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        검색결과 18

        3.
        2008.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        배관 내부의 방사성 오염도를 측정하기 위한 ZnS(Ag)/플라스틱섬광체 조합의 알파/베타선 동시측정용 phoswich 검출기를 개발하였다. 알파/베타선 동시측정용 phoswich 검출기의 오염위치에 따른 검출 성능을 PSD (Pulse shape discrimination) 방법을 이용하여 평가하였다. 또한, 검출기를 방사성 오염물질로부터 보호하기 위한 오염방지용 필름에 대한 방사선 감쇄 정도를 실험적으로 평가하였다. PSD 방법으로 알파/베타선 분리 정도를 측정한 결과 충분히 알파와 베타선이 분리되었으며 오염방지용 필름의 적용 가능성을 확인하였다.
        4,000원
        4.
        2017.04 KCI 등재 서비스 종료(열람 제한)
        Bisphenol A (BPA), a known endocrine disruptor, induces toxicity in cells and in experimental animals. Ginseng extracts were evaluated to determine whether they can inhibit BPA-induced toxicity. The antioxidant activity of fresh ginseng extract (WGE), dried white ginseng extract (DGE), and dried red ginseng extract (RGE) was measured using the DPPH assay. WGE and RGE increased DPPH free radical scavenging activity. Cell viability was measured in HepG2 cells following treatment with BPA and ginseng extracts using the MTT assay. DGE and RGE increased HepG2 cell viability following treatment with 200 μM BPA. RGE reduced levels of biochemical markers of liver damage, aspartate aminotransferase (AST) and alanine aminotransferase (ALT) that increased in mice following treatment with BPA. In addition, the regeneration and proliferation of damaged liver cells were significantly increased in RGE-treated mice. Moreover, RGE inhibited hepatic fibrosis in the surrounding area and in the central vein of the liver microstructure. RGE also significantly inhibited BPA-induced cytotoxicity. In addition, RGE protected liver damage and regenerated liver tissues in BPA-treated animals. These results show that RGE may represent a potential candidate drug for the treatment and prevention of liver damage caused by environmental toxins.
        5.
        2017.02 KCI 등재 서비스 종료(열람 제한)
        Background: Ganoderma lucidum cultured on hulled barley was investigated as a potential natural source of antioxidants and antiinflammatory agents. Methods and Results: The yields from Ganoderma lucidum cultured on hulled barley water and ethanol extract were 17.69% and 25.77%, respectively. The antioxidant activity of Ganoderma lucidum cultured on hulled barley extracts was confirmed by various methods including assayss of 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2-azino-bis-(3-ethylbenzo thiazoline-6-sulfonic acid) (ABTS), nitrite radical scavenging, and Fe3+ to Fe2+ reducing power activity. The ethanol extract of Ganoderma lucidum cultured on hulled barley showed improved DPPH, ABTS and nitrite radical scavenging activity compared with the water extract. After treatment of RAW264.7 cells with Ganoderma lucidum cultured on hulled barley ethanol extracts, the cell viability compared with the control was 92.82%, even at a concentration of 3,000 ㎍/㎖. The ethanol extract inhibited reactive oxygen species (ROS) generation in RAW264.7 cells stimulated with H2O2, even at low concentrations. In addition, the ethanol extract showed an inhibitory effects on the production of lipopolysaccharide-induced nitric oxide (NO) in RAW264.7 cells. Conclusions: This study suggests that the extract of Ganoderma lucidum cultured on hulled barley is a potential source of natural antioxidants and anti-inflammatory agents.
        6.
        2016.10 서비스 종료(열람 제한)
        Background : Lactuca sativa (LS) is a member of lactuca genus and the Asteraceae family. To its usual purpose as an edible leafy vegetable, lettuce has had a number of uses in ancient times as a medicinal herb. Depending on the variety, lettuce is an excellent source vitamin K and vitanin A. Methods and Results : The objective of this study is to find out the antioxidant and oxidative DNA damage prevention capacity of LS for both water and ethanol extract. The total phenolic and flavonoid contents have been estimated in this study. The extracts have been tested to assess the 1, 1-diphenyl-2-picryl-hydrazyl (DPPH), 2,2ʹ -azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) and nitrite scavenging activity. We have also evaluated the reducing power activity of LS. LS extracts showed a good radical scavenging activity on DPPH and ABTS free radical as concentration dependent manner. The IC50 values on DPPH radical scavenging activity were 0.75 mg/mL and 0.54 mg/mL for water and ethanol extract respectively. ABTS radical scavenging activity ranges from 38-89 % for water extract and 33-96% for ethanol extract. Although ethanolic extract showed a higher radical scavenging activity as compared to the water extracts. All the extracts exhibited reducing power activity, dose dependently. Moreover, when the DNA was treated with the extracts, supercoiled DNA was restored in a concentration-dependent manner. Conclusion : According to the results, we suggest that LS contains considerable amount of phenolic and flavonoid content and could be used as a source of natural antioxidant substances and oxidative DNA damage preventer.
        7.
