• 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.

• 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.

• Journal of Physiology & Pathology in Korean Medicine
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• v.25 no.1
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• pp.115-121
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• 2011

This study was performed to investigate the antioxidant activity of extracts of black Panax ginseng (BGE) and its crude saponin (BGECS). The antioxidant activities of BGE and BGECS were evaluated for free radical scavenging activity against stable free radical (1,1-diphenyl-2-picrylhydrazyl) DPPH, nitrite, hydrogen peroxide and superoxide. In addition, the antioxidant activity of BGE and BGECS against peroxyl radicals, hydroxyl radicals and peroxynitrites were determined by the total oxy-radical scavenging capacity (TOSC) assay. As a result, BGE and BGECS were found to have a strong inhibitory activity with >90% against the DPPH radical at $1000{\mu}g/m{\ell}$ concentrations. Also, BGE and BGECS exhibited strong inhibitory activity with >80% against hydrogen peroxide at lower concentration ($125{\mu}g/m{\ell}$). Moreover, specific TOSC values (405 and 473 TOSC/mM) of BGE and BGECS against peroxynitrites were higher than GSH (347 TOSC/mM) used a positive control. These results suggest that BGE and BGECS could be useful to develop functional foods against disease related oxidative stress.

• The Journal of Korean Medicine
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• v.32 no.1
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• pp.141-150
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• 2011

Objectives: The aim of this study was to elucidate the antioxidant effect of solvent fractions of Angelica gigas root. Methods: The ethanol extract of Angelica gigas root was suspended in water and then partitioned with dichloromethane (MC Fr.), ethyl acetate (EA Fr.) and butanol (BuOH Fr.), sequentially. The antioxidant activities of solvent fractions of Angelica gigas root were evaluated for radical scavenging activity against stable free radicals (2,2-diphenyl-1-picrylhydrazyl) DPPH, hydrogen peroxide and superoxide anion radicals. In addition the antioxidant activities of solvent fractions of Angelica gigas root against peroxyl radicals, hydroxyl radicals and peroxynitrites were determined by the total oxy-radical scavenging capacity (TOSC) assay. Results: Among the solvent fractions of MC Fr., EA Fr., and BuOH Fr., BuOH Fr. was found to have stronger antioxidant activity with $IC_{50}$ values of 59.72, 14.36, 30.96 and $44.75\;{\mu}g/m{\ell}$ on the DPPH radical, nitrite, superoxide anion and hydrogen peroxide, respectively, than BHA used as a positive control. Moreover, specific TOSC values(564.8, 276.4 and 405.5 TOSC/mM) of BuOH fr. against peroxyl radicals, hydroxyl radical and peroxynitrite were 4 times higher than GSH (136.5, 67.4 102.6 TOSC/mM) used as a positive control. Conclusions: These results suggest that the BuOH fr. of Angelica gigas root has a high antioxidant activity and can be useful to develop functional food against oxidative stress conditions.

• Toxicological Research
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• v.26 no.4
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• pp.321-327
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• 2010

The ability of 80% ethanol extracts from five medicinal plants, Aralia continentalis, Paeonia suffruticosa, Magnolia denudata, Anemarrhena asphodeloides, and Schizonepeta tenuifolia, to neutralize hydroxyl radical, peroxyl radical and peroxynitrite was examined using the total oxyradical scavenging capacity (TOSC) assay. Peroxyl radical was generated from thermal homolysis of 2,2'-azobis(2-methylpropionamidine) dihydrochloride (ABAP); hydroxyl radical by an iron-ascorbate Fenton reaction; peroxynitrite by spontaneous decomposition of 3-morpholinosydnonimine N-ethylcarbamide (SIN-1). The oxidants generated react with $\alpha$-keto-$\gamma$-methiolbutyric acid (KMBA) to yield ethylene, and the TOSC of the substances tested is quantified from their ability to inhibit ethylene formation. Extracts from P. suffruticosa, M. denudata, and S. tenuifolia were determined to be potent peroxyl radical scavenging agents with a specific TOSC (sTOSC) being at least six-fold greater than that of glutathione (GSH). These three plants also showed sTOSCs toward peroxynitrite markedly greater than sTOSC of GSH, however, only P. suffruticosa revealed a significant hydroxyl radical scavenging capacity. Seven major active constituents isolated from P. suffruticosa, quercetin, (+)-catechin, methyl gallate, gallic acid, benzoic acid, benzoyl paeoniflorin and paeoniflorin, were determined for their antioxidant potential toward peroxynitrite, peroxyl and hydroxyl radicals. Quercetin, (+)-catechin, methyl gallate, and gallic acid exhibited sTOSCs 40~85 times greater than sTOSC of GSH. These four components also showed a peroxynitrite scavenging capacity higher than at least 10-fold of GSH. For antioxidant activity against hydroxyl radical, methyl gallate was greatest followed by gallic acid and quercetin. Further studies need to be conducted to substantiate the significance of scavenging a specific oxidant in the prevention of cellular injury and disease states caused by the reactive free radical species.

