• Advances in Traditional Medicine
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• 제8권3호
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• pp.260-265
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• 2008

Annona reticulata belonging to the family Annonaceae is traditionally used as anthelmintic and it is reported to have anticancer activity. Free radicals are known to be involved in various types of diseases like cancer, diabetes, neurological disorders etc. The present study was aimed to evaluate free radical scavenging property of methanol extract of the leaves of Annona reticulata in some in vitro models e.g. DPPH, nitric oxide, superoxide and lipid peroxide radical model. The extract showed good dose-dependent free radical scavenging property in all the models. $IC_{50}$ values were found to be 3.22, 170.01, 25.12 and $140.12\;{\mu}g/ml$ respectively in DPPH, nitric oxide, superoxide and lipid peroxidation inhibition assays. Reductive ability of the extract was also tested based on potassium ferricyanide reduction where dose dependant reducing capability was observed. Measurement of total phenolic compounds by Folin-Ciocalteu's phenol reagent indicated that 1mg of the extract contained $146.20\;{\mu}g$ equivalent of pyrocatechol. The findings ascertain promising free radical scavenging property of the extract and the antioxidant property of the extract may be due to the high content of phenolic compounds.

• Advances in Traditional Medicine
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• 제6권3호
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• pp.167-173
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• 2006

A growing body of evidence supports lipid peroxidation as having a role in the pathogenesis of liver disease. Although the probable cause of damage to human hepatocytes may be multifactorial, free radicals have been implicated in a variety of liver diseases, particularly in the presence of iron overload and toxic substances such as ethanol. Consequently, antioxidants, particularly those of plant origin such as flavonoids, may help to reduce the risk of developing these diseases. Silybum (S.) marianum, a medicinal plant widely used in traditional European medicine for the treatment of liver disorders, was evaluated for antioxidant activity. Thin layer chromatography and High Performance Liquid Chromatography analyses of crude extract of the plant confirmed the presence of a number of flavonoids reported in the literature. The antioxidant activity of these flavonoids was measured through inhibition of lipid peroxidation and 1, 1-diphenyl-2- picrylhydrazyl radical scavenging. The crude plant extract showed marked antioxidant activity in both assays. These results suggest that S. marianum contains flavonoids with antioxidant activity, capable of inhibiting or scavenging free radicals, thus supporting its traditional use as a hepatoprotective agent.

• 동의생리병리학회지
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• 제25권1호
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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.

• Journal of Preventive Medicine and Public Health
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• 제20권2호
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• pp.221-227
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• 1987

In vivo ethane production in rats was used as an index of oxygen toxicity. The rats were allocated to four exposure conditions; hyperbaric oxygenation (HBO=5 ATA, 100% $O_2$), normobaric oxygenation (NBO=1 ATA,100% $O_2$), hyperbaric aeration (HBA=5 ATA, 21% $O_2$) and normobaric aeration (NBA=1 ATA, 21% $O_2$). After 120 minutes of exposure, the rats exposed to high concentration and/or high pressure oxygen exhaled significantly larger amounts of ethane than those exposed to NBA, and the differences in ethane production between any two groups were statistically significant (p<.01). This finding supports the hypothesis that hyperoxia increases oxygen free-radicals and the radicals produce ethane as a result of lipid peroxidation. It is notable that the ethane exhalation level of the HBA group was significantly higher than that of the NBO group. This difference could not be accounted for by the alveolar oxygen partial presure difference between the two groups.

• ALGAE
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• 제24권3호
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• pp.179-184
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• 2009

Methanol crude extract of the sea grass Zostera marina L. and organic solvent fractions (n-hexane, chloroform, ethyl acetate, n-butanol, and water) were screened for antioxidant activity (total phenolic contents, DPPH scavenging activity, and reducing power) and antimicrobial activity against three human skin pathogens, two bacteria and a yeast; Staphylococcus aureus, Staphylococcus epidermidis, and Candida albicans. Total phenolic contents and 2, 2- diphenyl-1-picrylhydrazyl (DPPH) scavenging activity were highest in the ethyl acetate fraction with 968.50 $\mu$g gallic acid equivalent per milligram of extract, and ca. 95% scavenging activity on the DPPH radicals at 10 mg $ml^{-1}$. In antimicrobial activity tests, MICs (Minimum Inhibitory Concentration) of each Zostera marina extract partitioned ranged from 1mg to 8 mg $ml^{-1}$ (extract/ 10% DMSO) against all three human skin pathogens. The MICs of the ethyl acetate and n-butanol fractions were the same with 1 mg $ml^{-1}$ against S. aureus and C. albicans. The ethyl acetate fraction of Z. marina does protect against free radicals and may be used to inhibit the growth of human skin pathogens.

