• 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 Life Science
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• v.33 no.10
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• pp.776-782
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• 2023

Silymarin, which is derived from dried Silybum marianum (milk thistle) seeds and fruits, possesses various beneficial properties, such as hepatoprotective, antioxidative, anti-inflammatory, and anticancer activity. This research aimed to explore the antioxidative activity of silymarin against oxidative stress and understand its molecular mechanism in RAW 264.7 cells. The study employed cell viability and reactive oxygen species (ROS) formation assays and western blot analysis. The results demonstrated that silymarin effectively reduced intracellular ROS levels induced by lipopolysaccharide (LPS) in a dose-dependent manner without causing any cytotoxic effects. Moreover, silymarin treatment significantly upregulated the expression of heme oxygenase (HO)-1, a phase II enzyme known for its potent antioxidative activity. Additionally, silymarin treatment significantly induced the expression of nuclear factor-erythroid 2 p45-related factor (Nrf) 2, a transcription factor responsible for regulating antioxidative enzymes, which was consistent with the upregulated HO-1 expression. To investigate the involvement of key signaling pathways in maintaining cellular redox homeostasis against oxidative stress, the phosphorylation status of mitogen-activated protein kinase (MAPK) and phosphoinositide 3-kinase (PI3K) was estimated by western blot analysis. The results showed that silymarin potently induced HO-1 expression, which was mediated by the phosphorylation of p38 MAPK. To further validate the antioxidative potential of silymarin-induced HO-1 expression, tert-butyl hydroperoxide (t-BHP)-induced oxidative damage was employed and attenuated by silymarin treatment, as identified by a selective inhibitor for each signaling molecule. In conclusion, silymarin robustly enhanced antioxidative activity by inducing HO-1 via the Nrf2/p38 MAPK signaling pathway in RAW 264.7 cells.

• Korean Journal of Agricultural Science
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• v.43 no.2
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• pp.186-193
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• 2016

This study focused on the evaluation of the antioxidative effects of lotus seeds from golden colored flowers. The lotus seeds were extracted with ethanol and then fractionated into 4 fractions, ethyl acetate (EtOAc), n-butanol, methylene chloride, and n-hexane. The comparison of antioxidative activities of the extract and fractions from the lotus seeds was carried out using an in vitro radical scavenging model and the total phenol content was analyzed. Of the tested extracts and fractions, the EtOAc fraction of the lotus seeds showed the strongest 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity with 96.24% at a concentration of $100{\mu}g/mL$. In addition, the hydroxyl radical scavenging activity of the lotus seed EtOAc fraction was also increased in a concentration dependent manner with the concentrations tested ranging from 5 to $100{\mu}g/mL$. Moreover, the EtOAc fraction showed the highest scavenging activity for nitric oxide and superoxide anion radicals. In particular, of all the extracts and fractions, the EtOAc fraction showed highest contents of total phenols. These results indicate that lotus seeds have potential as an antioxidative agent against oxidative stress involving reactive oxygen species. Furthermore, the EtOAc fraction of lotus seeds includes promising oxidative stress-protective compounds.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.52 no.3
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• pp.264-273
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• 2007

In order to examine the cross-tolerance of two chilling-tolerant cultivars (Donganbyeo and Heukhyangbyeo) and two chilling-susceptible cultivars (Hyangmibyeo and Taekbaekbyeo) to salt, paraquat, and drought, changes of physiological response and antioxidant enzymes were investigated. The seedlings were grown in a growth chamber until the 4-leaf stage. The seedlings were exposed to chilling at $5^{\circ}C$ for 3 days. For drought treatment, the seedlings were subjected to drought by withholding water from plants for 5 days. For paraquat study, plants were sprayed with $300{\mu}M$ paraquat. For the salt stress, the seedlings were transferred to the Hoagland's nutrient solution containing 0.6% (w/v) NaCl for 4 days. Chilling-tolerant cultivars showed cross-tolerant to other stresses, salt, paraquat, and drought in physiological parameters, such as leaf injury, chlorophyll a fluorescence, and lipid peroxidation. The baseline levels of antioxidative enzyme activities, catalase (CAT) and peroxidase (POX) activities in chilling-tolerant cultivars were higher than in the chilling-susceptible cultivars. However, there were no differences in ascorbate peroxidase (APX) and glutathione reductase (GR) activities between chilling-tolerant and -susceptible cultivars in untreated control. CAT activity in chilling-tolerant cultivars was higher than that in chilling-susceptible cultivars during chilling, salt, and drought treatments, but not during paraquat treatment. However, other antioxidative enzymes, APX, POX, and GR activities showed no significant differences between chilling-tolerant and -susceptible cultivars during chilling, salt, paraquat, and drought treatments. Thus, it was assumed that CAT contribute to cross-tolerance mechanism of chilling, salt, and drought in rice plants.

