest that ethyl acetate fraction of pine needle may play an effective role in attenuating an oxidative stress and increasing a membrane fluidity.

• Korean Journal of Food Science and Technology
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• 제43권6호
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• pp.760-765
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• 2011

We investigated the antioxidative effect of black garlic extract (BGE) on paraquat (PQ)- induced oxidative stress in mice. A DPPH radical scavenging activity assay showed that BGE had potent free radical scavenging activity, comparable to that exhibited by vitamin C. Mice were administered with either vitamin C or two levels of BGE by oral gavage for 10 days, with PQ being injected intraperitoneally on day five. It was found that BGE reduced the liver enzyme levels induced by PQ injection in mice. The concentrations of plasma and hepatic malonedialdehyde were both significantly reduced in the BGE groups compared with the levels in the PQ group, whereas the hepatic superoxide dismutase and catalase activities were significantly increased in the BGE groups compared with the PQ group. These findings suggest that BGE has potent antioxidative activities in vivo and thus could prevent the oxidative stress induced by PQ injection in mice by two mechanisms: the induction of antixoxidative enzyme systems and direct scavenging of reactive oxygen species.

• Korean Journal of Plant Resources
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• 제25권2호
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• pp.184-192
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• 2012

The present study was designed to examine the potential antidiabetic and antioxidant effect of ethanol extract from $Prunus$ $mume$ fruit (PME) against alloxan-induced oxidative stress in pancreatic ${\beta}$-cells, HIT-T15. To evaluate the antidiabetic effect of PME, 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazoliu bromide (MTT) cell proliferation assay, lactate dehydrogenase (LDH) release assay, $NAD^+$/NADH ratio and insulin secretion were assessed. We also measured its antioxidant effect against alloxan-induced oxidative stress in the cells by assessing the levels of the antioxidant enzymes including superoxide dismutase (SOD), glutathione S-transferase (GST), glutathione reductase (GR) and glutathione peroxidase (GPx). The results of this analysis showed that alloxan significantly decreased cell viability, increased LDH leakage, and lowered $NAD^+$ /NADH ratio and insulin secretion in HIT-T15 cells. However, PME significantly increased the viability of alloxan-treated cells and lowered LDH leakage. The intracellular $NAD^+$ /NADH ratio and insulin secretion were also increased by 1.5~1.9-fold and 1.4-fold, respectively, after treatment with the PME. The HIT-T15 cells treated with alloxan showed significant decreases in the activities of antioxidant enzymes, while PME significantly elevated the levels of antioxidant enzymes. Based on these results, we suggest that PME could have a protective effect against the cytotoxicity and dysfunction of pancreatic ${\beta}$-cells in the presence of alloxan-induced oxidative stress.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 한국전기전자재료학회 2002년도 춘계합동학술대회 논문집
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• pp.202-205
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• 2002

본 논문은 계속적인 소자의 이용은 전기적인 스트레스까지 야기시키는데, 특히 게이트에 인가되는 전압이나 전류 스트레스는 게이트 산화 막의 열화를 야기 시킬 수 있다. 유리기판위에 저온(${\leq}600^{\circ}C$)공정의 고상결정화을 통하여 다결정 박막 트랜지스터를 제작한 후, 이 소자에 게이트와 드레인에 전압 스트레스를 인가하여 출력 특상과 전달특성을 분석하였는데, 그 결과 다결정 실리콘 박막 트랜지스터의 전달특성은 게이트 와 드레인 전압에 의존하는데 임계전압은 긴 채널길이와 좁은 채널 폭에서 높고 출력특성은 갑자기 높은 드레인 전류가 흐른다. 전기적 스트레스가 인가된 소자는 드레인 전류를 감소시킨다. 결국 전계효과 이동도는 긴 채널길이와 좁은 폭의 채널에서 더 빠른 것을 알 수 있다.

• Korean Journal of Food Science and Technology
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• 제48권3호
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• pp.284-288
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• 2016

To investigate the physiological effect of Hibiscus sabdariffa, in vitro antioxidant activities and neuroprotective effects against high glucose-induced oxidative stress were examined. The ethyl acetate fraction (EtOAc-Fr) from H. sabdariffa contained high total phenolic contents compared with other fractions but total anthocyanin contents were lower than 80% Ethanol extract showed the highest 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt radical scavenging activity and malondialdehyde inhibitory effect. Furthermore, the EtOAc-Fr decreased the intracellular reactive oxygen species level, and protected the neuron-like PC12 cells from high glucose-induced cytotoxicity. The EtOAc-Fr also presented inhibitory effects against acetylcholinesterase as an acetylcholine hydrolase enzyme. Finally, chlorogenic acids as main phenolics by high performance liquid chromatography analysis.

• Journal of the Korean Society of Food Science and Nutrition
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• 제45권7호
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• pp.1057-1064
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• 2016

This study was carried out to investigate the effect of fermented herbal mixtures (FHMs) in HepG2 and PC12 cells. Two different types of fermented herbal mixtures consisted of Chrysanthemum morifolium, Ganoderma lucidum, Acanthopanax senticosus, Schisandra chinensis, Hovenia dulcis thumb, and Lycii fructus. FHM-A and FHM-B were separately fermented with Prunellae Spica, Portulaca oleracea (FHM-A) and Acorus gramineus, Pycnostelma paniculatum (FHM-B). Total phenolic content of FHM-B was higher than that of FHM-A. ORAC values in both FHM-A and FHM-B increased in a dose-dependent manner, and antioxidant activities against peroxyl radicals were higher in FHM-A than FHM-B. Both FHM-A and FHM-B effectively ameliorated AAPH- and ethanol-induced oxidative stress in HepG2 cells. They also suppressed lipid formation induced by ethanol treatment. In addition, FHM-A and FHM-B prevented $H_2O_2$-induced PC12 cell death. FHM-B showed a relatively stronger protective effect than that of FMB-A. Taken together, these findings show that a fermented herbal mixture could be used in healthy and functional food design for oxidative stress-related diseases.

