• 전기의세계
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• 제22권4호
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• pp.30-34
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• 1973

The main purporse of this paper is to study on the influence of temperature effect on electrical-properties, i.e., dielectric breakdown voltage, dielectric constant and resitivity of homemade insulating oil containing antioxidant. Transformer oil manufactured in Korea is taken for a sample, and this sample is classified into seven samples in which antioxidant is contained and not contained, and antioxidant is divided into three kinds of amount: 0.3%, 0.5%, 0.8%. Changing the tempe5rature of the samples by oil bath, the electric properties measured from the samples are as follows: (1) the variation of either the dielectric breakdown voltage or the resistivity are considerably large, but the dielectric constants are almost unchanging. (2) In view of electrical characteristic, the deterioration rate of the samples containing antioxidant is somewhat lower than that of other samples. (3) Nearly the same value is shown in the dielectric-breakdown voltage of the samples, in which contained the different amount of antioxidant: 0.3%, 0.5%, 0.8%, but the decrease rate of resitivity is lowest, 0.3%, of all. As the result of the experiment, This study can suggest that 0.3% be the optimum amount of antioxidant which will be added transformer oil manufactured in Korea and is useful for the understanding about the electrical properties of transformer oil containing antioxidant.

• Elastomers and Composites
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• 제17권1호
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• pp.13-21
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• 1982

The purpose of this dissertation is to compare bound andtioxidant, MHPPD with the ordinary one, IPPD, when high polymers are used like NR and SBR. The effect of rubber bound antioxidant and ordinary antioxidant on the Mooney scorch time has been studied by means of the Mooney viscometer. The ageing properties of vulcanizates containing rubber-bound antioxidant and ordinary antioxidant have been studied in terms of hardness, tensile strength and elongation. The results of the Mooney scorch time and ageing properties are as follows: When MHPPD was mixed with NR or SBR compounds, the Mooney scorch time was faster than the IPPD compounds. Also the ageing properties of the vulcanizates containing MHPPD were much superior to the IPPD compounds. Furthermore, the vulcanizates comporised of MHPPD have taken andvantage of and resistance in the ozone test.

• Natural Product Sciences
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• 제25권2호
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• pp.143-149
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• 2019

Eucommiae Cortex (EC), bark of Eucommia ulmoides, has been known as a traditional medicine to regulate hypertension and immune system. Because silk of gum in the EC blocks the release of active ingredients, EC generally has been utilized after processing with carbonization or salt-water to breakdown it. This study aimed to investigate the differences of non-processed EC and processed EC on antioxidant and anticancer properties. Antioxidant capacity was assessed by measuring the content of total polyphenols, reducing power, and ABTS radical scavenging effect. And anticancer effects were examined by evaluating the viability of pancreatic cancer cells and wound healing ability. The results demonstrated that processed EC contained more content of polyphenols and exhibited more potent reducing power and radical scavenging effect than non-processed EC. In addition, processed EC more efficiently inhibited proliferation and migration of pancreatic cancer cells. These results suggest that processing of medicinal plants can improve the biological properties such as antioxidant or anticancer activity, which may lead to the development of herbal medicine treatment technology.

• 한국축산식품학회지
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• 제38권5호
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• pp.889-900
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• 2018

Characterization and utilization of the bioactive compounds from natural resources is one of the most concerns to maintain quality properties of foods, especially to prevent the oxidation of lipids in meat products. Phytochemical components and antioxidant activities of Cudrania tricuspidata (CT) leaves extracted using various solvents and their effects on physicochemical properties of pork patties during refrigerated storage were measured. The combined solvents of 80% ethanol, 80% methanol and pure double-distilled (dd)-water obtained the higher total phenolic compounds, flavonoids content, and antioxidant activities as compared to the pure solvent alone. Among the individual antioxidant components, catechin was the predominant polyphenol in CT leaves in all extracts. The addition of CT leaves extracts into pork patties showed high antioxidant activities since thiobarbituric acid-reactive substances (TBARS) values of added CT extracts were lower than those of the control (p<0.05). In conclusion, CT leaf phytochemical components displayed antioxidant activity that varied with the extract solvent used. CT extracts were superior to control in retarding lipid oxidation of pork patties, which was evident as reduced TBARS and peroxide values (POV).

• 대한의생명과학회지
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• 제24권3호
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• pp.196-205
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• 2018

Reactive oxygen species (ROS) generated from metabolic reactions cause oxidative DNA damage, which results in oxidative tissue injury. Therefore, there is an increasing demand in the intake of high antioxidant sources in order to maintain a healthy environment in cells. In this study, we investigated the antioxidant and anti-inflammatory activities of Malus domestica (apple), Pyrus communis L. (pear), Daucus carota L. (carrot), Brassica oleracea var. (broccoli), Brassica oleracea var. capitata (cabbage), and Raphanus sativus L. (radish) obtained from the local market. Since these are common fruits and vegetables that are widely consumed, we aimed to investigate their beneficial properties, placing particular emphasis on their antioxidant and anti-inflammatory properties. The samples were processed via an indirect heating method and their properties were compared to their raw forms. Based on DPPH and ABTS assays, processed samples showed better antioxidant activities when compared to raw samples and processed pear samples exhibited the best antioxidant activity. The anti-inflammatory activities of the samples were also investigated in LPS-treated RAW 264.7 cells. mRNA expression of pro-inflammatory mediators and cytokines (iNOS, COX-2, $TNF-{\alpha}$, $IL-1{\beta}$, and IL-6) was assessed using RT-PCR. As expected, processed samples exhibited better iNOS inhibition when compared to their raw forms and processed broccoli and cabbage samples exhibited outstanding anti-inflammatory effects. The samples, up to 1 mg/mL concentration, did not exhibit cytotoxicity against RAW 264.7 cells as demonstrated by cell viability assays. Altogether, processed broccoli and cabbage samples exhibited the strongest anti-inflammatory properties.

