• 대한본초학회지
• /
• 제21권4호
• /
• pp.143-148
• /
• 2006

Objectives : It is demonstrated that oxygen free radicals have cytotoxic effect on NIH3T3 fibroblast cells. Recently, many of herb extracts have an effect of antioxidant in oxygen free radical-induced cytotoxicity. But, the toxic mechanism of oxygen free radical is left unknown. The purpose of this study was to examine the cytotoxicity of hydrogen peroxide ($H_2O_2$) and antioxidant effect of Citri reticulatae pericarpium (CRP) on NIH3T3 fibroblasts. Methods : The cytotoxicy was measured by cell viability by XTT assay in NIH3T3 fibroblasts. XTT assay is regarded as a very sensitive screening method for the determination of the cell viability on various chemicals. Results : In this study, H2O2 decreased cell viability according to the dose- and time dependent manners after NIH3T3 fibroblasts were treated with various concentrations of H2O2 for 4 hours. And also, CRP showed the effect of antioxidant on $H_2O_2-induced $ cytotoxicity in cultured NIH3T3 fibroblasts. Conclusion : These results suggest that $H_2O_2$ has highly cytotoxic effect on cultured NIH3T3 fibroblasts by the decrease of cell viavility, and the herb extract such as CRP was showed the effect of antioxidant on $H_2O_2-induced$ cytotoxicity in these cultures.

• 대한한의학회지
• /
• 제25권3호
• /
• pp.32-44
• /
• 2004

Objectives : This study was undertaken to prove the effect of GSHT on the glutamate receptor, free radical and brain damage in rats subjected to brain ischemia Methods : Levels of cultured cortical neuron death caused by toxic chemicals were measured by LDH release assay. Neuroprotective effects of GSHT on brain tissues were examined in vivo by ischemic model of middle cerebral artery (MCA) occlusion. Results : GSHT showed significant inhibitory effect on LDH release induced by NMDA-kinate-Fe/sup 2+/. GSHT remarkably decreased coma duration time in a nonfatal dose of KCN and showed higher survival rate in a fatal dose. GSHT remarkably decreased ischemic area and edema induced by the MCA blood flow block. GSHT showed high improvement of forelimb and hind limb test after MCA occlusion in neurological examination. GSHT showed no significant change after MCA occlusion in pathological observation of the normal group. Conclusions : These results indicate that GSHT can be used to treat the brain damage caused by brain ischemia. Further study will be needed about the functional mechanism, etc.

• 한국식품영양과학회지
• /
• 제23권5호
• /
• pp.867-878
• /
• 1994

A general overview of the lipid peroxidation and its nutritional significance are presented ,with emphasis on the reaction mechaisms, peroxidized products, further interaction and nutritional/biological deterioration in a series of oxidative process. Overall mechanism with various factors and elements for initiation , propagation and termination of free radical reaction is reviewed and the primary /secondary products of peroxidized lipids are defined. Since these products are potentially reactive substances that can cause deterioration of proteins /amino acids and vitamins (carotene, tocopherols and ascorbic acid etc), mechanism and actual damages of their deterioration in some foods and biological models are outlined. Especially , chemical changes caused by interaction of peroxidized products (related hydroperoxides, radicals and malonaldehye etc) and protein are emphasized here. And also, the detailed mechanisms on radical scavenging of the these vitamins which are the most prominent natural antioxidants are presented . Additionally , the possible roles of peroxidicaed lipids and their secondary products in the process of aging an carcinogenesis are briefly discussed . However, it is important to not that more detailed and integrated studies on the reaction kinetics, energetics of peroxidation, their decomposed products , biochemical interaction potential damaging/aging / carcinogenic effects, protection from their oxidative spoilage and novel antioxidants in food and heterogeneous biological systems will be essential in order to assessing the implication of lipid peroxidation to human nutrition and health.

• 대한환경공학회지
• /
• 제31권8호
• /
• pp.627-634
• /
• 2009

본 연구는 염화 이온 ($Cl^-$)을 전해질로 이용하는 전기화학적 공정에서 생성되는 염소산화부산물인 클로레이트 ($ClO_3\;^-$, 염소산염)의 생성 메커니즘을 알아보기 위해 수행되었다. 우선, pH 및 초기농도에 따른 생성 특성을 살펴보았으며, 유리염소 생성과의 관련성 및 오존, OH 라디칼 등의 혼합산화제의 영향을 간접 평가하여 클로레이트의 생성 메커니즘을 구체화하였다. 그 결과, 클로레이트의 생성은 유리염소 (HOCl/$OCl^-$)의 전기화학적 반응을 주된 반응으로 하며, 염화 이온의 직접 양극산화 반응 및 OH 라디칼에 의한 경로가 있음을 확인하였다. 이어서 생성된 클로레이트가 퍼클로레이트로 산화되는 반응도 볼 수 있었다. 또한, 전극 간격에 따른 생성 농도를 유리염소 생성과 함께 평가하여, 유리염소 생성 효율은 극대화 시키되 클로레이트의 발생을 최소화 할 수 있는 최적조건을 찾는 방안을 제시하였다.

• Nuclear Engineering and Technology
• /
• 제8권3호
• /
• pp.159-168
• /
• 1976

Ceric 염과 ${\gamma}$-선을 계기로 하여 Nylon 직포에 Acrylic acid를 접목반응 시켰다. 접목반응된 Polyacrylic acid의 분자량 분포를 측정한 결과 양 평균분자량과 수 평균분자량의 비는 낮은온도(-184$^{\circ}C$)dptj 보다는 상온에서 더 높았다는 것을 알았다. Polyacrylic acid의 양 평규 sqnswkfid은 Sodium hydroxide용액에서 점도를 측정하여 계산하였다. Nylon에 Acrylic acid가 중합반응될 때에 중합반응에 영향을 주는 요소들을 시험하였다. Nylon의 산화반응은 질소원자에 인접해 있는 methlene group에서 일어나 free-radical이 만들어 진다는 메카니즘을 논의 하였다.

