• Natural Product Sciences
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• v.5 no.4
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• pp.165-171
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• 1999

Since reactive oxygen species (ROS) play an important role in carcinogenesis and other several human diseases, antioxidants present in consumable fruits, vegetables, and beverages have received considerable attention as cancer chemopreventive agents. Thus, in order to identify antioxidants in plant extracts, potential activity was assessed by determining with inhibition of a xanthine/xanthine oxidase assay system. Approximately 170 plant extracts of Korean herbal medicines were primarily evaluated for the potential of antioxidant activity. As a result, 13 plant extracts were found to be active $(IC_{50}$<$100\;{\mu}g/ml)$. Especially, Juncus effusus, Selaginella tamariscina, Pueraria thunbergiana and Sedum albroseum showed strong inhibitory activity in this process. Further studies for the identification of active principles from these active lead plant extracts might be warranted.

• Archives of Pharmacal Research
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• v.21 no.1
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• pp.1-5
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• 1998

Rebamipide, 2-(4-chlorobenzoylamino)-3-[2(1H)-quinolinone-4-yl]-propionic acid, a novel antipeptic ulcer agent, has been reported to prevent various acute experimental gastric mucosal lesions and to accelerate the healing of chronic ulcers. Therapeutic effect of rebamipide was investigated with regard to the inhibitory effect on xanthine oxidase activity and type conversion of the enzyme which play a profound role in oxygen radicals generation system. Intraperitoneal administration of rebamipide at 60 mg/kg body weight reduced the xanthine oxidase activity, lipid peroxide content in ammonia induced hemorrhagic lesion. These results suggest that the therapeutic effect of rebamipide on gastric mucosal lesion may be in part due to the inhibitory activity of xanthine oxidase and type conversion rate of the enzyme.

• Journal of the Korean Chemical Society
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• v.36 no.2
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• pp.335-337
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• 1992

• Journal of Physiology & Pathology in Korean Medicine
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• v.16 no.5
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• pp.955-959
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• 2002

To test the protective effect of herbal medicine on myocardial damage against oxygen free radical-induced myocardiotoxicity, cytotoxicity was examined using MTT, Beating rate and TSARS assay in the presence of water extract of Rhizoma Coptidis. Myocardial toxicity was evaluated in neonatal rat myocardiocytes in cultures. The results of these experiments were obtained as follows: Xanthine oxydase/hypoxanthine resulted in a decrease in viability, beating rate and in a increase in lipid peroxidation in Cultured myocardial cells. Rhizoma Coptidis water extract shows effects of protection from the cardiocyte toxicity induced by xanthine oxydase/hypoxanthine treatment such as increases in beating rate. Rhizoma Coptidis water extract shows effects of protection from the cardiocyte toxicity induced by xanthine oxydase/hypoxanthine treatment such as decreases in lipid peroxidation. These results show that xanthine oxydase/hypoxanthine elicits toxic effects. in cultured myocardial cells derived from neonatal rat, and suggest that water extract of Rhizoma Coptidis is very effective in the prevention of xanthine oxydase/hypoxanthine-induced cardiotoxicity.

• Journal of Physiology & Pathology in Korean Medicine
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• v.16 no.6
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• pp.1117-1121
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• 2002

To test the protective effect of herbal medicine on myocardial damage against oxygen free radical-induced myocardiotoxicity, cytotoxicity was examined using MTT, Beating rate and DNA synthesis assay in the presence of water extract of three kinds of Radix Rehmanniae. Myocardial toxicity was evaluated in neonatal rat myocardiocytes in cultures. The results of these experiments were obtained as follows : Xanthine oxydase/hypoxanthine resulted in a decrease in viability, beating rate and DNA synthesis in cultured myocardial cells. Radix Rehmanniae Recens(生地黃, RRR) water extract shows effects of protection from the cardiocyte toxicity induced by xanthine oxydase/hypoxanthine treatment such as increases in beating rate. Radix Rehmanniae Preparat(熟地黃, RRP) water extract shows effects of protection from the cardiocyte toxicity induced by xanthine oxydase/hypoxanthine treatment such as increases in DNA synthesis. These results show that xanthine oxydase/hypoxanthine elicits toxic effects in cultured myocardial cells derived from neonatal rat, and suggest that water extract of three kinds of Radix Rehmanniae is very effective in the prevention of xanthine oxydase/hypoxanthine-induced cardiotoxicity.

