• 한국환경보건학회지
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• 제28권2호
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• pp.81-88
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• 2002

Effect of cyclohexanone treatment on the activities oxygen free radical and cyclohexanone metabolizing enzyme in acute liver damaged rats, was investigated. Acute liver damage was induced in rats with pretreatment of 50% $CCl_4$ in olive oil(0.1ml/100g body wt) intraperitoneally 3 times every other day. Cyclohexanone(1.56g/kg body wt, i.p.) was administered to the animals 24 hours after the last Pretreatment of CC1$_4$. Rats were sacrificed at 4 hours after injection of cyclohexanone. On the basis of liver weight/body weight(％), serum levels alanine aminotransferase activity and hepatic protein content, cyclohexanone treatment to acute liver damaged animals led to the more enhanced liver damage. On the other hand, injection of cyclohexanone to the rats led to the increased activities of hepatic cytochrome P-450 dependent aniline hydroxylase and xanthine oxidase. Furthermore, by treatment of cyclohexanone to the acute liver damaged rats hepatic xanthine oxidase activity was more increased than the $CCl_4$ treated rats. In case of oxygen free radical scavenging system, the hepatic glutathione content and the activities of hepatic glutathione S-transferase, catalase, superoxide dismutase were generally increased by injection of cyclohexanone to rats, and the hepatic glutathione content, catalase and alcohol dehydrogenase activities were more decreased in liver damaged rats by the treatment of cyclohexanone. In conclusion, the cyclohexanone treatment to acute liver damaged rats led to enhancement of liver damage that may be due to oxygen free radical together with cyclohexanone.

• 생명과학회지
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• 제11권6호
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• pp.509-516
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• 2001

까마중의 부위별 DPPH free radical 소거활성은 뿌리에서 가장 높았고, 줄기, 전부위, 열매 잎 그리고 꽃 순으로 높았다. 추출방법간의 DPPH free radical 소거활성은 80%methanol에 침지하여 추출한것보다는 $80^{\circ}C$에서 80% meth-anol에 흰류추출한것이 높았다. Sephades LH-20 column chromatography에 의하여 분획된 L6의 DPPH free radical 소거활성은 ethy acetate 분획 추출물보다 6.7배 높았다. 분획물내의주요물질은 2, 6-methano-3-benzazocin-11-ol, 2[1h]-pyridinethione 및 2-hydroxy-5 methylbenzaldehyde로 phenolic 화 물이었다. 줄기와 뿌리의 POD및 SOD 활성은 타 부위에 비하여 높은 활성을 나타내었고, 생육기간에는 파종 후 60일후에서 활성이 가장 높았다. PODdmlehddnl gth 패턴은 뿌리에서 10개의 band로 가장 많았고 그중 8개의 band가 식물체의 부위별로 차이가 있어Tdmaul, SOD의 동위효소 패턴은 잎에 5개의 band로 가장 많았고 그중 2개의 band가 식물체의 부위별로 차이가 있었다.이가 있었다.

• 한국해양바이오학회지
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• 제1권4호
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• pp.252-259
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• 2006

본 실험은 electron spin/paramagnetic resonance(ESR/EPR)를 이용하여 기존의 DPPH free radical 소거 활성을 측정하였고, 이를 해조류 유래 천연자원으로부터 새로운 항산화물질을 탐색하는데 적용해 보았다. 연구 결과, 녹조류 추출물에서는 참홑파래, 납작파래 및 청각의 고온 메탄올 추출물에서만 약간의 라디칼 소거활성을 나타내었고, 이 외의 추출물에서는 소거활성이 거의 보이지 않았다. 갈조류는 총 71개의 추출물 중 37개의 추출물에서 80% 이상의 소거율을 보여 아주 우수한 항산화 물질을 가진 family로 여겨지며, 특히 모자반류 (Sargassum spp.)는 수용성과 메탄올, 고온과 상온의 모든 추출물에서 높은 라디칼 소거 활성을 보여 앞으로의 신소재 물질 후보로 선별되었다. 홍조류에서는 수용성보다는 메탄올 추출물에서 대체적으로 높은 소거활성이 검색되어, 나중에는 유기용매 분획물을 제조하여 라디칼 소거능을 측정 할 수 있을 것이다. 이처럼 해조류는 라키칼 소거 능력을 가지는 성분을 여러 형태로 다량으로 함유 하고 있는 것으로 사료 되며 앞으로의 연구에 기대가치를 더해 줄 것으로 사료된다.