• Journal of the Korean Society of Food Culture
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• v.20 no.6
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• pp.721-730
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• 2005

Recently, epidemiological evidence has raised concerns that moderate elevation in body iron stores may increase oxidative stress and the risk of cardiovascular disease and cancer. Onion flesh or peel contains antioxidant such as flavonoids and alk(en)ylcysteine sulphoxides. This study was conducted to examine the effect of onion flesh or peel feeding on antioxidative capacity in aged rats supplemented with high dietary iron. Thirty-two Sprague-Dawley male 16-month-old rats weighing $618{\pm}6g$ were acclimated for 10 days with medium-iron diet (35ppm in diet), and blocked into 4 groups according to their body weights and raised for 3 months on either control diets (adequate iron-35ppm or high iron-350ppm) or experimental diets containing onion flesh/peel (5% w/w in diet) with high iron (350ppm). Rats fed high iron-onion peel diet had significantly high quercetin and isorhamnetin levels in plasma whereas rats fed high iron-onion flesh diet did not show. Plasma TBARS level was lowered by onion flesh or peel diet with high iron supplementation. However, there was no significant difference in cellular DNA damage in brain and kidney tissue among all experimental groups. We concluded that high iron diet (10 times higher than requirement) tend to increase oxidative stress and it is plausible that onion flesh or peel feeding enhances antioxidative capacity in the elderly even with iron supplementation.

• Korean Journal of Plant Resources
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• v.10 no.3
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• pp.227-230
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• 1997

The authors isolated four olefinic catechols, commonly referred to as urushiol, from the sap of Korean lacquer tree(Rhus vernicifera STOKES) with stronger antioxidative activities than $\alpha-tocopherol$. The hexane extract with a free radical scavenging activity was purified by silica and ODS gel column chromatography. The active compounds were identified by MS and $^1H-NMR$ as 3-[8'(Z),11'(Z),14'-pentadecatrienyl]catechol, 3-[8'(Z),11'(Z)-pentadecadienyl]catechol, 3-[8'(Z)-pentadecenyl] catechol, and 3-pentadecylcatechol. All of these compounds showed strong free radical scavenging activities on 1,1-diphenyl-2-picrylhydrazyl(DPPH) radical, in which 3-pentadecylacatechol exhibited the highest activity ($IC_{50}$: $1.2{\mu}g/ml$). They also showed a significant inhibitory activity on lipid peroxidation ($IC_{50}$: 2.1 - 3.5 ${\mu}g/ml$). The antioxidative activity of 3-pentadecylcatechol on DPPH radical and lipid peroxidation is approximately two times greater than that of $\alpha$-tocopherol. The results suggest that the urushiol derivatices may contribute to the preservative characteristics effective against oxidative stress and could be a good source for industrial applications including a coating material.

• Korean Journal of Clinical Laboratory Science
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• v.48 no.1
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• pp.1-7
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• 2016

The aim of this study was to evaluate the cytotoxicity of cadmium chloride ($CdCl_2$), toxicant, and the protective effect of Chelidonium majus (CM) extract on $CdCl_2$-induced cytotoxicity in cultured NIH3T3 fibroblasts. Cell viability, the effect of butylated hydroxytoluene (BHT) against $CdCl_2$, and the antioxidative effects including DPPH-free radical scavenging activity, superoxide anion-radical scavenging activity (SSA), and lactate dehydrogenase (LDH) activity were assessed. $CdCl_2$ caused a significant dose-dependent decrease in cell viability, and $XTT_{50}$ value was determined at 38.7uM of $CdCl_2$. It was determined as highly-toxic by Borenfreund and Puerner' toxic criteria. BHT of antioxidant significantly increased cell viability severely damaged by $CdCl_2$-induced cytotoxicity in these cultures. In the protective effect of CM extract on $CdCl_2$-induced cytotoxicity, CM extract significantly increased cell viability, DPPH-free radical scavenging activity, SSA and inhibitory activity of LDH. From these results, it is suggested that oxidative stress is involved in the cytotoxicity of $CdCl_2$, and CM extract showed protective efficacy on $CdCl_2$-induced cytotoxicity via antioxidative effects. Conclusively, natural resources like CM extract may be a putative antioxidative agent for the detoxification or diminution of toxicity correlated with oxidative stress.