• Natural Product Sciences
• /
• 제14권4호
• /
• pp.239-243
• /
• 2008

Equisetum hyemale L. has been prescribed widely as a traditional medicine for the treatment of inflammatory diseases such as rheumatoid arthritis, conjunctivitis, pyelonephritis. In order to identification the mechanism, we examined an antioxidant and anti-inflammatory activity of 85% methanol extract of E. hyemale. In this study E. hyemale exhibited strong scavenging effect on 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical, superoxide radical, and nitric oxide. To elucidate the anti-inflammatory properties of E. hyemale, we investigated the inhibition effects of nitric oxide and IL-6 by E. hyemale in IFN-gamma and LPS-stimulated mouse peritoneal macrophages. E. hyemale suppressed nitric oxide, IL-6 production and iNOS expression dose-dependently without notable cytotoxic activity. These data suggest that E. hyemale might be useful in inflammatory diseases by inhibiting the free radicals and inflammatory mediators.

• Biomolecules & Therapeutics
• /
• 제10권4호
• /
• pp.211-217
• /
• 2002

Hepatoprotective activity of methanol extract of Angelica tenuissima Nakai on the $CCl_4$-induced hepatotoxicity was investigated. To elucidate the hepatoprotective activity and free radical scavenging effect, we examined alanine aminotransferase (ALT), aspartate aminotransferase (AST), albumin, total protein, cholesterol, malondialdehyde (MDA) levels in serum and activities of superoxide dismutase (SOD), catalase (CAT) in hepatic tissue as compared with those of carbon tetrachloride-induced rats. The action mechanism also has been estimated by quantative analysis of cytochrome P450 (CYP), NADPH-CYP reductase for phase I metabolism and glutathion (GSH), glutathion S-transferase (GST) level for phase II metabolsim. Treatment of Angelica tenuissima methanol extract significantly lowered the levels of alanine aminotransferase and aspartate aminotransferase. In addition, the levels of cholesterol, triglyceride, MDA, CAT were decreased, and SOD was activated. This result indicates that the hepatoprotective effect of Angelica tenuissima methanol extract on the CCl4-induced hepatotoxicity would be originated from reduction of the NADPH-CYP reductase, GSH and the enhancement of the activities of GST, CYP.

• Molecules and Cells
• /
• 제39권1호
• /
• pp.72-76
• /
• 2016

Cell death pathways such as apoptosis can be activated in response to oxidative stress, enabling the disposal of damaged cells. In contrast, controlled intracellular redox events are proposed to be a significant event during apoptosis signaling, regardless of the initiating stimulus. In this scenario oxidants act as second messengers, mediating the post-translational modification of specific regulatory proteins. The exact mechanism of this signaling is unclear, but increased understanding offers the potential to promote or inhibit apoptosis through modulating the redox environment of cells. Peroxiredoxins are thiol peroxidases that remove hydroperoxides, and are also emerging as important players in cellular redox signaling. This review discusses the potential role of peroxiredoxins in the regulation of apoptosis, and also their ability to act as biomarkers of redox changes during the initiation and progression of cell death.

• Journal of Applied Biological Chemistry
• /
• 제43권3호
• /
• pp.156-160
• /
• 2000

The possible mechanism of the DNA strand breaking activity of the hot-water extract of Fructus Chaenomelis (dried fruit of Chaenomeles sinensis) in a closed circular duplex replica form DNA (RFI DNA) was studied through agarose gel electrophresis under various conditions. Induction of DNA strand scission by the hot-water extract of C. sinensis occurred in dose and time-dependent manners. $Cu^{2+}$ was indispensable for the induction of DNA strand breakage. Exogeneous chelating agents inhibited the DNA breaking activity, conforming the catalytic action of $Cu^{2+}$ on generation of free radicals responsible for oxidative damage. Antioxidant enzymes and some radical scavengers were used to investigate the major radical species triggering the DNA strand scission, demonstrating that a highest inhibitory activity was found in the presence of catalase, while less in the presence of tiron (a scavenger for superoxide radical), 2-aminoethyl-isothiuroniumbromide-HBr, cysteamine (scavengers for hydroxyl radical), and 1,4-diazabicyclo [2,2,2] octane (a scavenger for singlet oxygen) in decreasing order. The findings implied that oxygen radical species generated in presence of transition divalent cation during the oxidation of some compounds contained in the hot-water extract of C. sinensis is mainly responsible for inducing genotoxicity.

• 한국식품위생안전성학회지
• /
• 제17권2호
• /
• pp.106-116
• /
• 2002

양강추출물 (Alpinia officinarum, 70% ethanol extract)과 함유 주성분인 galangirn은 프리라디칼소거작용과 지질과산화억제활성을 나타내었으며, $H_2O$$_2$ 또는 KO$_2$유도 세포독성에 대해서도 억제적으로 작용하여 세포보호효과를 나타내었다. DNA single strand breakage와 같은 산화적 스트레스에 대해서도 보호작용을 하고 있다. 또한, 마우스 소핵시험에 의하여 adriamycin과 같은 superoxide 우발물질에 의한 염색체 수준에서의 손상에 대해서도 억제효과를 나타내었다. 양강추출물은 galangin을 유효성분으로하여 산소프리라디칼들에 의한 산화적 손상에 억제적으로 작용하는 기전으로 산화적 스트레스에 대한 항노화, 암예방제로서의 응용가능성이 높은 추출물로서 향후 기능성 식품으로서의 응용가능성이 높을 것으로 판단되었다.