Studies on Free Radical EPR,Superoxide Dismutase Water-soluble Lipidperoxide in Tears

By means of electron paramagnetic resonance(EPR), chemistry luminescence and fluorescent spectroscopy, the free radical, superoxide dismutase and water soluble lipid peroxide in tears of normal eyes(150 eyes, 100 cases), Moorens ulcer(9 eyes), coreal grafts rejection(16 eyes) were studied. The results showed that the spin density of the free radical was 36(±058)×1012 spins/mL tear, the content of the superoxide dismutase(SOD) was 384(±145) ng/mL tear, the opposite fluorescent density of the water soluble lipid peroxide was 12912(±1691) U/mL tear in normal tears. The normal values are 25—48×1012 spins/mL tear for free radical, 239—529 ng/mL tear for SOD, 9598—16225 U/mL tear for water soluble lipid peroxide. There are significant differences in different eyes, different sexes and different ages. The free radical and lipid peroxide are higher obviously in the tears of patients with Moorens ulcer and rejected corneal grafts, compared with those of the normal control subjects(P<001), SOD is lower evidently(P<001). The above fact shows the pathogenic mechanism of Moorens ulcer and keractoplasty rejection is significantly related to toxicities injuring effect of the free radical. These results have provided important experimental data for studying lacrimalogy and new methods for clinical diagnosis and treatrment.

Effects of Water─soluble Components Isolated from Salviamilltiorrhiza on Oxygen Free Radical Generation and LipidPeroxidation

The effects of water─soluble components isolated from Salvia miltiorrhiza on oxygen free radical prodction and lipid peroxidation were estimated. Five components(10 μmol/L)were shown to inhibit superoxide anion generation by xanthine─xanthine oxidase system. It was also demonstrated that six components( 100 μmol/L) prevented H_2O_2─induced hemolysis and MDA fonnation in mouse erythrocytes.The effects of Sal A, Sal B, Sal C and Ros A were dose dependent. In Langendorff rat heart, pretreatment with Sal A 20μmol/L significantly prevented MDA production induced by 30 min reoxygenation after 45 min anoxia.The results indicated that there were also other potent antioxidant componentts in Salvia milliorrhiza besides Dphl and Pal. The protection of Sal A against myocardial anoxiareoxygenation inury may be mainly ascribed to its oxygen free radical scavenging activity.

Antioxidant,lipid peroxidation inhibition and free radical scavenging efficacy of a diterpenoid compound sugiol isolated from Metasequoia glyptostroboides

Objective:To investigate the antioxidant enicacy of a biologically active dilerpenoid compound sugiol isolated from Metasequoia glyptostroboides(M.glyptostroboides)in various antioxidant models.Methods:An abietane type diterpenoid sugiol,isolated from ethyl acetate extract of M.glyptostroboides cones,was analyzed for its antioxidant efficacy as reducing power ability and lipid peroxidation inhibition as well as its ability to scavenge free radicals such as 1,1-diphenyl-2-picryl hydrazyl,nitric oxide,superoxide and hydroxyl radicals.Results:The sugiol showed significant and concentration-dependent antioxidant and free radical scavenging activities.Consequently,the sugiol exerted lipid peroxidation inhibitory effect by 76.3%as compared to a-tocopherol(80.13%)and butylaled hydroxyanisole(76.59%).In addition,the sugiol had significant scavenging activities of l,l-diphenyl-2-picryl hydrazyl,nitric oxide,superoxide and hydroxyl free radicals in a concentration-dependent manner by 78.83%,72.42%,72.99%and 85.04%,when compared to the standard compound ascorbic acid(81.69%,74.62%,73.00%and 73.79%)and a-tocopherol/butylated hydroxyanisole(84.09%,78.61%,74.45%and 70.02%),respectively.Conclusions:These findings justify the biological and traditional uses of M.glyptostroboides or its secondary metabolites as confirmed by its promising antioxidant efficacy.

