• Journal of Life Science
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• v.12 no.2
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• pp.75-79
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• 2002

Tea catechins, the most important compounds in tea polyphenols, can efficiently scavenge superoxide anion free-radical ($O_2$.), hydroxyl radical. (.OH) The mechanism of scavenging active oxygen free radicals was investigated by ESR spin trapping technique and Chemiluminescence. Results showed that various tea catechins constitute an antioxidant cycle in accordance with the decreasing order of the first reductive potential, and produce the effect of cooperative strength each other. Esterificated catechins could scavenge active oxygen free radicals more effectively than the non-esterificated ones. When.OH and $O_2$.- were scavenged by (-)-epigallocatechin gallate [(-)- EGCG], the stoichiometric factors were 6, and the rate constants of scavenging reaction reached $7.71{\times}10^6$ and $3.52{\times}10^{11}$ L $mmol^{-1}s^{-1}$, respectively. In the mean time, tea catechins could scavenge superoxide anion fiee radical ($O_2$-.) and hydroxyl radical (.OH) in a dose dependent manner. But at higher concentration or pH value, tea catechins can induce the prooxidant.

• Biomolecules & Therapeutics
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• v.7 no.2
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• pp.121-126
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• 1999

In an attempt to define the effects of hyperbaric oxygen treatment on the lipid peroxidation and oxygen free radical reactions in rats exposed to carbon monoxide, we studied malondialdehyde (MDA) level and activities of catalase and superoxide dismutase in the kidney of the rats exposed to carbon monoxide. Male Sprague-Dawley albino rats weighing 240 to 260 gm were used. Experimental groups consist of Control group (=breathing with air), HBO group (=exposed to hyperbaric oxygen 〔HBO, 3ATA, 100%〕 after air breath), CO group (=exposed to CO〔3,970 ppm〕after air breath), CO-Air group (=exposed to CO after air breath followed by air breath) and CO-HBO group (=exposed to CO after air breath followed HBO treatment). The CO group showed significantly higher MDA level, catalase activity and SOD activity as compared to that of control group. The CO-HBO group showed significantly lower MDA level as compared to that of CO group, and did not show significantly lower catalase activity and SOD activity as compared to that of CO group. These results suggest that the excessive oxygen free radicals is an important determinant in pathogenesis of CO-induced nephrotoxicity and HBO inhibits the lipid peroxidation caused by excessive oxygen free radicals in the kidney of the rats exposed to carbon monoxide.

• Preventive Nutrition and Food Science
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• v.10 no.4
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• pp.326-332
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• 2005

A methanol extract of mulberry cake prepared from mulberry fruits (Morus spp.) was shown to have strong scavenging activities against DPPH, superoxide and hydroxyl radicals. Eleven phenolic compounds were isolated from the mulberry cake by a combination of Diaion HP-20, silica gel (or polyamide), Sephadex LH-20 column chromatographies, preparative HPLC and TLC. Their chemical structures were characterized as procatechuic acid (PCA), caffeic acid (CA), cyanidin 3-O-$\beta$-D-glucopyranoside (CyG) and cyanidin $3-O-\beta­D-rutinoside$ (CyR), rutin (RT), isoquercitrin (IQT), astragalin (AG), quercetin (QT), morin (MR), di-hydroquercetin (DHQ), and 4-prenylmoracin (PM) by spectral analysis and the published data. Most of the phenolic constituents were effective scavengers of DPPH, superoxide and hydroxyl radicals, and especially caffeic acid and 4-prenylmoracin showed potent superoxide and hydroxyl radical scavenging activity, in which their activities were higher than that of the well-known antioxidant, BHT (p< 0.05). Dehydroquercetin and quercetin also exhibited strong superoxide and hydroxyl radical scavenging activities. These results suggest that mulberry cake containing antioxidant phenolic compounds may be useful as natural antioxidants in functional foods and cosmetics.

• Bulletin of the Korean Chemical Society
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• v.7 no.6
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• pp.478-479
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• 1986

• Journal of Acupuncture Research
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• v.15 no.2
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• pp.135-145
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• 1998

Bupleury radix has been used for the treatment of fever, liver disease, inflammation in traditional medicine. The present study was carried out to evaluate the antioxidant effects of Bupleury radix aqua-acupuncture solution (BRAS) in vitro. Oxygen derived free radicals produced in the course of normal aerobic life, such as superoxide anion radical($O_2^-$ ), hydroxyl radicaI( OH), hydrogen peroxide($H_2O_2$) and singlet oxygen($^1O_2$) can attack polyunsaturated fatty acid in cell membranes, enzymes, other cell compounds, and give rise to lipid peroxidation, DNA damage, lipofuscin accumulation, structure alteration of cell membrane and cell death. In this study, antioxidant effects of BRAS on lipid peroxidation were determined according to the method of TBA. BRAS inhibited markedly peroxidation of linoleic acid during the autoxidation, and also inhibited lipid peroxidation induced by hydroxyl radical derived from $H_2O_2-Fe^{2+}$ in rat liver homogenate. And BRAS showed 30% scavenging effect on DPPH radical, also exhibited a 30% inhibitory effect on superoxide generation from xanthine-xanthine oxidase system. In addition, BRAS protected the cell death induced by tert-butyl hydroperoxide(t-BHP) and significantly increased cell viability in the normal rat liver cell(Ac2F).

