• Toxicological Research
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• v.23 no.2
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• pp.143-150
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• 2007

Although animal and epidemiological studies have suggested oxidative stress as an etiological factor in pathogenesis including cancer, inflammation, sepsis, fibrosis, cardiovascularlneurodegenerative diseases and aging-related disorders, conflicting results have been obtained in clinical trial with antioxidants. The reason for this discrepancy remains unknown but may be due, in part, to the lack of a validated assay system for evaluating antioxidant capacity. The antioxidant activity of a series of sugar alcohols against peroxyl radicals, hydroxyl radicals and peroxynitrites was determined by the total oxy-radical scavenging capacity (TOSC) assay and cell-based assay using H4IIE cells. Specific TOSC values calculated from the slope of the linear regression for erythritol, xylitol, sorbitol or mannitol against peroxyl radicals was $2.1{\pm}0.2,\;3.7{\pm}0.3,\;9.1{\pm}0.3$ or $8.7{\pm}1.1$ TOSC/mM, respectively. Specific TOSC values for erythritol, xylitol, sorbitol or mannitol against peroxynitrite was $1.9{\pm}0.3,\;3.9{\pm}0.4,\;7.8{\pm}0.7$ or $7.7{\pm}0.5$ TOSC/mM, respectively. These results suggest that oxy-radical scavenging capacity is dependent on the number of aliphatic hydroxyl group in sugar alcohols of monosaccharide. Tert-butylhydroperoxide (t-BHP)-induced cell toxicity determined by MTT assay was marginally attenuated by 10 mM erythritol, but completely inhibited by 10 mM xylitol, 2 mM sorbitol or 0.75 mM maltitol, a disaccharide alcohol. Oxidative stress markers, such as glutathione (GSH) and malondial-dehyde (MDA) levels, were measured in t-BHP-treated cells using HPLC equipped with a fluorescence detector and a reverse phase column. Erythritol did not change the levels of GSH and MDA in H411E cells treated with t-BHP. The t-BHP-induced changes in cellular GSH and MDA levels were ameliorated by 10 mM xylitol and completely blocked by 10 mM sorbitol and maltitol. These results indicate that sugar alcohols protect cells against oxidative stress via scavenging oxy-radical and suggest that TOSC assay in conjunction with cell-based assay is a valid method for evaluating antioxidant capacity of natural and synthetic chemicals.

• Korean Journal of Plant Resources
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• v.23 no.5
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• pp.445-450
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• 2010

This study was carried out to investigate the antioxidative capacity of Ampelopsis brevipedunculata 95% ethanol extracts. The concentration of A. brevipedunculata extract at which DPPH radical scavenging activity was inhibited by 50% was 0.42 mg/mL as compared to 100% by pyrogallol as a reference. Total antioxidant status was examined by total antioxidant capacity against ABTS radical reactions. Total antioxidant capacities of A. brevipedunculata extract at the concentrations of 0.1 and 1 mg/mL were 0.65 and 3.71 mM Trolox equivalents, respectively. Oxygen radical absorbance capacities of A. brevipedunculata extract at the concentrations of 5 and $100\;{\mu}g/mL$ were 22.75 and $131.25\;{\mu}M$ gallic acid equivalents, respectively. Superoxide scavenging activities of A. brevipedunculata extract at the concentrations of 0.1 and 1 mg/mL were 27.7 and 56.0%, respectively. Total phenolic contents of A. brevipedunculata extract at the concentrations of 0.5 and 2.0 mg/mL were 0.55 and 2.06 mM gallic acid equivalents, respectively. A. brevipedunculata extract at the concentration of 0.1 mg/mL inhibited 0.2 mM and 0.5 mM tert-butyl hydroperoxide induced cyototoxicity by 36.2 and 23.3%, respectively, in HepG2 cell culture system. Thus strong antioxidant and cytotoxicity-inhibiting effects of A. brevipedunculata extract seem to be due to, at least in part, the prevention from free radicals-induced oxidation as well as high levels in total phenolic contents.

• Natural Product Sciences
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• v.20 no.3
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• pp.176-181
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• 2014

The antioxidant activities of 29 components isolated from the aerial parts of Artemisia iwayomogi were evaluated in vitro and in cell culture. Among the tested compounds, 2, 6, 8, 10, 13, and 14 exhibited the greatest peroxyl radical-scavenging activities in the oxygen radical absorbance capacity (ORAC) assay, and 2, 10, and 14 also showed significant reducing capacities. However, all compounds showed weak metal chelating activities. Their cellular antioxidant activities were evaluated in HepG2 cells. At $10{\mu}M$, compounds 6, 8, and 14 exhibited stronger protection against 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH)-induced oxidative stress than compounds 2, 10, and 13. Moreover, Compounds 2 and 8 were more effective in protecting against $Cu^{2+}$-induced oxidative stress than compounds 6, 10, 13, and 14 at $10{\mu}M$. These results suggest that the phenolic compounds in A. iwayomogi have the potential to be developed as natural antioxidants for the treatment of oxidative stress-related diseases.