• 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.

• 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.

• Korean Journal of Ecology and Environment
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• v.41 no.4
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• pp.541-546
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• 2008

The purpose of this study was to evaluate ecosystem health effect in the physiological levels, based on ethoxyresorufin-O-deethylase (EROD) and total oxyradical scavenging capacity (TOSC) assays using sentinel fish species. We collected fish samples of Zacco platypus in May 2008 from 3 sampling sites including upstream, midstream, and downstream of the Gap Stream. EROD activity was averaged 4.54 in the downstream, 2.7 fold higher than upstream and indicated that stream condition was degraded along with longitudinal gradient from up to downstream. Downstream, especially was significantly increased (p < 0.01) so that indicated various pollutants including nutrient enrichment and toxicant exposure from the point sources, wastewater treatment plant and industrial complex may impact to the stream condition. In the mean time, TOSC assays showed higher in the midstream than other sites, but the values were not significant, compared to the previous report on oxidative stress. Overall results indicated that our approaches applying two biomarkers can be effectively used for diagnosis of the physiological levels in an integrative stream health assessments and can be applied as useful pre-warning techniques as a biochemical alarm system of organic pollutions.

• Journal of Physiology & Pathology in Korean Medicine
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• v.22 no.2
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• pp.397-402
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• 2008

The purpose of this study is to prepare black Panax ginseng leaf (PGL) and evaluate its antioxidative effect. In order to make black PGL, the raw PGL was successiely steamed at $95^{\circ}C$ for 3 hr nine times. The antioxidant activities of total saponins (Sa) from PGL and black PGL against peroxyl radicals and peroxynitrites were determined by the total oxy-radical scavenging capacity (TOSC) assay. Specific TOSC values for black PGL-Sa against peroxyl radicals and peroxynitrites were 2.3-fold and 2.1-fold of PGL-Sa, respectively, and 2.2-fold and 5.2-fold of glutathione, a positive control antioxidant, respectively. The black PGL-Sa exhibited stronger antioxidative effect than PGL-Sa. The main ginsenosides of black PGL were $Rg_3,\;Rk_1\;and\;Rg_5$. Among the saponins in black PGL, the amount of ginsenoside $Rg_3$ was examined by HPLC. 22.12 mg of ginsenoside $Rg_3$ was obtained from 1g of dried black PGL.

• Toxicological Research
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• v.17
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• pp.271-280
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• 2001

We report on the applicability oj a method recently developed in our laboratory for measuring the antioxidant potential of isolated chemicals and extracts derived from natural products. Peroxyl radicals generated by thermal homolysis of 2,2'-azobis-amidinopropane (ABAP) oxidize $\alpha$-keto-${\gamma}$-methiolbutyric acid (KMBA) to ethylene, which is monitored by gas chromatography. Inhibition of ethylene formation in the presence of antioxidants that compete with KMBA for peroxyl radicals is the basis of the Total Oxyradical Scavenging Capacity Assay (TOSCA; Winston et al., 1998). Antioxidative activities of water-soluble extracts of American green tea, the anti-hepatotoxic flavonolignan from milk thistle (Silybum marianum) silybin, Ginkgo biloba extract EGb 761, and a series of naturally occuring sesquiterpene lactones (all ger-macranolides found in in fungi, liverworts, and plants) were studied. The specific TOSC value per $\mu$M silybin was 5.2, which is essentially comparable to that of Trolo $x^{ⓡ}$, a water-soluble vitamine E analog. Tea and Ginkgo extracts exhibited potent peroxyl radical scavenging capacity with values, respectively of =1700 and 1000 $\mu$mols Trolo $x^{ⓡ}$ equivalent per gram dry matter. The known anti-inflammatory activity of some germacranolides prompted study of their antioxidant capacity. None of the lactones exhibited antioxidant capacity toward peroxyl radicals comparable to Trolo $x^{ⓡ}$; costunilide, the most lipophilic, had a TOSC value = to glutathione. The potential role of peroxyl radicals in lipidperoxidation, other cellular damage, and var-ious disease states suggest a possible preventive role for silybin, green tea and Ginkgo biloba in oxidative stress caused by these free radical species.ecies.