• Biomolecules & Therapeutics
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• v.10 no.1
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• pp.25-31
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• 2002

This study was carried out to identify the effect of oxidative stress on the pathogenesis of manganese intoxication. Five rats in experimental group were given with $MnCl_2$intraperitoneally for 4 weeks(4 mg/kg once daily 5 days per week) and another five rats for control group were given with normal saline. In experimental group, manganese concentrations increased significantly in nucleus accumbens by 142% (p<0.05), SOD activities increased significantly by 124%(p<0.01), and MDA concentrations increased significantly 148%(p<0.05) compared with control group. Among fatty acids, total n-6 polyunsaturated fatty acids(PU) increased significantly by 231%(p<0.05) compared with control group. Arachidonic acids(AA) increased by 224%(p<0.05), and these increase were composed mostly of n-6 polyunsaturated fatty acids(PUFA). Among n-3 PUFAs except linolenic acids, eicosapentanolc acid(EPA) decreased significantly by 38%(p 0.01) and docosahexanoic acids(DHA) decreased by 30% p<0.05) compared with control group. Our results suggest that the oxygen free radicals produced by manganese may cause compositional changes of fBtty acids in nucleus accumbens of the rat. Characteristics of fatty acids compositional changes by manganese were the decrease of EPAs and DHAs(n-3 PUFAs), and increase of AAs(n-6 PUFAs). These changes with the increase of MDA, suggest that manganese neurotokxcity is caused by lipid perokidation mediated with oxygen free radicals, especially superoxide radicals.

• Korean Journal of Pharmacognosy
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• v.34 no.4 s.135
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• pp.324-326
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• 2003

The methanol (MeOH) extract and ist fractions of Taraxacum mongolicum (Compositae) were examined for their scavenging effects on 1,1-diphenyl-2- phenylhydrazyl (DPPH) and superoxide radicals, and hepatoprotective effects on tacrine-induced cytotoxicity in human hepatoma cell line, Hep G2 cells. Both methylene chloride $(CH_2Cl_2)$ and butanol (n-BuOH) soluble fractions of the MeOH extract showed the free radicals scavenging and hepatoprotective effects. From these results, it is suggested that hepatoprotective effect of these fractions partly relies on their free radical scavenging activity.

• Journal of Sericultural and Entomological Science
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• v.42 no.2
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• pp.93-98
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• 2000

This study was designed to investigate the effect of silkworm powder on oxygen radicals and their scavenger enzymes in brain membrances of SD rats. Hydroxyl radical (OH) levels resulted in a considerable decreases in brain mitochondria fraction. Superoxide radical (O$_2$) levels were a slightly decreased in brain cytosol fraction. Lipid peroxide (LPO) and Oxidized protein (OP) levels were significantly decreased in brain mitochondria and microsomes fraction. Mn-superoxide dismutase (SOD) activity was remarkably increased in the mitochondria fraction. Cu and Zn-SOD activities were effectively increased in brain cytosol fraction. GSHPx activity was considerably increased in brain cytosol fraction. These results suggest that anti-aging effect of silkworm plays an effective role in attenuating an oxidative stress and increasing a scravenger enzyme activity in brain membranes.

• Korean Journal of Plant Resources
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• v.23 no.3
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• pp.207-213
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• 2010

Hovenia dulcis Thunb fruits were successively extracted with hot water, water, methanol, ethyl acetate, and chloroform. The crude extracts were investigated for potential antioxidant by measuring scavenging against DPPH free radicals, reducing power, superoxide radicals, and protection of protein damage and cultured cells from a lethal dose of hydrogen peroxide ($H_2O_2$). In all chemical assays used, the hot water extract of H. dulcis fruits, which contained $61.14{\pm}2.57$ (Tannic acid mg/g extract, n=3) of total phenolic compounds contents exhibited highest activity in in vitro models of DPPH free radical scavenging activity, reducing power assay, superoxide radical scavenging activity and protection of protein damage. In addition, the hot water extract protected cultured RAW 264.7 macrophages from a lethal dose of $H_2O_2$ and reduced reactive oxygen species level in RAW 264.7 cells.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.7
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• pp.3065-3071
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• 2012

Aim: The present investigation was to evaluate the effects of essential oils of Wedelia chinensis (Osbeck) on free radicals and in vivo antioxidant properties. Methods: Essential oils were extracted using hydro-distillation and compound analysis was performed by GC-MS analysis. Screening for inhibitory activity was conducted by DPPH and OH-scavenging assays. In addition an in vivo study was carried out in cell line implanted cancer bearing mice with assessment of levels of catalase, superoxide dismutase, glutathione peroxidase, lipid peroxidation, nitric oxide and reduced glutathione. Finally, lungs were dissected out for histopathology study of metastasis. Results: GC-MS analysis revealed the presence of carvocrol and trans-caryophyllene as the major compounds with 96% comparison with the Wilily and NBS libraries. The essential oil exhibited significant inhibition in DPPH free radical formation. Whereas reducing power and hydroxyl radical scavenging activity are dose dependent. When compared with the standard, it was found that the essential oil has more or less equal activity in scavenging free radicals produced. In the animal studies, the level of antioxidant enzymes catalase, superoxide dismutase and glutathione peroxidase, as well as glutathione, were found to be increased in treated groups whereas lipid peroxidation and nitric oxide were reduced. Histopathology report also shows that the essential oil has a significant combating effect against cancer development. Conclusion: In all the in vitro assays, a significant correlation existed between the concentrations of the essential oil and percentage inhibition of free radicals. The in vivo studies also has shown a very good antioxidant property for the essential oil during cancer development. From, these results the essential oil can be recommended for treating disease related to free radicals and to prevent cancer development.