• Korean Journal of Food Science and Technology
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• v.34 no.3
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• pp.396-399
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• 2002

Electron spin resonance (ESR) spectroscopy was used to investigate the effect of irradiation dose and storage time on the free radical concentrations in gamma-irradiated sesame (Korean and Sudan) and perilla seeds (Korea). The samples were sealed with packed pyrex tube (50 g respectively) and then irradiated with doses of 0, 1, 5 and 10 kGy at room temperature using a Co-60 irradiator. Each sample in ESR quartz tube were calculated with ESR signals by Bruker-EPR spectrometer for 4 weeks. Free radicals detected for irradiated and unirradiated samples were higher than those of unirradiated ones. Since the free radical concentrations linearly incresed with the applied doses $(1{\sim}10\;kGy)$, highly positive correlation coefficients $(R^2=0.9926{\sim}0.9994)$ were obtained between irradiation doses and free radical concentrations right after irradiation. Although the free radical concentrations decreased with storage time, the signals of free radical in irradiated samples were observed even after 4 weeks of storage at room temperature.

• Preventive Nutrition and Food Science
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• v.14 no.4
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• pp.277-282
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• 2009

The antioxidant potency of methanolic extract of Duchesnea indica (MDI; Indian strawberry) was investigated by employing various established in vitro systems, such as total phenolic content, 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity, reducing power assay, metal chelating assay, superoxide radical scavenging activity and protective ability of DNA damage and protein oxidation. MDI inhibited metal chelating by 75.57% at 2 mg/mL, scavenged 50% DPPH free radical at 29.13 ${\mu}$g/mL, and eliminated approximately 46.21% superoxide radical at the concentration of 1 mg/mL. In addition, MDI showed strong ability on reducing power, DNA damage protection and protein oxidation protection. Overall, results suggested that MDI might be beneficial as a potent antioxidant and effectively employed as an ingredient in food applications.

• Preventive Nutrition and Food Science
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• v.15 no.1
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• pp.44-50
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• 2010

Hawthorn fruit is a conventional medicine used in treating cardiovascular diseases. Its therapeutic effects may relate to its antioxidant compounds. In this study, we evaluated the antioxidant activity of $CH_2Cl_2$, EtOAc, n-butanol and water fractions from 70% methanolic hawthorn fruit extract by total phenolic and flavonoid contents, total antioxidant activity, DPPH free radical scavenging activity, superoxide radical scavenging activity, reducing power assay, lipid peroxidation inhibitory activity and protective effect against hydroxyl-radical-induced DNA damage. Results showed that the EtOAc fraction contained significantly greater antioxidant activities than other fractions, which suggests that the potent EtOAc fraction should be used for further studies to identify the antioxidant compounds.

• YAKHAK HOEJI
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• v.44 no.6
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• pp.613-619
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• 2000

The author examined whether the methanol extracts of Opuntia ficus-indica fruit and Saururus chinensis have the inhibitory action on xanthine/xanthine oxidase (X/XO)-, $FeCl_2/ascorbic$ acid- and arachidonic acid-induced neurotoxicity in mouse cortical cell cultures. The methanol extracts ($10\;{\mu}g/ml{\sim}1\;mg/ml$) of Opuntia ficus-indica and Saururus chinensis were exhibited 53-89% and $48{\sim}100%$ inhibitory action on X/XO-induced neurotoxicity, respectively. At the range of same concentration, both extracts also attenuated the $FeCl_2/ascorbic$ acid-induced neurotoxicity by $35{\sim}100%$ and $15{\sim}98%$, respectively. In arachidonic acid neurotoxicity, the methanol extract (1 mg/ml) of Opuntia ficus-indica and Saururus chinensis reduced neuronal injury by 22% and 38%, respectively. These results suggest that Opuntia ficus-indica fruit and Saururus chinensis may contribute the neuroprotection in certain free radical-mediated neuronal injury.