• Journal of the Korean Society of Food Culture
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• v.18 no.5
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• pp.443-456
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• 2003

The lyophilization of the solution extracted from 60 percent of acetone applied to persimmon leaves, the compounding process in accordance with the solution's concentration, and the gel filteration through Sephadex G-50 of biologically activated substances obstructing enzyme activity, such as tyrosinase, xanthine oxidase, and angiotesin converting enzyme (ACE) led to the assumption that polyphenol was the compound serving as biologically activated substances obstructing enzyme activity. Xanthine oxidase involved in pruine metabolism oxidizes hypoxanthine to xanthine and xanthine to uric acid. In the continuous study for natural compound, nine flavan-3-ols have been isolated from the persimmon leaves. The structures of (+)-catechin, (+)-gallocatechin, procyanidin B-1, pyrocyanidin C-1, prodelphinidin B-3, gallocatechin-$(4{\alpha}{\rightarrow}8)$-catechin, procyanidin B-7-3-O-gallate, procyanidin C-1-3'-3'-3'-O-trigallate and (-)-epigallocatechin-$(4{\alpha}{\rightarrow}8)$-epigallocatechin-$(4{\alpha}{\rightarrow}8)$-catechin were established by NMR and their inhibitory effect on xanthine oxidase activity was investigated. Procyanidin B-7-3-O-gallate, (-)-epigallocatechin-$(4{\alpha}{\rightarrow}8)$-epigallocatechin-$(4{\alpha}{\rightarrow}8)$-catechin and procyanidin C-1-3'-3'-3'-O-trigallate showed 94%, 90.69%, 80.90% inhibition at $100\;({\mu})M$ and inhibited on the angiotensin converting enzyme respectively. Procyanidin B-7-3-O-gallate and procyanidin C-1-3'-3'-3'-O-trigallate showed 66%, 63% inhibition at $100\;({\mu})M$ and inhibited on the xanthine oxidase competitively. Procyanidin C-1-3'-3'-3'-O-trigallate showed 70% inhibition at $100\;({\mu})M$ and inhibited on the tyrosinase competitively.

• Biomedical Science Letters
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• v.1 no.1
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• pp.37-43
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• 1995

To evaluate an effect of xanthine oxidase(XO) reaction system on the carbon tetrachloride($CCl_4$) metabolism, $CCl_4$ was given twice at 0.1ml/100g body wt. at intervals of 18 hour to the rats and those pretreated with allopurinol (50mg/kg. body wt.). The influence of XO on the metabolism of $CCl_4$ was focused on the degree of liver damage and the activities of a $CCl_4$ metabolizing marker enzyme, glucose-6-phosphatase. The increasing rate of liver weight per body weight and the levels of serum alanine aminotransferase to the control group were more decreased in allopurinol-pretreated rats than in those treated with $CCl_4$ alone. The liver XO activities were more increased in $CCl_4$-treated rats than the control group and the $CCl_4$-treated rats pretreated with allopurinol showed a decreased activities of XO compared to the $CCl_4$-treated rats. The type conversion (type D --> type O) rate was more decreased tendency in allopurinol pretreated rats than those treated $CCl_4$ alone. In dialyzed liver enzyme preparations, all of the xanthine oxidase activities: $CCl_4$-treated, allopurinol and $CCl_4$-treated rats pretreated with allopurinol showed the more increased Vmax value than the control group, but similar Km value. Moreover, $CCl_4$-treated rats pretreated with allopurinol showed the more increased Vmax value than the group treated with $CCl_4$ alone. In conclusion, it can not be negate the possibility of metabolism of $CCl_4$ by the xanthine oxidase enzyme system.

• Journal of the Korean Society of Food Science and Nutrition
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• v.22 no.4
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• pp.392-397
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• 1993

The present work was undertaken to investigate the protective mechanism of Oenanthe iavanicu n-butanol extract on the carbon tetrachloride-induced hepatotoxicity in mice. It was observed that a striking enhancement of serum alanine aminotransferase and hepatic lipid peroxide content after carbon tetrachloride administration were markedly decreased by the presentment of Oenanthe javanica extract for 5 days. It was also observed that the hepatic aniline hydroxylase, catalase, glutathione S-transferase activity and glutathione content were not changed by the injection of Oenanthe javanica extract for 5 days. Whereas, hepatic xanthine oxidase activity was inhibited by the treatment of Oenanthe javanica extract for 5 days. After treatment with Oenanthe javanica extract, xanthine oxidase activity was decreased with dose and time-dependent manner as compared to control group. However, hepatic xanthine oxidase activity was not affected by the addition of Oenanthe javanica extract in vitro. These results suggest that the inhibition of hepatic xanthine oxidase activity by the injection of Oenanthe javanica extract is believed to be a possible protective mechanism for the carbon tetrachloride-indured hepatotoxicity in mice.