• Food Science and Biotechnology
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• v.14 no.1
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• pp.123-130
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• 2005

Hydrogen-donating capacity, scavenging activity of reactive oxygen including superoxide anion radical and hydrogen peroxide, metal-chelating activity, and reducing power of garlic extracts were investigated. All tested garlic extracts exhibited in vitro antioxidant activities, with Uiseong extract showing highest hydrogen-donating and hydrogen peroxide-scavenging activities, and reducing power, followed by Seosan and Samchek extracts, in proportion to total thiosulfinate contents. Higher scavenging activity of superoxide anion radical was observed in Uiseong than Seosan and Samchek extracts. Metal-chelating activity increased in order of Uiseong < Seosan < Samchek, showing inverse relations to total thiosulfinate content. Garlic extracts of Uiseong and Seosan showed weak prooxidant activities and that of Samchek showed strong antioxidant activity against $Cu^{+2}$-induced human LDL oxidation. Protective effects on peroxyl and hydroxyl radical-induced DNA strand damages were observed in all tested garlic cloves. These results indicate growing conditions of garlic cloves affect total thiosulfinate content and antioxidant activities.

• Preventive Nutrition and Food Science
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• v.12 no.4
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• pp.191-196
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• 2007

We investigated radical scavenging effects and protective activities of fucoidan and alginic acid, active polysaccharide components from brown seaweeds, against peroxyl radical-induced oxidative stress under in vitro and cellular system. Fucoidan exerted strong radical scavenging effects against nitric oxide (NO) and superoxide anion $(O_2)$. On the other hand, alginic acid did not show inhibitory activity against NO and relatively weak $O_2{^-}$ scavenging effect. Additionally, alginic acid exhibited higher hydroxyl scavenging activity than fucoidan. Both fucoidan and alginic acid significantly enhanced cell viability against oxidative stress induced by 2,2'-azobis(2-amidinopropane)dihydrochloride (AAPH). At $1000{\mu}g/mL$ concentration of fucoidan and alginic acid, the viability was increased from 16.4% to 85.9% and 67.7%, respectively. In addition, fucoidan and alginic acid ameliorated the lipid peroxidation in LLC-PK1 cell induced by AAPH in a dose-dependent manner. In particular, fucoidan showed stronger inhibitory effect than alginic acid in the cellular system. The present study suggests that fucoidan and alginic acid may be promising antioxidants against oxidative stress induced by free radicals.

• Korean Journal of Agricultural Science
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• v.38 no.4
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• pp.717-722
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• 2011

In this study, we investigated the antioxidant activity of hesperidin and hesperetin, which are the active compounds from Citrus junos, in the cellular system. Under cellular model of oxidative damage using LLC-$PK_1$ renal epithelial cell, the oxidative damage induced by 2,2'-azobis (2-amidinopropane) dihydrochloride (AAPH) led to the loss of cell viability, while treatment of hesperidin and hesperetin increased significantly the cell viability as dose-dependent manner. In addition, NO-induced cellular oxidative damage by sodium nitroprusside were significantly recovered by the treatment of hesperidin and hesperetin, showing the increase of cell viability. But hesperidin and hesperetin showed no significant protective effect on $O_2{^-}$-induced cellular oxidative damage. The present study indicates that hesperidin and hesperetin protect against free radical, especially AAPH-induced peroxyl radical. In particular, hesperetin has stronger protective effect against oxidative stress than hesperidin.

• The Korean Journal of Food And Nutrition
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• v.26 no.1
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• pp.150-153
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• 2013

The objective of this research was to compare the antioxidant activities of meat broths served with oriental noodles. For this purpose, we estimated DPPH, ABTS radical scavenging, and SOD-like activities as well as reducing power of meat broth of oriental noodles such as Korean, Chinese and Japanese style. DPPH radical scavenging activities of Korean, Chinese and Japanese meat broth at the concentration of 2 $mg/m{\ell}$ were 2.78%, 25.37%, and 40.74%, respectively. The Korean and Chinese meat broths exhibited little hydroxyl radical scavenging activities, whereas Japanese broth showed 59.06% hydroxyl radical scavenging activity at the concentration of 0.5 $mg/m{\ell}$. The peroxy radical scavenging activities ($IC_{50}$) of Korean, Chinese and Japanese meat broth were 0.121 $mg/m{\ell}$, 0.222 $mg/m{\ell}$, and 0.013 $mg/m{\ell}$, respectively. The Korean and Japanese meat broth exhibited higher ABTS radical scavenging activity than that of Chinese.