• YAKHAK HOEJI
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• v.45 no.1
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• pp.101-107
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• 2001

Green tea catechins (GTC) and its major component, (-)-epigallocatechin gallate (EGCG) were studied for their protective effects against reactive oxygen species (ROS)-induced oxidative stress. GTC and EGCG skewed the strong antioxidative effects on the lipid peroxidation of ethyl linolate with Fenton's reagent and free radical scavenging effect to DPPH radical generation. They also protected $H_2O$$_2$- or KO$_2$-induced cytotoxicity in CHL cells or mouse splenocytes. These results indicate that GTC and EGCG are capable of protecting the lipid peroxidation, flee radical generation and cytotoxicity induced by ROS. The mechanism of inhibition in ROS-induced cytotoxicity may be due to their antiofidative and free radical scavenging properties. Therefore, GTC and EGCG may be useful chemopreventive agents by protecting the free radical generation which are involved in cancer and aging.

• Bulletin of Food Technology
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• v.10 no.3
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• pp.4-27
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• 1997

동맥경화증과 암은 현대인의 주요한 사망원인들이다. 동맥경화증과 암이 free radical과 관련이 깊다는 보고가 점차 축적되고 있다. 동맥경화증과 암의 발생과 예방, 그리고 지금까지의 연구상황에 대하여 소개하고자 한다.

• Proceedings of the Korean Society of Life Science Conference
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• 2001.09a
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• pp.94-94
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• 2001

• Bulletin of the Korean Chemical Society
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• v.22 no.1
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• pp.110-112
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• 2001

• Toxicological Research
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• v.11 no.1
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• pp.57-62
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• 1995

To investigate the ultrastructural changes of kidney and clarify to a cause of its changes in lead intoxicated rats, the 0.5% lead acetate administed orally to the rats and those were sacrifled at 2 day, 1, 2, 4, 6 and 8 week after the treatment of lead acetate. Each extirpated kidney was histopathologically examined under the electron microscopy and histochemical examination was also carried out. Concomitantly, the activity of free radical metabolizing enzyme was determined. The blood levels of lead concentration showed a gradual increase from the first group reaching the plateau at the one or two week group with the slightly decreasing value throughout the whole course of the experiment. And the urinary ALA concentration showed a gradual increase from the first group to the 8 week group. In the kidney tissue of rat sacrified at 6 week, the proximal tubular cells showed dilatation of endoplasmic reticulum, mitochondrial swelling, increased numbers of secondary lysosomes and myelin figure-like residual bodies on electron microscope and oxygen free radicals are identified by histochemistry on light microscope whereas there were no differences in the activity of catalase and glutathione peroxidase between the lead acetate treated group and control group. But the activity of xanthine oxidase was more increased in lead acetate treated rats than control group. Furthermore, the superoxide dismutase activity was significantly increased in the experimental group than the control group. In conclusion, it is assumed the kidney damage in lead intoxicated rat may be induced by free radicals.

• Journal of Ginseng Research
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• v.36 no.3
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• pp.256-262
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• 2012

Reactive oxygen species play critical role in kidney damage. Free radical-scavenging activities of Panax ginseng are known to be increased by heat-processing. The structural change of ginsenoside and the generation of Maillard reaction products (MRPs) are closely related to the increased free radical-scavenging activities. In the present study, we have demonstrated the Maillard reaction model experiment using ginsenoside Re and glycine mixture to identify the renoprotective effect of MRPs from ginseng or ginsenosides. Ginsenoside Re was transformed into less-polar ginsenosides, namely Rg2, Rg6 and F4 by heat-processing. The free radical-scavenging activity of ginsenoside Re-glycine mixture was increased in a temperature-dependant manner by heatprocessing. The improved free radical-scavenging activity by heat-processing was mediated by the generation of antioxidant MRPs which led to the protection of LLC-PK1 renal epithelial cells from oxidative stress. Although the free radical scavenging activities of less-polar ginsenosides were weak, they could protect LLC-PK1 cells from oxidative stress. Therefore, MRPs and less-polar ginsenosides contributed to the combined renoprotective effects against oxidative renal damage.