• Archives of Pharmacal Research
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• v.18 no.3
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• pp.189-194
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• 1995

The focus of this study was to investigate the influences of enzymatic scavengers of active oxygen metabolites and phospholipase $A_2$ inhibitor on hepatic secretory and microsomal function during hepatic ischemia/reperfusion. Rats were pretreated with free radical scavengers such as superoxide dismutase (SOD), catalase, deferoxamine and phospholipase $A_2$ inhibitor such as quinacrine and then subjected to 60 min. no-flow hepatic ischemia in vivo. After 1, 5 hr of reperfusion, bile was collected, blood was obtained from the abdominal aorta, and liver microsomes were isolated. Serum aminotransferase (ALT) level was increased at 1 hr and peaked at 5 hr. The increase in ALT was significantly attenuated by SOD plus catalase, deferoxamine and quinacrine especially at 5 hr of reperfusion. The wet weight-to-dry weight ratio of the liver was significantly increased by ischemia/reperfusion. SOD and catalase treatment minimized the increase in this ratio. Hepatic lipid peroxidiltion was elevated by ischemia/reperfusion, and this elevation was inhibited by free radical scavengers and quina crine. Bile flow and cholate output, but not bilirubin output, were markedly decreased by ischemia/reperfusion and quinacrine restored the secretion. Cytochrome $P_{450}$ content was decreased by ischemia/reperfusion and restored by free radical scavengers and quinacrine to the level of that of the sham operated group. Aminopyrine N-demethylase activity was decreased and aniline p-hydroxylase was increased by ischemia/reperfusion. The changes in the activities of the two enzymes were prevented by free radical scavengers and quinacrine. Our findings suggest that ischemia/reperfusion diminishes hepatic secretory functions as well as microsomal drug metabolizing systems by increasing lipid peroxidation, and in addition to free radicals, other factors such as phospholipase $A_2$ are involved in pathogenes of hepatic dysfunction after ischemia/reperfusion.

• Bulletin of the Korean Chemical Society
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• v.14 no.1
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• pp.107-109
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• 1993

Non-enzymatic glycosylation and fragmentation of collagen molecule were investigated by irradiating Ultraviolet A(UV-A) with or without scavengers of reactive oxygen species (ROS) in the presence of glucose. Non-enzymatic glycosylation was increased by UV-A at high concentration of glucose. It was reduced in the presence of the scavengers of superoxide radical and singlet oxygen, but not reduced in the presence of hydroxy radical scavenger. Fragmentation of collagen was increased by UV-A, but it was decreased in the presence of all ROS scavengers tested. Superoxide radical and singlet oxygen produced by autoxidation of glucose without UV-A may encounter the initial phase of glycosylation. Data presented here suggest that UV-A affects only on the fragmentation process, but all ROS except hydroxy radical act on both processes. It appears that hydroxy radical does not act on the glycosylation process.

• Journal of Applied Biological Chemistry
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• v.43 no.3
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• pp.156-160
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• 2000

The possible mechanism of the DNA strand breaking activity of the hot-water extract of Fructus Chaenomelis (dried fruit of Chaenomeles sinensis) in a closed circular duplex replica form DNA (RFI DNA) was studied through agarose gel electrophresis under various conditions. Induction of DNA strand scission by the hot-water extract of C. sinensis occurred in dose and time-dependent manners. $Cu^{2+}$ was indispensable for the induction of DNA strand breakage. Exogeneous chelating agents inhibited the DNA breaking activity, conforming the catalytic action of $Cu^{2+}$ on generation of free radicals responsible for oxidative damage. Antioxidant enzymes and some radical scavengers were used to investigate the major radical species triggering the DNA strand scission, demonstrating that a highest inhibitory activity was found in the presence of catalase, while less in the presence of tiron (a scavenger for superoxide radical), 2-aminoethyl-isothiuroniumbromide-HBr, cysteamine (scavengers for hydroxyl radical), and 1,4-diazabicyclo [2,2,2] octane (a scavenger for singlet oxygen) in decreasing order. The findings implied that oxygen radical species generated in presence of transition divalent cation during the oxidation of some compounds contained in the hot-water extract of C. sinensis is mainly responsible for inducing genotoxicity.

• The monthly packaging world
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• s.306
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• pp.71-74
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• 2018

• Journal of Photoscience
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• v.9 no.2
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• pp.63-65
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• 2002

This report concerns a putative role of mycosporine-like amino acids (MAA) as natural scavengers of singlet oxygen ($^1$O$_2$) in marine organisms. MAA prepared from the ascidian Lissoclinum patella were found to protect biological systems against detrimental effects of the type II photosensitization in vitro. L. patella MAA were resolved into five components, and the relative $^1$0$_2$ quenching efficiencies were measured for three major components in aqueous media. It turned out that they were all effective in scavenging $^1$0$_2$, to different degrees albeit. The results suggest that physiological relevance of MAA in marine organisms may be found in a 'built-in' defense against photooxidative effects of sunlight.