• 농약과학회지
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• 제7권2호
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• pp.92-99
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• 2003

96-well plate를 사용해서 DPPH free radical 소거활성의 고효율검정 (high throughput screening)방법을 확립하였고, 이 방법을 이용하여 107개의 식물특정 효소저해제와 다양한 식물 추출물의 항산화활성을 조사하였다. DPPH free radical 소거활성 측정 측정을 위한 적정 시험조건은 총 반응액이 $250{\mu}L$일 경우 $100{\mu}M$의 DPPH(pH 7.8), 20 분의 반응시간이었고, 이 조건하에서 ascorbate와 a-tocopherol 은 농도 의존적인 항산화활성을 나타내었다. 107개의 식물 특정효소저해제 중에서 11개의 화학물질이 $100{\mu}M$ 농도에서 70% 이상의 항산화활성이 있었는데, 특히 ampicillin과 gallic acid는 각각 90.2% 와 92.6% 의 나타냈다. 또한 100개의 식물 추출물은 $50{\mu}g/mL$ 농도에서 70% 이상의 활성을 보이는 추출물이 11개이었는데, 그 중에서 AT-407의 활성이 90.1%로 가장 높게 나타났다. 따라서 96-well plate를 이용한 DPPH free ra 이때 소거활성 측정방법은 여러가지 합성물질이나 다양한 천연물질에 대하여 보다 간편하고 신속하게 항산화활성을 측정할 수 있을 것으로 사료되었다.

• 약학회지
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• 제49권2호
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• pp.174-179
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• 2005

The human skin is constantly exposed to environmental irritants such as ultraviolet, smoke, chemicals. Free radicals and reactive oxygen species (ROS) caused by these environmen tal facts play critical roles in cellular damage. These irritants are in themselves damaging to the skin structure but they also participate the immensely complex inflammatory reaction. The purpose of this study was to investigate the skin cell protective effect of Campsis grandiflora extract on the UVB-irradiated human dermal fibroblasts (HDFs). We tested free radical and superoxide scavenging effect in vitro. C. grandiflora extracts had potent radical scavenging effect by 82% at $100{\mu}g/ml$, respectively. For testing intracellular ROS scavenging activity the cultured HDFs were analyzed by increase in DCF fluorescence upon exposure to UVB 20 $MJ/cm^2$ after treatment of C.grandiflora extracts. The results showed that oxidation of CM-DCFDA was inhibited by C.grandiflora extracts effectively and C.grandiflora extracts has a potent free radical scavenging activity in UVB- irradiated HDFs. In ROS imaging using confocal microscope we visualized DCF fluorescence in HDFs directly. In conclusion, our results suggest that C.grandiflora can be effectively used for the prevention of UV-induced adverse skin reactions such as radical production, and skin cell damage.

• Elastomers and Composites
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• 제50권2호
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• pp.119-125
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• 2015

Because of their low surface free energy and absence of polar groups at the surface, polyolefins are substrates whose wetting and adhesion are very difficult. Free radical grafting of monomers to backbone polymer is one of the most attractive ways for the chemical modification of polymers. Synthesis of graft copolymer through graft polymerizations of PE and/or PP with phthalic anhydride (PhAn) was made and FTIR spectra of the graft polymer were the examined. And also the effects of phthalic anhydride content on the grafting ratio, thermal properties and contact angle of the graft polymer were examined.