• Biotechnology and Bioprocess Engineering:BBE
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• v.5 no.5
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• pp.366-371
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• 2000

The aim of this study was to investigate the efficiency of the pentagalloic acid compound in inhibiting the metal ions and cell lines that mediate in low density lipoprotein (LDL) oxidation. Pentagalloic acid prolonged the lag time preceeding the onset of conjugated diene formation. In chemically induced LDL oxidation by Cu$^2$(sup)+ plus hydrogen peroxide or peroxyl radical generated by 2, 2-azo-vis (2-amidino propane) hydrochloride (AAPH), pentagalloic acid inhibited LDL oxidation as monitored by measuring the thiobarbituric acid reactive substances(TBARS), malondialdehyde(MDA), and gel electrophoretic mobility. The physiological relevance of the antioxidative activity was validated at the cellular level where pentagalloic acid inhibited mouse macrophage J774 and endothelial cell-mediated LDL oxidation. When compared with several other antioxidants, pentagalloic acid showed a much higher ability than naturally occuring antioxidants, ${\alpha}$-tocopherol and ascorbic acid, and the synthetic antioxidant, probucol.

• Biomolecules & Therapeutics
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• v.21 no.2
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• pp.146-152
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• 2013

This study examined the total polyphenol content of eight wild edible plants from Ethiopia and their effect on NO production in Raw264.7 cells. Owing to its relatively high polyphenol concentration and inhibition of NO production, the methanol extract of Adansonia digitata L. leaf (MEAD) was subjected to detailed evaluation of its antioxidant and anti-inflammatory effects. Antioxidant effects were assessed by measuring free-radical-scavenging activity using 1,1-diphenyl-2-picrylhydrazyl (DPPH) and oxygen-radical-absorbance capacity (ORAC) assays, while anti-inflammatory effects were assessed by measuring inducible nitric oxide synthase (iNOS) expression in lipopolysaccharide (LPS)-stimulated RAW264.7 cells. In the ORAC assay, MEAD was 10.2 times more potent than vitamin C at eliminating peroxyl radicals. In DPPH assay, MEAD also showed a strong ROS scavenging effect. MEAD significantly inhibited iNOS activity ($IC_{50}=28.6{\mu}g/ml$) of LPS-stimulated Raw264.7 cells. We also investigated the relationship between iNOS expression and nuclear factor kappa B (NF-${\kappa}B$) activation. MEAD inhibited $I{\kappa}B{\alpha}$ degradation and NF-${\kappa}B$ translocation from the cytosol to the nucleus in LPS-induced RAW264.7 cells without significant cytotoxic effects, as confirmed by MTT assay. These results suggest that MEAD inhibits anti-inflammatory iNOS expression, which might be related to the elimination of peroxyl radicals and thus the inhibition of $I{\kappa}B{\alpha}$-mediated NF-${\kappa}B$ signal transduction.

• Environmental Analysis Health and Toxicology
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• v.25 no.1
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• pp.85-94
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• 2010

Platycodon grandiflorum, Doraji as Korean name, is one of the most widely used traditional oriental medicine for bronchial diseases and also used as a folk remedy for geriatric diseases and inflammatory diseases. In recent studies, it has been reported that some effect of P. grandiflorum is derived from its antioxidant activity, although there is still a lack of evidence to establish its oxy-radical scavenging activity. In this study, total oxy-radical scavenging capacity (TOSC) assay was used to evaluate antioxidant activity of total extracts (T-PG), polysaccharide fraction (Po-PG), and saponin fraction (Sa-PG) isolated from P. grandiflorum against peroxyl radicals and peroxynitrites. And MTT assay was taken to assess cyto-protective effects of T-PG, Po-PG and Sa-PG in H4IIE cells treated with hydrogen peroxide and tert-butylhydroperoxide. In the TOSC assay, Sa-PG showed strong oxy-radical scavenging capacity compared with T-PG and Po-PG. In cell-based assay, T-PG and Po-PG protected cells from oxidative stress, but Sa-PG did not protect cells because of cytotoxicity of Sa-PG. These results suggest that the saponin components of P. grandiflorum have relatively strong antioxidant capacity and cytotoxicity in rat hepatoma cells.