• Journal of the Korean Society of Food Science and Nutrition
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• 제44권3호
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• pp.347-355
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• 2015

Oxidative stress is one of the key mechanisms involved in neuronal damage. Neuroprotective effects and underlying mechanisms of action of several wild vegetables, Cirsium setidens (CS), Pleurospermum kamtschaticumin (PK), and Allium victorials (AV), against oxidative stress induced by hydrogen peroxide in SK-N-SH cells were investigated. CS and AV up to $400{\mu}g/mL$ showed no detectable effects on cell viability of human SK-N-SH neuro-blastoma cells compared with control. Incubation of SK-N-SH cells with hydrogen peroxide resulted in significant induction of cell death and reaction oxygen species (ROS) production, whereas treatment of cells with CS and AV significantly reduced cell death and ROS production, respectively. Among the wild vegetables tested, CS and PK showed more effective DPPH radical scavenging activity than AV, whereas PK showed strong cytotoxicity in SK-N-SH cells compared with the control. CS showed much higher inhibitory effects on cell death and ROS generation against oxidative stress than AV. Thus, CS was selected for subsequent experiments. Ethyl acetate (EA), hexane, butanol, aqueous, and chloroform extracts from CS significantly inhibited cell death and ROS generation in SK-N-SH cells induced by oxidative stress. EA extract from CS (CS-EA) showed the highest DPPH radical-scavenging activity, intra-cellular ROS-scavenging activity, and neuroprotective effects. CS-EA attenuated apoptosis signal-regulating p38 activation by inhibiting phosphorylation. The findings suggest that CS-EA protects neuronal cells through antioxidant activity and inhibition of phosphorylation of p38 in brain neural cells.

• Journal of the Korean Applied Science and Technology
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• 제40권2호
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• pp.223-232
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• 2023

Oxidative stress plays a significant role in the pathogenesis of various skin conditions, resulting in cellular and tissue damage that can contribute to the development of skin tone unevenness, roughness and wrinkles. In this study, we found that Trifolium pratense L. extract (TE) attenuated oxidative-induced damage in HaCaT cells and elucidated the underlying molecular mechanism. Our finding demonstrated that TE effectively protected HaCaT cells against H₂O₂-induced cell death by inhibiting caspase-3 activation, downregulating Bax and upregulating Bcl-2, and attenuating the activation of three mitogen-activated protein kinases (MAPKs). Our results suggest that TE has remarkable cytoprotective properties against oxidative damage in HaCaT cells and could serve as a complementary or alternative approach to prevent and treat skin damage.

• Proceedings of the Korean Vacuum Society Conference
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• 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
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• pp.242.2-242.2
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• 2013

최근 산화물 반도체 박막 트랜지스터의 신뢰성(reliability) 평가에 대한 연구가 활발히 이루어지고 있다. 신뢰성 평가하는 한 방법으로 게이트에 바이어스를 지속적으로 인가하여 소자의 문턱 전압의 변화를 통해 안정성(stability)를 확인한다. 전압을 지속적으로 인가하게 되면 소자를 열화시켜 전기적 특성이 약화된다. 본 연구에선 ITZO 박막 트랜지스터의 신뢰성 평가를 위해 게이트 절연막($SiO_2$, $SiN_x$)에 따른 ITZO 소자를 제작 및 게이트 바이어스 스트레스 후 전기적 특성을 비교, 분석하였다. 제작된 소자의 게이트에 전압을 +15V로 7200초 동안 인가하였다. 스트레스 후 게이트 절연막이 $SiO_2$, $SiN_x$인 ITZO 산화물 박막 트랜지스터 모두 positive 방향으로 이동하였고, 그 결과 문턱 전압, 이동도, 아문턱 기울기의 변화가 발생하였다. $SiO_2$의 경우 아문턱 기울기의 변화가 거의 없이 문턱 전압의 변화만을 보였고, 이는 단순히 ITZO층과 게이트 절연막 계면에 전자가 포획되거나 혹은 게이트 절연막 내에 전자가 주입이 되었기 때문이다. 반면에 $SiN_x$의 경우 ITZO층과 게이트 절연막 계면에 추가적인 결함(defect)이 생성되었기 때문에 $SiO_2$보다 더 많은 전자를 포획하여 아문턱 기울기와 문턱 전압의 변화가 컸다.

• Journal of Food Hygiene and Safety
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• 제13권4호
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• pp.394-399
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• 1998

결명자의 주용성분인 노르-루브로푸사린의 함량이 높은 추출물을 얻기 위하여 결명자분말을 0~100%의 에탄올수용액으로 추출하여 고농도의 노르-루브로푸사린을 함유하는 결명자 추출물을 제조하였다. 결명자추출물과 주요 함유성분인 노르-루브로푸사린은 항산화활성과 프리라디칼소거 작용을 나타내었으며, H2O2 유도 세포독성에 대해서도 억제적으로 작용하여 cyto-protective effect를 나타내었다. 또한 DNA crosslinking agent 인 mitomycin C 유도 소핵생성에도 결명자 70% 에탄올추출물과 노르-루브로파사린이 매우 높은 억제활성을 나타내었다. 따라서 결명자 추출물과 노르-루브로푸사린은 산소라디칼들에 의한 산화적 손상 및 DNA 손상 등에 억제적으로 작용하는 기전을 활용하여 항산화성 스트레스를 통한 항노화 , 암예방제로서의 응용가능성이 높은 물질로 판단되었다.