• Preventive Nutrition and Food Science
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• 제21권4호
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• pp.355-360
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• 2016

The influence of extraction temperature, powder concentration, and extraction time on the antioxidant properties of aqueous ginger extract was investigated. The possibility of estimating the antioxidant properties of the extract from its absorbance and colour properties was also investigated. Results indicated that powder concentration was the most significant factor to consider in optimizing antioxidant extraction. However, temperature and time still influenced the 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging activity while extraction temperature influenced the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity of the extract. Using the total phenol content, total flavonoid content, ABTS radical scavenging activity, and DPPH radical scavenging activity of the extract, the multiresponse optimization condition for extraction of antioxidant based on the experimental range studied is $96^{\circ}C$, 2.10 g/100 mL, and 90 min. The absorbance of the ginger extract at 610 nm could be exploited for rapid estimation of its total flavonoid and polyphenol with a $R^2$ of 0.713 and 0.753, respectively.

• Horticulture, Environment, and Biotechnology : HEB
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• 제59권6호
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• pp.919-927
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• 2018

To compare the antioxidant properties and flavonols in various parts; dry skin (DS) and edible portion (EP), of 8 red onions (Allium cepa L, ROs), total content of phenolics (TPC), flavonoids (TFC), and anthocyanins (TAC) and DPPH radical scavenging properties were estimated and the content of six flavonols were quantified by HPLC-PDA analysis. The major component of DS and EP of RO was quercetin and quercetin-4'-glucoside, respectively. Score plots of the PCA and PLS-DA were segregated by flavonols content and antioxidant properties according to the EP and DS of ROs. Loading plot of the PCA showed that the quercetin and sum of flavonol content were highly correlated with antioxidant activity of ROs. Therefore, flavonol content and antioxidant activity can be used as markers for distinct parts of ROs.

• Journal of Applied Biological Chemistry
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• 제51권3호
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• pp.111-116
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• 2008

Aralia elata seeds were successively extracted with water, methanol, ethanol, acetone and chloroform. The crude extracts were investigated for antioxidant and antidiabetic activities. The antioxidant properties of various extracts were evaluated by antioxidant tests, such as DPPH free radical-scavenging activity, hydroxyl radical-scavenging assay, metal-chelating activity, lipid peroxidation inhibition activity and reducing power assay. The 70% methanol extract exhibited the highest activity in the in vitro models of DPPH free radical-scavenging activity, metal-chelating activity, and reducing power assay. Acetone extract showed good effects on lipid peroxidation inhibition and hydroxyl radical-scavenging assay at a low concentration. In addition, the $\alpha$-glucosidase inhibition assay showed that 70% methanol extract had the highest activity. These results indicate the high possibility of using A. elata seeds for medical application due to their efficient antioxidant properties.

• Bulletin of the Korean Chemical Society
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• 제33권10호
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• pp.3343-3348
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• 2012

The possible ways for increasing the antioxidant properties of vitamin E have been investigated with density function theory. The effect of replacing three methyl groups of vitamin E with various substituents such as electron donating and electron withdrawing groups on the antioxidant properties of vitamin E were investigated. Also the effects of the reducing the number of atoms in the heterocyclic ring and replacing the oxygen heteroatom with other heteroatoms on the antioxidant properties of vitamin E were investigated. The novel structures that obtained from replacing methyl groups with substituents such as $NH_2$, OH, COOH and NHMe have greater antioxidant activity than vitamin E. Obtained results reveal that novel structure that obtained with replacing O with NH hetroatom would be a better antioxidant than vitamin E. The results reveal that reducing the number of atoms in the heterocyclic ring is a better way to synthesize novel antioxidants.

• Journal of Microbiology and Biotechnology
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• 제19권11호
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• pp.1333-1341
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• 2009

Haematococcus pluvial is, a green alga, accumulates astaxanthin (3,3'-dihydroxy-$\beta$,$\beta$'-carotene-4,4'-dione) upto 2-3% on a dry weight basis. In the present study, identification of carotenoids from Haematococcus cyst cell extract by HPLC and LC-MS (APCI) and their antioxidant properties were evaluated in in vitro model systems. The extract exhibited 89% and 78% antioxidant activities in the $\beta$-carotene linoleate model and the hydroxyl radical scavenging model, at 9 ppm of total carotenoid, respectively. The extract also showed 80%, 85%, and 79% antioxidant activities against lipid peroxidation in the kidney, brain, and liver of rats. Low-density lipoprotein oxidation induced by $Cu^{2+}$ ions was also protected (45%, 64%, and 75%) by the extract in a dose-dependent manner with different carotenoid levels. Thiobarbituric acid reactive substances concentration in the blood, liver, and kidney of rats were also significantly (p<0.005) decreased in H. pluvialis-treated rats. The potent antioxidant activity is attributable to various carotenoids present in the extract.