• Nuclear Engineering and Technology
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• 제55권9호
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• pp.3183-3193
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• 2023

The water radiolysis in-core at light water reactors (LWRs) produces various radicals with other ionic species/molecules and radioactive nitrogen species in the reactor coolant. Nitrogen species can exist in many different chemical forms and recirculate in water and steam, and consequently contribute to what extent the environmental safety at nuclear power plants. Therefore, a clear understanding of formation kinetics and chemical behaviors of nitrogen species under irradiation is crucial for better insight into the characteristics of major radioactive species released to the main steam or relevant coolant systems and eventually development of advanced processes/methodologies to enhance the environmental safety at nuclear power plants. This paper thus focuses on basic principles on electrochemical interaction kinetics of radiolytic molecules and various nitrogen species in high temperature water, fundamental approaches for calculating thermodynamic values to predict their stability and domain in LWRs, and the effect of nitrogen species on crevice chemistry/corrosion and intergranular stress corrosion cracking (IGSCC) susceptibility of structure materials in high temperature water.

• Preventive Nutrition and Food Science
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• 제14권3호
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• pp.188-194
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• 2009

In this study, we evaluated the phytochemical compositions of the fruits of the pear cactus, mulberry, and Korean black raspberry to determine how they related to antioxidant capacity. Specifically, the total soluble polyphenol, flavonoid and anthocyanin contents were determined, and the phenolic compounds were evaluated by HPLC. In addition, the antioxidant capacity was evaluated by electron paramagnetic resonance (EPR), SOD-like activity and nitrate scavenging activity. Korean black raspberry was found to have the highest level of phytochemicals, followed by mulberry and pear cactus (p<0.05). Furthermore, EPR revealed that Korean black raspberry extract (100 ${\mu}g$/mL) removed 78.6% of the superoxide radicals in a xanthin-xanthin oxidase. Additionally, when the removal of hydroxyl radicals was evaluated, the extract of pear cactus showed 50% scavenging activity at 1000 ${\mu}g$/mL. Korean black raspberry extract showed the highest SOD-like activity, which was 44% (p<0.05). Finally, the nitrate scavenging activity of both extracts of mulberry and Korean black raspberry were found to be 93%, while that of the pear cactus was 63% at pH 1.2 (p<0.05).

• 대한약리학회지
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• 제21권2호
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• pp.79-89
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• 1985

심근 세포의 칼슘 조절에 중요한 역할을 하는 sarcoplasmic reticulum (SR)의 칼슘운반 능력이 허혈 심근에서 현저히 억제됨이 알려져 있다. 이와같은 허혈 심근에서의 SR 칼슘운반승력 저하에 유독성 산소 대사물이 관여할 것으로 생각되고 있으나 그 기전에 관하여는 아직 알려진 바 없다. 본 연구에서는 그 기전의 일단을 규명하기 위하여 산틴 산화효소계에 의하여 발생된 유독성 산소대사물긴 돼지 심실근에서 추출한 sarcoplasmic reticulum의 칼슘흡수 및 막지질 과산화, sulfhydryl group 그리고 단백질 변성에 미치는 영향을 관찰하여 다음과 같은 결과를 얻었다. 1) 산틴 산화 효소계와 반응시킨 sarcopl smic reticulum의 칼슘흡수는 반응시간 경과에 따라 현저히 억제되었다. 2) sarcoplasmic reticulum 막지질 과산화는 산딘 산화 효소계에 의하여 현저히 증가되었다 3) 항산화제 ${\beta}$-phenylenediamine은 막지질 과산화의 증가는 효과적으로 억제하였으나, 칼슘흡수 억제는 부분적으로 회복시켰다. 4) 산틴 산화 효소계에 의하여 SH-group은 현저히 감소되었으며, 항산화제 첨가에 의하여 그 감소가 일부 억제되었다. 5) sarcoplasmic reticulum을 DTNB로 처리하여 SH-group을 산소 대사물에 의한 산화반응으로부터 보호했을 경우 칼슘흡수의 억제가 부분적으로 방지되었다. 6) Sephadex G-200 크로마토그라피 상에서 산틴 산화효소계와 반응시킨 sarcoplasmic reticulum의 단백질분해가 관찰되었다. 7) 단백질의 polymerization은 관찰되지 않았으며, 아울러 polymerization을 억제하는 semicarbazide로 칼슘흡수 감소를 방지하지 못하였다. 이상의 결과에서 유독성 산소대사물에 의한 sarcoplasmic reticulum의 칼슘흡수 억제는 sarcoplasmic reticulum의 막지질 과산화, SH-group의 산화 및 막 반백절의 분해 등으로 초래되는 복합적인 기전으로 추정되었다.