• Korean Journal of Pharmacognosy
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• v.33 no.1 s.128
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• pp.18-20
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• 2002

Assay-guided fractionation of the methanol extract of the leaves of Albizzia julibrissin has furnished quercitrin (1) and afzelin (2) as the scavengers of DPPH radical. Quercitrin and afzelin showed scavenging activity of DPPH free radical with the $IC_{50}$ values of 17.3 and 71.5 ${\mu}M$, respectively.

• Environmental Analysis Health and Toxicology
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• v.18 no.3
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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.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2000.11a
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• pp.15-21
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• 2000

In chlorine dioxide delignification and bleaching the formation of chlorate is undesirable because it does not react with lignin and is harmful to the environment. Chlorate is mainly formed from the in-situ generated hypochlorus acid which is also the main reason for AOX formation. In previous literature scavengers of hypochlorous acid such as sulfamic aicd, DMSO, and hydrogen peroxide have been added to bleaching stages to reduce AOX formation but less attention has been paid to chlorate reduction. This paper thus focuses on the reduction of chlorate content caused by the following additives, sulfamic acid, DMSO, hydrogen peroxide, and oxalic acid. The results show that only sulfamic acid and DMSO reduce chlorate formation under our chlorine dioxide prebleaching conditions. Results by UV spectroscopy and pH adjustment show that scavengers react with hypochlorous acid much faster than with chlorine. Hydrogen peroxide and oxalic acid react with HClO/$Cl_2$much slower than DMSO and sulfamic acid do. The reason for the ineffectiveness of hydrogen peroxide and oxalic acid is ascribed to their slow reaction rates with HClO compared to that of chlorate formation. The fact that only 30-35% of the chlorate can be reduced by sulfamic acid and DMSO when charged in same mole ratio to chlorine dioxide, suggested that the reaction rate of DMSO and sulfamic acid with hypochlorous aicd are of the same magnitude as that of chlorate formation.

• Journal of Ginseng Research
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• v.13 no.1
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• pp.98-104
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• 1989

In order to determine the specific active oxygen species directly related to chlorophyll bleaching in the leaf-burning disease, we investigated the effects of singlet oxygen (1O2), superoxide radical (O2-), and hydrogen Peroxide (H2O2) on isolated chloroplast suspension and leaf discs from Panax ginseng C.A. Meyer. When the singlet oxygen was added to the chloroplast suspension, the chlorophyll and carotenoid contents were decreased by more than 809), similar to treatment with high light intensity (100 KLux). We assumed that the conversion of dioxygen (O2) produced either in photolysis or in breakdown of hydrogen peroxide to singlet oxygen resulted from photorespiration. On the basis of these experiments , :he inhibitory effects of active oxygen scavengers propylgallic acid (PGA), 2,5-ditetrabutyl hydroquinon (DBH), sodium pyrosulfate (SPS), and ascorbic acid (ABS) were examined. In chloroplast suspension all four scavengers inhibited chlorophyll bleaching by more than 75fl , and in the leaf discs the inhibition rates of SPS, PGA and ABS were 46%, 51%, and 96% respectively.

• Archives of Pharmacal Research
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• v.28 no.5
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• pp.534-540
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• 2005

Activity-guided fractionation of the CH$_2Cl_2$-soluble fraction of the roots of Sophora flavescens furnished five 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scaveng ers: trans-hexadecyl ferulic acid (1) cis-octadecyl ferulic acid (2), trans-hexadecyl sinapic acid (3), (-)-4-hydroxy-3-methoxy-(6aR,11aR)-8, 9-methylenedioxypterocarpan (4) and desmethylanhydroicaritin (8), along with nine known inactive compounds: (-)-maackiain (5), xanthohumol (6), formononetin (7), (2S)-2'-methoxykurarinone (9), (2S)-3${\beta}$,7,4'-trihydroxy-5-methoxy-8-(${\gamma},{\gamma}$- imethylallyl )-flavanone (10), (2S)-7,4'-dihydroxy-5-methoxy-8- (${\gamma},{\gamma}$-dimethylallyl ) -flavanone (11), umbelliferone (12), kuraridin (13), and trifolirhizin (14). Compounds 1-4 and 8 exhibited DPPH free radical scavenging effects at IC$_{50}$ values of 33.01 ${\pm}$ 0.20, 57.06 ${\pm}$ 0.16, 39.84 ${\pm}$ 0.36, 35.83 ${\pm}$ 0.47, and 18.11 ${\pm}$ 0.04${\mu}$M, respectively. L-Ascorbic acid, when used as a positive control, exhibited an IC$_{50}$ value of 7.39 ${\pm}$ 0.01 ${\mu}$M. Compounds 1-4 and 8 also appeared to exert significant scavenging effects on authentic ONOO-, with IC$_{50}$ values of 5.76 ${\pm}$ 1.19, 15.06 ${\pm}$ 1.64, 8.17 ${\pm}$ 4.97, 1.95 ${\pm}$ 0.29 and 4.06 ${\pm}$ 2.41 ${\mu}$M, respectively. Penicillamine (IC$_{50}$= 2.36 ${\pm}$ 0.79${\mu}$M) was used as a positive control. In addition, compounds 2,4,6,8, and 10 were isolated from this plant for the first time.