• Journal of Physiology & Pathology in Korean Medicine
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• v.19 no.6
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• pp.1615-1621
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• 2005

Reactive oxygen species (ROS) and reactive nitrogen species (RNS) are widely implicated in the aging process and age-related diseases. The present study was carried out to investigate scavenging activities of Junglans sinensis extract and its subfraction using fluorescent probes, DCF-DA, DAF-2 and DHR 123. Jungians sinensis was washed and crushed. The crushed Junglans sinensis was extracted 3times, each time with 3 volumes of methyl alcohol at $60^{\circ}C$ for 24 h. The extract was filtered and evaporated under a reduced pressure using a rotary evaporator to yield 16 g. Scavenging activities of $ONOO^-$ was measured by Kooy' method and ROS was measured by DCFDA assay. Junglans sinensis had the marked scavenging activites of $ONOO^-$, NO and $O_2^-$. Junglans sinensis scavenged $ONOO^-$ through electron donation and dose-dependently inhibited the nitration of bovine serum albumin by $ONOO^-$. Junglans sinensis also had ROS scavenging activity. Especially, ethylacetate fraction of Junglans sinensis showed the most effective scavenging activities for ROS and RNS. These results suggest that Junglans sinensis might be developed as an effective ROS and RNS scavenger Therefore, Junglans sinensis might be used as a preventive agent for the aging and relevant to aging of illness.

• 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.

• Journal of Applied Biological Chemistry
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• v.54 no.3
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• pp.184-189
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• 2011

Polysaccharide (PS) was fractionated from hot-water extract of Artemisia iwayomogi Kitamura stems. PS showed considerably higher hydroxyl radical scavenging activity than caffeic acid and glutathione. PS showed lower superoxide anion radical scavenging activity than hydroquinone and ascorbic acid. The scavenging activity of PS on the reactive oxygen species (ROS) induced by human neutrophils with zymosan was determined by the lucigenin-enhanced chemiluminescence assay. The scavenging effect of the PS on ROS as determined by the chemiluminescence assay was about 2-fold stronger than that of ascorbic acid at the same concentration. PS significantly decreased protein carbonyl and malonaldehyde contents in UVB irradiated skin homogenates, which was comparable to glutathione at the same concentration. This result suggested that PS derived from A. iwayomogi Kitamura stems may be a potent candidate as functional compound for the protection on UVB induced skin damage in cosmetics.

• Food Science and Biotechnology
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• v.18 no.6
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• pp.1523-1527
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• 2009

The present study was to investigate the in vitro antioxidant potential of hot water extract and its fractions from dichloromethane ($CH_2Cl_2$), ethyl acetate (EtOAc), n-butanol (n-BuOH), and water ($H_2O$) of castor-aralia (Kalopanax pictus) leaves using different antioxidant tests. Among these crude extract and fractions, EtOAc fraction exhibited higher antioxidant potency than others in 1,1-diphenyl-2-pricylhydrazyl (DPPH) free radical scavenging, reducing power assay, and reactive oxygen species (ROS) scavenging activity. However, $CH_2Cl_2$ fraction showed higher hydroxyl radical scavenging and DNA damage protective activity. This work demonstrates the potential of castor-aralia leaves as antioxidant functional food ingredients.

• 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.

• Journal of the Korean Applied Science and Technology
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• v.41 no.2
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• pp.447-458
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• 2024

In this study, the antioxidizing effect of 2,3-dicaffeoyl-epi-quinic acid (DEQA) was investigated. The antioxidant activity was evaluated by measuring the scavenging effect on DPPH radical and peroxynitrite and the reducing power on ferric ion. DEQA showed a scavenging effect and reducing power comparable to vitamin C used as a positive control. Also, DEQA effectively inhibited production of intracellular reactive oxygen species (ROS) in HT-1080 cells, showing the scavenging ratio of 43.8% even at 10 µM concentration of DEQA after 2 hours in HT-1080 treated with H₂O₂. In addition to this, DEQA inhibited the production of nitric oxide (NO) very effectively in Raw 264.7 cells. The above results suggest that DEQA has the potential to be developed as a natural antioxidant.