• Korean Journal of Oriental Medicine
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• v.5 no.1
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• pp.111-117
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• 1999

Free radicals are thought to be the most important cause of the reperfusion injury subsequent to ischemia. The antioxidant status of the tissue affected by ischemia-reperfusion is of great importance for the primary endogenous defense against the free radical induced injury. Therefore, antioxidant therapy has been shown to be beneficial in neurological disorders such as Alzheimer's disease and cerebral ischemia. In this study, the protective effects of Chungpesagan-tang (CST) was investigated against ischemia/reperfusion-induced cytotoxicity in SK-N-MC neuronal cells It was found out that low concentration of CST was highly effective in protecting neuronal cells against ischemia/reperfusion-induced cytotoxicity. The inhibitory effect of CST on malondialdehyde formation during ischemia/reperfusion-induced oxidative stress in SK-N-MC cells showed obvious dose-dependent responses. Also, CST showed relatively high inhibitory activity to xanthine oxidase induced by ischemia/reperfusion environment Therefore, it is thought that CST has both antioxidant and xanthine oxidase inhibitory effect and can be used for clinical applications for protection of neuronal cells from ischemia-reperfusion injury.

• The Korean Journal of Pharmacology
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• v.19 no.2
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• pp.35-44
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• 1983

reactive oxygen species에 의해 나타나는 reactivity에 있어서 metal ions이 관여함이 시사되고 있다. 이미 알려진 reactive oxygen species와 metal ions의 상호작용 이외에 특히 $Cu^{++}$과 $H_2O_2$가 강력한 peroxidative action을 나타낸다는 사실이 알려져 있으며 $Cu^{++}-H_2O_2$가 biological system 에서의 조직파괴에 관여할 가능성이 저자들에 의해서 효소 및 조직치 구조 단백질의 gradation 효과를 관찰함으로써 시사되었다. 본 연구는 $H_2O_2$ 혹은 $H_2O_2$를 생성하는 효소계(xanthine과 xanthine oxidase 및 glucose과 glucose oxidase)에 $Cu^{++}$을 첨가하여 $Cu^{++}-H_2O_2$에 의한 peroxidation의 효과를 collagen gelation을 통하여 확인코저 수행하였으며 다음과 같은 결과를 얻었다. 1) $Cu^{++}(20\;{\mu}M)$과 $H_2O_2$에 의하며 collagen gelation은 현저히 억제되었으며 이같은 억제효과는 양자의 농도에 비례하였다. 2) $Cu^{++}-H_2O_2$ reactivity를 확인하는 다른 방법으로 glucose oxidase system를 이용하였다. glucose oxidase$(2.5{\mu}g/ml)$ 와 glucose(0.5 mM)는 collagen gelation에 영향을 미치지 않았으나 이에 $Cu^{++}$이 존재하면 gelation이 억제되었다. 이때 억제정도는 $glucose(0.125{\sim}l.25\;mM)$와 $Cu^{++}$의 농도에 비례하였다. 3) 여러 reactive oxygen species 가운데 $Cu^{++}-H_2O_2$ reactivity를 xanthine oxidase system을 이용하여 확인하였다. (a) collagen gelation은 xanthine oxidase(30 munits/ml)와 xanthine$(0.25{\sim}2\;mM)$에 의하여 억제되었다. (b) 이때 나타나는 collagen gelation의 억제는 superoxide dismutase에 의하여 완전히 회복되었으나 catalase에 의해서는 더욱 촉진되었다. 그러나 catalase에 의한 억제효과의 촉진은 1,4-diazabicyclo(2,2,2)octane에 의하여 완전히 소실되었다. 따라서 이 xanthine oxidase system에서는 $O_2-,\;H_2O_2,\;^1O_2$이 관여함을 알 수 있었다. (c) 그러나 $Cu^{++}(10\;{\mu}M)$이 존재하였을 때 collagen gelation은 superoxie dismutase에 의해 더욱 억제되었고 catalase에 의해서는 완전히 회복되었다. xanthine oxidase계에서 얻어진 결과는 여러 reactive oxygen species가운데 $H_2O_2$가 $Cu^{++}$에 의하여 peroxidation효과를 나타냄을 알 수 있었다. 이상의 결과로 미루어 볼 때 reactive oxygen species와 metal ions과의 상호작용 가운데 $Cu^{++}-H_2O_2$는 강한 반응을 나타내는 특이한 구성요소이고 헌재 시사되고 있는 reactive oxygen species의 biological effects에 비추어 $Cu^{++}-catalyzed peroxidation$도 병적상태에서 생체에 유해한 작용을 나타내는 요소임을 시사하며 특히 염증시 조직파괴역할에 관하여 고찰하였다.