Evaluation of lipid peroxidation inhibition and free radical scavenging abilities of 5,6,7-trimethoxy dihydroflavonols

Four naturally rare 5,6,7-trimethoxy-2,3-cis-dihydroflavonols （3-6） and two 5,6,7-trimethoxy-2,3-trans-dihydroflavonols （7-8） were designed and synthesized. Their antioxidative properties were evaluated by way of examining their scavenging capacities towards DPPH and O2^＊- free radicals, as well as by measuring their inhibitory ability against LPO. Both the 2,3-trans and the 2,3- cis conformers exhibited certain quenching abilities to DPPH and O2^＊- radicals, while most of the synthetic dihydroflavonols demonstrated remarkable inhibition to LPO.

高维生素C刺梨饼干配方工艺优化及其体外抗氧化作用

以刺梨为基本原料,制作一款高维生素C(VC)含量的刺梨饼干,并对其配方工艺进行优化,对其体外抗氧化活性进行评价.采用4因素4水平正交试验设计,对影响刺梨饼干制作中VC含量和稳定性的4个关键因素烘焙温度、烘焙时间、苹果酸用量和红花籽油用量进行优化;采用不同种类的普通食用油等量替代优化配方中的红花籽油,观察并对比普通食用油和红花籽油对产品中VC含量的影响;通过测定产品对羟基自由基和超氧阴离子自由基的清除率及对脂质过氧化的抑制率来评价产品的体外抗氧化活性.结果得到最优的产品配方工艺条件为:烘焙温度为140℃,烘焙时间为20 min,苹果酸用量为0.75%,红花籽油用量为8%.产品中的红花籽油采用普通食用油替代后,起酥油的VC损失率最大,比红花籽油高4.8倍以上,普通植物食用油的VC损失率也比红花籽油高89%以上.按优化后的配方工艺制得的刺梨饼干产品中VC含量达210 mg/100 g,质量稳定.优化后的产品和等剂量VC对照组对羟基自由基和超氧阴离子自由基都有良好的清除作用,对脂质过氧化有良好的抑制作用,并且优化后的产品效果都显著优于等剂量的VC对照组.

体外模拟胃肠消化过程中云南金花茶抗氧化能力变化

为探究云南金花茶在消化过程中总黄酮、总多酚释放及功能活性的变化情况,该研究采用体外模拟胃肠消化模型测定了云南金花茶消化液中总黄酮、总多酚浓度及自由基清除能力、铁离子还原能力和脂质过氧化抑制能力,并对其进行了相关性分析。结果表明,模拟胃消化过程中,云南金花茶总黄酮、总多酚含量均比口腔消化高,最高分别达229.99、327.65µg/mL,经肠消化后,总黄酮含量在38.56~78.88µg/mL之间,总多酚含量在30.04~65.52µg/mL之间,含量较低。在功能活性测定中,较口腔消化,胃消化阶段的DPPH·、ABTS+·清除能力和铁离子还原能力显著升高,脂质过氧化抑制能力随消化的进行呈上下波动;经肠消化后,DPPH·、ABTS+·清除能力和铁离子还原能力急剧下降,且均比胃消化阶段低,而脂质过氧化抑制能力则趋于平稳或逐渐上升。通过相关性及主成分分析,各指标之间存在一定的关联性。综上所述,云南金花茶是较好的活性物质来源,该研究可为探索云南金花茶在人体消化过程中活性物质的变化及作用机制提供一定的实验基础和新思路。

变应性皮肤病人血过氧化脂质与IgE水平变化

测定了４５例变应性皮肤病人的血浆过氧化脂质（ＬＰＯ）以及血ＩｇＥ含量。结果显示，患者血ＬＰＯ和ＩｇＥ含量均显著高于正常对照组（Ｐ＜０．０１及Ｐ＜０．０５）。患者血ＩｇＥ水平升高与ＬＰＯ变化是正相关关系（ｒ＝０．７１，Ｐ＜０．００５）。提示在变应性皮肤病的病理过程中，ＩｇＥ所介导的过敏反应可能与自由基脂质过氧化损伤有关。