• Proceedings of the Microbiological Society of Korea Conference
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• 2001.11a
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• pp.61-73
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• 2001

• The Korea Journal of Herbology
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• v.22 no.1
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• pp.53-61
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• 2007

Objectives: Our previous studies have clearly demonstrated that the scavenging activity of reactive oxygen species (ROS), protective effect of lipid peroxidation (LPO), and inhibition of cytochrome P450 isozymes (CYPs) from the Circium japonicum aqua-acupuncture solution (CJAS). But, Circium japonicum water extracted solution (CJWS) was weakly reported in cardiovascular diseases such as oxidative stress-mediated atherosclerosis or its value evaluated. Methods: CJWS was assessed to determine the mechanism of its scavenging activity of ROS and inhibitory effect of CYP 2E1. Results: CJWS exhibited a concentration-dependent scavenger of DPPH and superoxide anions radicals using different assay systems. In addition, CJWS showed dose-dependent free radical scavenging activity, including hydroxyl radicals, peroxynitrite, and nitric oxide. The CJWS was also found to be effective in protecting rat liver homogenate against LPO. Futhermore, the CJWS showed significant inhibition of CYP 2E1 induced by pyrazol in a rat liver microsome. Conclusion : ROS and CYPs may play a role in several diseases, such as cardiovascular disease and heart failure. Our study demonstrated that the CJWS has excellent scavenging activity of ROS. Hence, it is worthwhile to investigate the potential effectiveness of CJWS in preventing oxidative stress-mediated cardiovascular diseases.

• Bulletin of the Korean Chemical Society
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• v.22 no.4
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• pp.362-366
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• 2001

To show the effects of metallothionein (MT) on the activity of enzymes involved in the removal of reactive oxygen species, MT has been added to the assay systems of superoxide dismutase (SOD), catalase and peroxidase. We have used assay systems of SOD based on NADPH oxidation and nitrite formation from hydroxylammonium chloride as an assay of superoxide breakdown rate. The two assay systems showed different results at the high concentration of MT. MT showed the scavenging of superoxide in the SOD assay system in the presence and absence of SOD. MT added to the SOD assay system behaved as an activator of SOD, but apo-MT behaved as an inhibitor. When MT was added to the assay system in the presence of a fixed amount of SOD, the breakdown rate of superoxide increased. The effects of MT on the decomposition of hydrogen peroxide and the activity of catalase and peroxidase decomposing hydrogen peroxide were evaluated. MT decreased the activities of catalase and peroxidase. We have concluded that the function of MT as an antioxidant might effect the level of superoxide scavenging and not the level of hydrogen peroxide.

• Molecules and Cells
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• v.37 no.7
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• pp.532-539
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• 2014

We isolated a rice (Oryza sativa L.) WRKY gene which is highly upregulated in senescent leaves, denoted OsWRKY42. Analysis of OsWRKY42-GFP expression and its effects on transcriptional activation in maize protoplasts suggested that the OsWRKY42 protein functions as a nuclear transcriptional repressor. OsWRKY42-overexpressing (OsWR KY42OX) transgenic rice plants exhibited an early leaf senescence phenotype with accumulation of the reactive oxygen species (ROS) hydrogen peroxide and a reduced chlorophyll content. Expression analysis of ROS producing and scavenging genes revealed that the metallothionein genes clustered on chromosome 12, especially OsMT1d, were strongly repressed in OsWRKY42OX plants. An OsMT1d promoter:LUC construct was found to be repressed by OsWRKY42 overexpression in rice protoplasts. Finally, chromatin immunoprecipitation analysis demonstrated that OsWRKY42 binds to the W-box of the OsMT1d promoter. Our results thus suggest that OsWRKY42 represses OsMT1d-mediated ROS scavenging and thereby promotes leaf senescence in rice.