• Korean Journal of Environmental Biology
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• v.23 no.2 s.58
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• pp.206-213
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• 2005

The diurnal and seasonal variations of antioxidative enzyme activity and the O-J-I-P transients were investigated from the leaves of Crinum asiaticum var. japonicum under winter stress in natural habitat, in order to diagnose quantitatively physiological states of plants under stresses. The activities of superoxide dismutase and peroxidase increased slightly in winter. Especially, peroxidase acitivity was higher at dawn and night in winter and some isoforms were detected only in early winter. In the O-J-I-P transients, the fluorescence intensity of J, I, P steps decreased significantly in winter season, contrary to its high value in summer season. Of the chlorophyll fluorescence parameters derived from the O-J-I-P transients, Fm and $\Phi_{po}$ decreased with the increase of ABS/RC depending on temperature drop in winter.

• Journal of Food Hygiene and Safety
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• v.30 no.4
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• pp.383-389
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• 2015

This study was to examine the antioxidative activity of fermented Rhynchosia nulubilis (FRN) in obese rats. Oxidative stress due to reactive oxygen species (ROS) can cause oxidative damage to cells. Mitochondria are especially important in the oxidative stress as ROS have been found to be constantly generated as an endogen threat. Mitochondrial defense depends mainly on superoxide dismutase whereas microsomal defense depends on catalase, which is an enzyme abundant in microsomes. Seven weeks-aged female Sprague-Dawley rats were divided into four groups and fed high fat diets for 44 days. Also fermented Rhynchosia nulubilis was administered orally for 44 days at 7.5 ml/kg of body weight of rats. The antioxidative activities of fermented Rhynchosia nulubilis were measured by the superoxide dismutase, catalase, malondialdehyde levels in liver homogenate. The levels of malondialdehyde in FRN-treated groups were lower than those in obese groups. Superoxide dismutase and catalase levels were significantly increased. These results demonstrated that fermented Rhynchosia nulubilis had the inhibitive effects of oxidative stress in obese rats, suggesting that fermented Rhynchosia nulubilis would be used as an ingredient of the useful functional products.

• The Journal of Internal Korean Medicine
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• v.32 no.1
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• pp.56-67
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• 2011

Objectives : Recent etiological studies show that oxidative stress might play a major role in the diabetes and its complications. Mori Ramulus (MR) has been known to have antioxidative, anti-inflammatory and antidiabetic effects. The methanol extract of MR was tested for its effectiveness in LLC-PK1 cells exposed to high glucose. Methods : The cytoprotective effect of MR was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The antioxidative effect was measured in terms of generation amount of ${\cdot}O_2^-$ by 2',7'-dichlorodihydrofluorescein diacetate (DCFDA), NO by 4,5-diaminofluorescein (DAF-2), $ONOO^-$ by dihydrorhodamine 123 (DHR 123) in the high glucose -treated LLC-$PK_1$ cells. Western blotting was performed using anti-AGE, anti-RAGE, anti-MAPKs(ERK1/2, JNK, p38), anti-PI3K, anti-Akt, and anti-NF-${\kappa}$B (p50, p65) respectively. Results : MR extract reduced cell death and inhibited the generation of ${\cdot}O_2^-$, NO, $ONOO^-$ in the high glucose-treated LLC-$PK_1$ cells. MR inhibited the expression of AGE, RAGE, MAPKs, PI3K, and Akt by means of decreasing NF-${\kappa}$B activation. MR also inhibited NF-${\kappa}$B activation itself. Conclusions : These results indicate MR has cytoprotective, antioxidative, and anti-inflammatory effects. Therefore it is suggested that MR might prevent and cure diabetes and its complications.