        2016.10 서비스 종료(열람 제한)
        Background : Achyranthes japonica Nakai (AJ) is a perennial herb with a wide distribution in East Asia including Korea, China, and Japan, and it is mainly used as a medicinal plant. In Korea, AJ has been widely used to control pain and improve symptoms in OA patients. AJ contains several important phytochemicals such as saponins, inokosterone, ecdysterone, and oleanolic acid bisdesmoside. Methods and Results : The aim of this work was to investigate the antioxidant and anti-inflammatory activities of fermented and ethanol extracts of Achyranthes japonica Nakai (AJ). The extracts showed strong reductive power and nitrite scavenging, hydroxyl radical scavenging, superoxide radical scavenging, and DNA damage prevention activities. Treatment of RAW 264.7 macrophages with AJ inhibited lipopolysaccharide (LPS)-induced NO secretion and iNOS expression without affecting cell viability. AJ also inhibited cyclooxygenase 2 (COX-2) expression, leading to the suppression of COX-2-derived prostaglandin E2 production. These inhibitory effects of AJ were accompanied by reduced production of tumor necrosis factor-α and interleukins (IL)-1β, -6, and -10. Furthermore, AJ suppressed LPS-induced phosphorylation of extracellular signal regulated kinase, c-Jun N-terminal kinase, and p38. Moreover, AJ inhibited malondialdehyde production and myeloperoxidase activity in LPS-stimulated RAW 264.7 cells. Conclusion : The antioxidant activity of plants is closely related to their medicinal properties and is widely used as a parameter to determine the bioavailability of medicinal plants. The antioxidant and biological activities of AJ extracts might be due to the synergistic actions of multiple bioactive compounds. It can be concluded that AJ extracts are a potential source of biologically important drug candidates.
        8.
        2016.10 서비스 종료(열람 제한)
        Background : ROS produced by oxidative stress damaged endothelial cells, and cause a variety of vascular complications. In diabetic hyperglycemia state, ROS increase. The polyol pathway occur in diabetic complications, the excess glucose is absorbed into the polyol pathway when aldose reductase increased, NADPH changes it to sorbitol. Glutathione (GSH) removes ROS. GSH level is reduced by glutathione reductase, using NADPH as an electron donor. Activation of the polyol pathway decrease NADPH, and GSH also reduced. As a result, ROS is increased. In diabetic hyperglycemia state, Glycolysis increases. Effects of increased glycolysis, protein kinase C (PKC) is increased. NAD(P)H oxidase, stimulated by PKC-dependent pathway, increases ROS in the cell. In this study, we measured the ROS scavenging activity of 5 natural products (Lycii fructus, Astragalus membranaceus, Cassia Tora, Polygonatum odoratum, Rubus Coreanus), to confirm the efficacy as diabetic antioxidants. Methods and Results : We extracted 5 natural product by distilled water and ethanol. DPPH radical scavenging activity was significantly higher in Lycii fructus, Rubus coreanus. ABTS radical scavenging activity was better Rubus coreanus, Lycii fructus, Cassia Tora. In addition to, Rubus coreanus, Cassia Tora, Lycii fructus was comparatively higher reducing power activity than other natural products. And total phenolic and flavonoid contents were much higher in Rubus coreanus compared with other extracts. Conclusion : These results suggest that Lycii fructus, Rubus coreanus can be applied as diabetic antioxidant that prevent vascular complications caused by ROS.
        9.
        2016.05 서비스 종료(열람 제한)
        Background : Dioscorea quinqueloba(DQ) is a medicinal herb that is used as an alternative therapy for cardiovascular disease and various medical conditions. The objective of this study was to characterize the antioxidant activities of DQ. Methods and Results : The samples were extracted with Distilled water and analyzed for total flavonoid contents, polyphenol contents, DPPH radical scavenging activity, and ABTS radical scavenging activity. H9c2 cardiomyoblast cells were subjected to H2O2, to study the protective effect of DQ on cell viability, and ROS production. The total amounts of polyphenols and flavonoids, which indicate the antioxidant capabillity of water extracts from DQ were 27.21mg/g and 22.95mg/g, respectively. The DQ water extract showed highest antioxidant activity by DPPH and ABTS scavenging activities. The DQ water extract was protected cells against H₂O₂-induced cell death without any cytotoxicity, as determined by the MTT assay. The DQ water extract also was inhibiting production of intracellular ROS. Conclusion : These observations suggest that DQ can use potentially good natural antioxidant in daily life for possible health benefits.
        10.
        2016.05 서비스 종료(열람 제한)
        Background : Osteoclasts as multinucleated cells originate from hematopoietic monocyte/ macrophage precursor cell, shows the bone absorption through the commitment, differentiation, fusion, and bone resorption stages by regulation of M-CSF and RANKL. It has been reported a significant negative correlation between the increase of oxidative stress and the bone density, and when RANKL reaction to the osteoclasts precursor cells is mainly generated ROS is due to increased activity of NADPH oxidase1 (NOX1), and these ROS act as a factor which promotes osteoclasts differentiation. Thus, RANKL signaling process is important that excessive osteoclast formation and differentiation inhibited through the regulation of each step. Methods and Results : F3570 ethanol extract showed relatively high activity at in-vitro antioxidant activity. F3570 water extract inhibited ROS generation in RAW 264.7 cells stimulated with H2O2 and RANKL, even at low concentrations. The inhibitory effect of osteoclast differentiation on F3570 water extract was confirmed that shown through NF-κB pathway, MAPK pathway including ERK and JNK. F3570 ethanol extract is considered to be regulated by the p38 MAPK and the other signaling pathway. Also, F3570 both water and ethanol extract were significantly reduced gene expression such as TRAP, calcitonin receptors and integrin β3 of RANKL-induced mature osteoclast in the bone resorption stage. Conclusion : Through this study, F3570 extract revealed an outstanding inhibitory effect and signaling mechanisms in osteoclast differentiation induced by RANKL. These results suggest that F3570 is bone diseases associated with aging or osteoporosis caused by menopause in an aging society is expected to be a superior candidate for the treatment or the prevention