Mechanisms of Inhibitory Effects of Breviscapine on Lipid Peroxidation in Rat Brain Mitochondria

The mechanisms by which breviscapine (Bre) inhibits the lipid preoxidation in rat brain mitochondria were investigated. The mitochondrial lipid peroxidation of rat brain induced by oxygen free radical was measured by thiobarbituric acid spectrophotometry. The chelating activities of Bre for Fe 2+ were tested by differential spectrum. Superoxide anion (O 2)from xanthine xanthine oxidase (Xan XO) system and hydroxyl radical (·OH) from FeSO 4 H 2O 2 system were determined with spectrophotometry. It was found that Bre could effectively inhibit the lipid peroxidation of brain mitochondria induced by free radicals driven from Xan XO and FeSO 4 H 2O 2 system. The IC 50 of Bre were 93 01 μmol·L -1 for Xan XO system and 62 18 μmol·L -1 for FeSO 4 H 2O 2 system. Bre also scavenged O 2 and ·OH produced by Xan XO and FeSO 4 H 2O 2 systems. The IC 50 of Bre were 32 63 μmol·L -1 for O - 2 and 20 22 μmol·L -1 for ·OH. Furthermore, the chelating Fe 2+ activity of Bre was shown. It may be concluded that Bre inhibited lipid peroxidation at different stages of the reaction of oxygen free redial with the mitochondria membrane: (1) the formation of ·OH; (2) the initiation of the lipid peroxidation, by chelating Fe 2+ and scavenging O 2 as well as ·OH. The scavenging oxygen free radicals and chelating iron are the mechanisms of inhibitory effect of Bre on lipid peroxidation.

Reduction of hydrogen peroxide-induced erythrocyte damage by Carica papaya leaf extract

Objective:To investigate thein vitroantioxidant potential of Carica papaya(C. papaya) leaf extract and its effect on hydrogen peroxide-induced erythrocyte damage assessed by haemolysis and lipid peroxidation.Methods:Hydroxyl radical scavenging activities, hydrogen ion scavenging activity, metal chelating activity, and the ferrous ion reducing ability were assessed as antioxidant indices. In the other experiment, human erythrocytes were treated with hydrogen peroxide to induce erythrocyte damage. The extract(at various concentrations) was subsequently incubated with the erythrocytes and later analysed for haemolysis and lipid peroxidation as indices for erythrocyte damage.Results:Preliminary investigation of the extract showed that the leaf possessed significant antioxidant and free radical scavenging abilities usingin vitro models in a concentration dependent manner(P<0.05). The extract also reduced hydrogen peroxide induced erythrocyte haemolysis and lipid peroxidation significantly when compared with ascorbic acid(P<0.05). The IC50values were 7.33 mg/mL and 1.58 mg/mL for inhibition of haemolysis and lipid peroxidation, respectively. In all cases, ascorbic acid(the reference antioxidant) possessed higher activity than the extract.Conclusions:The findings show that C. papayaleaves possess significant bioactive potential which is attributed to the phytochemicals which act in synergy.Thus, the leaves can be exploited for pharmaceutical and nutritional purposes.

Radical scavenging and antibacterial activity of Arnebia benthamii methanol extract

Objective:To evaluate in vitro antioxidant and antibacterial activity of methanolic extract of Arnebia benthamii（A.benthamii） whole plant.Methods:Plasmid damage was analyzed by agarose gell electrophoresis.Calf thymus DNA was monitored by TBARS formation.DPPH, reducing power and lipid peroxidation was evaluated by using standard procedures.Antibacterial assay was monitored by disc diffusion method.Results:DPPH radical scavenging and hydroxyl radical scavenging potential of the plant revealed that the extract to be active radical scavenger.Reducing(Fe3+-Fe2+) power and lipid peroxidation inhibition efficiency（TBARS assay） of the extract was also evaluated and the extract showed promising activity in preventing lipid peroxidation and might prevent oxidative damages to biomolecules.The extract offered a significant protection against plasmid and calf thymus UNA damage induced by hydroxyl radicals. The extract was also evaluated on different bacterial strains and the maximum antibacterial activity was exhibited against Escherichia coli（E.coli） when compared with standard drug. Conclusions:These findings demonstrate that the methanol extract of A.benthamii has excellent anti-oxidant activities and could be considered as a potential source of lead molecules for pharmaceutical industries.