• 한국자원식물학회지
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• 제23권1호
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• pp.38-46
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• 2010

메탄올을 용매로 12종 양치식물의 지상부와 근경의 건조시료를 초음파추출하여 페놀성 물질 함량 및 DPPH와 ABTS radical 소거능을 측정하였다. 총 폴리페놀의 함량은 건조시료 1 g에 $2.793{\sim}140.014\;mg{\cdot}g^{-1}$, 생시료 1 g에 $0.779{\sim}49.579\;mg{\cdot}g^{-1}$으로 다양하게 나타났으며, 넉줄고 사리와 더부살이고사리의 지상부에서 총 폴리페놀 함량이 높았다. 총 플라보노이드 함량은 건조시료 1 g에 $2.559{\sim}34.909\;mg{\cdot}g^{-1}$, 생시료 1g에 $0.714{\sim}11.487\;mg{\cdot}g^{-1}$으로 나타났다. 건조시료 중에는 관중 지상부, 생시료 중에는 더 부살이고사리의 지상부에서 총 플라보노이드 함량이 가장 높았다. 총 폴리페놀은 지상부보다 근경에 많이 함유된 경향을 보였으나, 총 플라보노이드는 지상부에 많았다. DPPH와 ABTS radical 소거능은 지상부보다 근경 추출물에서 높게 나타났다. 총 폴리페놀은 지상부보다 근경에 많이 함유된 경향을 보였으나, 총 플라보노이드는 지상부에서 함량이 많았다. DPPH와 ABTS radical 소거능은 지상부보다 근경 추출물에서 높게 나타났다. DPPH radical 소거능과 ABTS radical 소거능 모두 나도히초미 근경 추출물에서 가장 우수하였다. 그러나 시료의 수분함량과 추출수율을 고려하여 $RC_{50}$을 나타내는데 필요한 생시료의 양을 계산한 결과, 나도히초미 근경보다는 더부살이고사리 지상부가 DPPH와 ABTS radical 소거용 식물소재로 적합하였다. 양치식물의 추출물은 특히 ABTS radical 소거능이 매우 우수하였으며, 가지고비고사리 추출물을 제외한 대부분의 시료가 ascorbic acid 또는 BHT와 유사한 소거활성을 보였다.

• 생약학회지
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• 제38권2호통권149호
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• pp.164-169
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• 2007

ln our continued search for biologically active compounds from traditional medicine, we found that ethyl acetate fraction from Inonotus obliquus showed potent antioxidant activities on three different cell-free bioassay systems. Bioassay-directed chromatographic fractionation of the ethyl acetate fraction from Inonotus obliquus afforded four phenolic compounds, 4-(3,4-dihydroxyphenyl)-(E)-3-buten-2-one (1) , 3,4-dihydroxybenzaldehyde (2), protocatechuic acid (3) and caffeic acid (4) along with three sterols such as lanosterol (5), ergosterol peroxide (6) and 9,11-dehydroergosterol peroxide (7). Among isolates, phenolic compounds (1-4) were assessed for antioxidant activities. Almost phenolic compounds showed potent DPPH and superoxide anion radicals scavenging and lipid peroxidation inhibitory activities indicating that these phenolic compounds contribute to the antioxidative activities of I. obliquus. Compounds 2-3 and 7 were isolated for the first time from this plant.