• Toxicological Research
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• v.17 no.4
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• pp.249-253
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• 2001

Fumonisin B1, a mycotoxin, is thought to induce esophageal cancer in humans and apoptosis in animal cells by inhibiting ceramide synthase. Dumonisin Bl may also generate reactive oxygen species directly or indirectly, leading to DNA damage and lipid peroxidation. In this study, a DNA fragmentation assay, dichlorofluorescein (DCF) analysis, and single cell gel electrophoresis (SCGE) were used to investigate the involvement of cellular free radicals, specifically hydrogen peroxide, in the DNA damaging activity of fumonisin B1. From an in vitro DNA fragmentation assay, E. coli DNA, damage by fumonisin Bl was increased by the addition of superxide dismutase (SOD) and decreased by catalase. SCGE and DCF analysis in vivo showed that the nuclear DNA damage and intracellular free radicals in cultured rat hepatocytes treated with fumonisin B1 were increased with the concentration of fumonisin Bl . DNA damage and free radical generation were inhibited by the addition of catalase. Fumonisin Bl , in the presence of SOD, produces hydrogen peroxide causing oxidative DNA damage and protein malfunction, leading to genotoxicity and cytotoxicity of the toxin.

• The Korean Journal of Food And Nutrition
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• v.29 no.6
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• pp.829-834
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• 2016

Free radicals originate due to the radiolysis of cytoplasmic water with low "Linear Energy Transfer" (LET) radiations. Naringenin (Ng) is a natural antioxidative compound found in citrus fruits. This study revealed that Naringenin (Ng) reduced the radiation damage of critical organs by scavenging oxidative free radicals. In the study, Ng was orally administrated to rats daily for 7 consecutive days, prior to whole body exposure to gamma-rays. The scavenging efficacy was evaluated biochemically by measuring the concentration of cytotoxic byproducts and the activity of enzymes relevant to oxidative free radicals, after extracting the organs from the exposed rat. We observed increased levels of malondialdehyde (MDA) concentration, and decrease in the activities of superoxide dismutase (SOD) and catalase (CAT) in the exposed control group. However, pretreatment with Ng significantly reduced the MDA concentration, and increased the activities of SOD and CAT, as compared to the control group, due to the free radical scavenging by Ng. The results indicate that Ng administration prior to irradiation could protect critical organs from radiation damage.

• Preventive Nutrition and Food Science
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• v.19 no.1
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• pp.34-39
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• 2014

This study evaluated the influence of cooking methods (blanching, pan-frying, and microwaving) on the antioxidant activity of Ligularia fischeri (LF) using myoglobin methods against five different reactive oxygen species (ROS) (i.e., 2,2-diphenyl-1-picrylhydrazyl (DPPH), hypochlorite ions, hydroxyl radicals, peroxyl radicals, and peroxynitrite ions). With respect to DPPH scavenging activity, the antioxidant activities of blanched LF and pan-fried LF were significantly higher (P<0.05) than that of fresh LF for all cooking times. Pan-fried LF and microwaved LF showed higher antioxidant activities against hydroxyl radicals and peroxyl radicals than uncooked LF, while the protective effect of blanched LF was low, except for the at the 3 min cooking time point. Microwaved LF showed high antioxidant activity against all ROS at the 2 min cooking time point. Interestingly, LF that had been microwaved for 2 min and 3 min had high antioxidant values, whereas blanched LF and pan-fried LF had low antioxidant values. The activities of cooked LF against five different ROS were characterized comprehensively by 5-axe cobweb charts.

• Journal of Life Science
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• v.6 no.1
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• pp.48-55
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• 1996

Oxygen free radicals are highly reactive molecules with unpaired electrons, which are produced with in aerobic cells in the course of normal metabolic events. Normally, aerobic cells are protected from the damage of free radicals by antioxidative enzymes such as superoxide dismutase (SOD), catalase, glutathione (GSH) peroxidase, GSH S-transferase and GSH reductase which scabvenge free radicals as well as nonenzymatic antioxidants such as ceruloplasmin, albumin and nontioxidants in order to elucidate antioxidative mechanisms of red ginseng. The treatment with total saponin of red ginseng significantly devreased the contents of malondialdehyde and total free radicals in the liver. On the other hand, total saponin of red ginseng significantly increased the activities of SOD, catalase and GSH reductase and nonprotein-SH level. These results suggest that total saponin of red ginseng exerts an antioxidative effect by increasing endogenous antioxidants.