Estrogen inhibits lipid peroxidation after hypoxic-ischemic brain damage in neonatal rats

Sprague-Dawley neonatal rats within 7 days after birth were used in this study. The left common carotid artery was occluded and rats were housed in an 8% O2 environment for 2 hours to establish a hypoxic-ischemic brain damage model. 17β-estradiol （1 × 10-5 M） was injected into the rat abdominal cavity after the model was successfully established. The left hemisphere was obtained at 12, 24, 48, 72 hours after operation. Results showed that malondialdehyde content in the left brain of neonatal rats gradually increased as modeling time prolonged, while malondialdehyde content of 17β-estrodial-treated rats significantly declined by 24 hours, reached lowest levels at 48 hours, and then peaked at 72 hours after injury. Nicotinamide-adenine dinucleotide phosphate histochemical staining showed the nitric oxide synthase-positive cells and fibers dyed blue/violet and were mainly distributed in the cortex, hippocampus and medial septal nuclei. The number of nitric oxide synthase-positive cells peaked at 48 hours and significantly decreased after 17β-estrodial treatment. Our experimental findings indicate that estrogen plays a protective role following hypoxic-ischemic brain damage by alleviating lipid peroxidation through reducing the expression of nitric oxide synthase and the content of malondialdehyde.

CLINICAL SIGNIFICANCE OF VITAMIN C TO AMELIORATE LIPID PEROXIDATION DAMAGE IN CORONARY ARTERY DISEASE

The activities of superoxide dismutase (SOD). glutathione peroxidase (GSH-PX) in blood and the content of melondialdehyde (MDA) in plasma of 30 Fatients (male 17, female 13) with coronary artery disease (CAD) were determined in this study. It was shown that SOD and GSH-PX activities were decreased and the content of MDA was increased in the Patients comparative with the healthy controls (P<0.001). Vitamin C, the free radical scavenger, was then administered intravenously with a daily dose of 2g for 2 weeks. The activities of SOD and GSB-PX were significantly elevated (P<0.01, and P<0.05, respectively). and the level of MDA was obviously declined (P<0.01). Thus,the lipid peroxidation is involved in the pathogenesis of CAD,and vitamin C possessing some effects to ameliorate the lipid peroxidation damage could be helpful in the treatment of CAE.

EFfect of verbascoside on decreasing concentration of oxygen free radicals and lipid peroxidation in skeletal muscle

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Relationship Between Membrane Damage Induced by Osmotic Stress and Lipid Peroxidation and Some Free Radicals

To treat leaf discs with solutions of various osmotic potentials of polyethylene glycols (MW 6000) by adopting the floating treatment could increase the membrane permeability, decrease the formation of malondialdehyde,and reduce the activity of peroxidase. Nevertheless, the activities of superoxide dismutase and catalase were not obviously altered. In verifying if the membrane damage was caused by lipid peroxidation initiated by active oxygen species, diethyldithiocarbamate was chosen as inhibitor superoxide dismutase,aminotriazole as catalase and mannitol as scavenger of hydroxyl free radicals.The results have shown that there is not any correlation between lipid peroxidation and membrane damage.Therefore,membrane damage caused by water stress is probably not due to free radical initiation.