• Environmental Analysis Health and Toxicology
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• 제18권3호
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• pp.175-182
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• 2003

Bisphenol A shares similarities in structure, metabolism and action with DES, a known human teratogen and carcinogen. Bisphenol A, a monomer of polycarbonate and epoxy resins, has been detected in canned food and human saliva. The purpose of the this study was to evaluate the cytotoxicity, cell proliferation of bisphenol A In the presence of a rat liver S9 mix, contaning cytochrome P450 enzymes, and Cu (II). In the present study, Bisphenol A in combination with Cu (II) exhibited a enhancement in cytotoxicity which were inhibited by free radical scavengers. The content of malondialdehyde, an end product of lipid peroxidation, was also found to increase with concentration of bisphenol A. Also, we examined the change of CuZn-SOD, Mn-SOD, catalase and GPx activities in the MCF-7 cells exposed to bisphenol A. The activities of CuZn-SOD, CPx, catalase were found to decrease with bisphenol A concentration. Meanwhile, the activity of Mn-SOD was unchanged. This indicated that elevated oxidative stress caused by imbalance between the production and removal of free radicals occurred in cells.

• Natural Product Sciences
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• 제16권3호
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• pp.169-174
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• 2010

The seed of Phaseolus calcaratus Roxburgh (PHCR) is traditionally used for anti-pyretic and antiinflammatory effects. Although these effects are believed to be related to its antioxidant potential, little information is available for the mechanisms by which PHCR seed might scavenge free radicals or otherwise act as an antioxidant. In the present study, we purified some fractions from the ethanol extract of PHCR seed and evaluated each fraction's ability to scavenge free radicals generated by cell-free systems. We also identified active compound that is putatively responsible for free radical scavenging by analyzing NMR spectra. PHCR samples exhibited a concentration-dependent radical scavenging activity against hydroxyl radicals, superoxide anions, and DPPH radicals. Of the samples tested, a methanol-eluted sub-fraction from the PHCR extract, named $FF_4$, scavenged these radicals more effectively than the other fractions. We identified catechin-7-O-$\beta$-Dglucopyranoside as the active compound responsible for free radical scavenging potential of $FF_4$.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2003년도 생물공학의 동향(XIII)
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• pp.794-798
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• 2003

천연추출물로서 미백 재료로 널리 쓰이고 있는 옥용산에 대해서 in vitro 미백활성을 UV 흡수능, tyrosinase 저해활성 그리고 free radical 소거활성을 측정함으로서 검정해 보았다. 옥용산 UV-B와 C 영역에 걸쳐서 높은 자외선 흡수능을 보이는 것으로 관찰이 되었으며 0.8 % 이상의 농도에서 80% 이상의 tyrosinase 저해활성을 가지는 것을 관찰하였다. 또한 조협, 승마, 감송, 정향, 찹쌀분과 옥용산의 추출물은 높은 free radical 소거능을 가지는 것으로 확인되었다.

• Toxicological Research
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• 제17권
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• pp.83-88
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• 2001

Most reactive oxygen species (ROS) are free radicals and implicated in the development of a number of disease processes including artherosclerosis, neurodegenerative disorders, aging and cancer. ROS are byproducts of a number of in vivo metabolic processes and are formed deliberately as part of nor-mal inflammatory response. On the other hand, ROS are generated either as by products of oxygen reduction during xenobiotic metabolism or are liberated as the result of the futile redox cycling of the chemical agents including several chemical carcinogens. A better understanding of the mechanisms of free radical toxicity may yield valuable clue to risks associated with chemical exposures that leading to the development of chronic diseases including cancer. The molecular biology of ROS-mediated alterations in gene expression, signal transduction and carcinognesis is one of the important subjects in free radical toxicology. Epidemiological studies suggest that high intake of vegetables and fruits are associated with the low incidence of human cancer. Many phytopolyphenols such as tea polyphenols, curcumin, resveratrol, apigenin, genistein and other flavonoids have been shown to be cancer chemopreventive agents. Most of these compounds are strong antioxidant and ROS scavengers in vitro and effective inducers of antioxidant enzymes such as superoxide dismutatse, catalase and glutathione peroxidase in vivo. Several cellular transducers namely receptor tyrosine kinase, protein kinase C, MAPK, PI3K, c-jun, c-fos, c-myc, NFkB, IkB kinase, iNOS, COX-2, Bcl-2, Bax, etc have been shown to be actively modulated by phyto-polyphenols. Recent development in free radical toxicology have provided strong basis for understanding the action mechanisms of cancer chemoprevention.