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.381.2-381.2
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• 2002

There is now increasing evidence that free radicals and active oxygen species are involved in a variety of pathological events. often associated with ageing. Free radical-mediated cell damage and free radical attack on polyunsaturated fatty acids result in the formation of lipid radicals. These lipid radicals react readily with molecular oxygen to produce peroxy radicals responsible for initiating lipid peroxidation. The peroxidation of cellular membrane lipid can lead to cell necrosis and considered to be implicated in a number of pathophysiological conditions as well as in the toxicity of many xenobiotics. (omitted)

• Proceedings of the PSK Conference
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• 2003.04a
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• pp.263.2-263.2
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• 2003

There is now increasing evidence that free radicals and active oxygen species are involved in a variety of pathological events. Free radical-mediated cell damage and free radical attack on polyunsaturated fatty acids result in the formation of lipid radicals. These lipid radicals react readily with molecular oxygen to produce peroxy radicals responsible for initiating lipid peroxidation. The peroxidation of cellular membrane lipid can lead to cell necrosis and considered to ve implicated in a number of pathophysiological conditions including liver disease. (omitted)

• Environmental Analysis Health and Toxicology
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• v.23 no.1
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• pp.41-45
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• 2008

Algal fucoidan is a marine polysaccharide containing sulfur with a wide variety of biological activities including anti-inflammatory and anti-thrombotic effects. Although antioxidants can inhibit inflammatory signals through inhibiting activator protein-1 and/or nuclear factor-kappaB activation, it is obscure whether fucoidan directly scavenges oxy-radicals or indirectly regulates oxidant production and/or antioxidant defense system. The antioxidant activities of fucoidan against peroxyl radicals, peroxynitrites and hydroxyl radicals were determined by the total oxy-radical scavenging capacity (TOSC) assay. The specific TOSC values of fucoidan against peroxyl radicals, peroxynitrites or hydroxyl radicals were $282{\pm}60$, $43{\pm}1$ or $40{\pm}1\;TOSC/mg/mL$, respectively. These specific TOSC values against peroxyl radicals, peroxynitrites or hydroxyl radicals are 23, 12, or 13% of the specific TOSC values of glutathione, a positive control, respectively. These results suggest that fucoidan has direct oxy-radical scavenging capacity, which may be related with anti-inflammatory effect of fucoidan.

• Toxicological Research
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• v.23 no.3
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• pp.263-269
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• 2007

Although taurine (2-aminoethanesulfonic acid) can inhibit oxidative stress in both animal and epidemiological studies, it is obscure whether taurine directly scavenges oxy-radicals or indirectly regulates oxidant production and/or antioxidant defense system. The reason for this discrepancy remains unknown but may be due, in part, to the lack of a validated assay system for evaluating oxy-radical scavenging capacity. The antioxidant activities of taurine and hypotaurine (2-aminoethanesulfinic acid), a precursor of taurine, against peroxyl radicals, hydroxyl radicals and peroxynitrites were determined by the total oxy-radical scavenging capacity (TOSC) assay and cell-based assay using H4IIE cells. tert-Butylhydroperoxide or hydrogen peroxide-induced cell toxicity determined by MTT assay was markedly inhibited by 10mM taurine or hypotaurine. The tert-butylhydroperoxide- or hydrogen peroxide-induced changes in oxidative stress markers, such as cellular glutathione and malondialdehyde, were ameliorated by 10mM taurine or hypotaurine. However, specific TOSC values calculated from the slope of the linear regression for taurine against peroxyl radicals, hydroxyl radicals or peroxynitrites were all less than 1 TOSC/mM. On the other hand specific TOSC values for hypotaurine against peroxyl radicals, hydroxyl radicals or peroxynitrites were 48, 2096, or 69 TOSC/mM, respectively. These results suggest that taurine protects cells against oxidative insults, which is not ascribed to directly scavenging activity of taurine against oxy-radicals. These results support the idea that the oxidation state of sulfur in antioxidants may be a determinant of oxy-radical scavenging capacity.

• Communications of the Korean Mathematical Society
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• v.8 no.2
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• pp.213-223
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• 1993

• Preventive Nutrition and Food Science
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• v.22 no.3
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• pp.223-230
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• 2017

The purposes of this study were to produce polysaccharides from red pepper stems using different extraction methods and evaluate their chemical composition, in vitro biological capacities, and rheological properties. Two polysaccharides were extracted from red pepper stems using an autoclave and alkali treatments, and the extracts were named PAU and PAL, respectively. The contents of total phenolics and flavonoids were significantly higher in PAU than those in PAL. PAU exhibited greater scavenging activities on 2,2-diphenyl-1-picrylhydrazyl radicals, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt radicals, superoxide radicals, and nitrite compared to PAL, suggesting that PAU served as better antioxidants. Similarly, in vitro inhibitory abilities against carbohydrate hydrolyzing enzymes of PAU were higher than those of PAL. Steady shear rheological analysis demonstrated that PAU showed higher psuedoplastic shear-thinning behavior compared to PAL. Based on the results from dynamic shear rheological properties, it was found that both samples had predominantly viscous behavior rather than elastic behavior.