二氢杨梅素抗脂质过氧化作用的研究

目的 :研究二氢杨梅素 (DMY)抗脂质过氧化作用。方法 :采用分光光度法测定DMY对由Fe2 + 维生素C(Fe2 + VitC)体系、Fe2 + 过氧化氢 (Fe2 + H2 O2 )体系、Fe 半胱氨酸 (Fe2 + Cys)体系诱导的脂质过氧化的抑制作用。结果 :DMY能抑制离体大鼠脑、心、肝匀浆及线粒体脂质过氧化并表现出剂量依赖关系。结论 :DMY具有较好的抗脂质过氧化作用 ,具有进一步研究与开发价值。

不同种类蜂蜜抗氧化活性的研究

本文以5种不同蜜源的蜂蜜为研究对象,在测定其总酚酸含量的基础上,研究了蜂蜜对DPPH自由基、超氧阴离子自由基、羟基自由基、脂质过氧化的清除作用,同时还测定了蜂蜜的总还原力。实验结果表明,5种蜂蜜均有显著的抗氧化性,呈剂量效应关系,酚酸含量、还原能力、抗氧化能力之间呈正相关,酚酸含量较高的枇杷蜜和荆条蜜的抗氧化能力较强。

白藜芦醇的体外抗氧化活性

通过对DPPH自由基、ABTS+.的清除能力和还原力的测定,探讨白藜芦醇的抗氧化活性;并采用过氧化氢诱导红细胞自氧化模型和肝组织脂质过氧化反应模型,探讨白藜芦醇对自由基损伤和脂质过氧化反应的抑制作用。结果显示,白藜芦醇具有很强的清除自由基和抑制自由基引起的氧化损伤的能力。

甘草类黄酮对脂质过氧化和活性氧自由基的作用

本文用比色法测定过氧化脂质研究甘草类黄酮(FG)的抗脂质过氧化作用,并用化学发光法和自旋捕集技术检测该药对O_2^(?)和OH~·的清除作用。体外实验表明:FG 2.8～25μg/ml可明显抑制小鼠肝匀浆在振荡温育条件下引起的丙二醛升高;FG 0.265～26.5μg/ml或2.58～258 μg/ml分别对碱性二甲基亚砜或黄嘌呤/黄嘌呤氧化酶体系生成的O_2^(?)有显著清除作用;以上作用呈浓度依赖性变化。FG 144 μg/ml或258 μg/ml分别对PMA刺激多形核白细胞释放的O_2^(?)及OH~·或Fenton's反应生成的OH~·有明显清除作用。实验证明FG有抗氧化作用。

青藤碱清除氧自由基和抗脂质过氧化作用

目的研究青藤碱体外清除氧自由基与抗脂质过氧化的作用。方法超氧阴离子自由基(O2÷)由邻苯三酚自氧化法产生,采用F en ton体系产生羟自由基(.OH),研究青藤碱对O2÷和.OH的清除作用;用硫代巴比妥酸(TBA)法测定VC-F e2+系统诱导大鼠肝匀浆及肝线粒体产生的脂质过氧化物丙二醛(M DA),研究青藤碱抗脂质过氧化的作用。结果青藤碱能清除.OH和O2÷,其EC50分别为1.35和0.136 m g/mL,且呈浓度依赖关系,青藤碱能抑制大鼠肝匀浆自氧化及VC-F e2+系统诱导引起的脂质过氧化。结论青藤碱具有清除氧自由基和抗脂质过氧化的作用,对肝线粒体也有保护作用。

葡萄籽提取物的体外抗脂质过氧化作用

以大鼠肝、脑组织匀浆为材料研究葡萄籽提取物 (GSE)的抗氧化作用。组织匀浆与GSE共浴后 ,比色法测定丙二醛 (MDA)生成量。组织匀浆与GSE共浴后 ,分别以自由基诱导剂CCl4、H2 O2 和铁离子 -抗坏血酸 (Fe2 + VC)激发脂质过氧化作用 ,以MDA产生和还原型谷胱甘肽 (GSH)耗竭作为脂质过氧化作用程度指标。结果表明 ,GSE可明显降低大鼠肝、脑组织自发性MDA的生成 ,减轻CCl4、H2 O2 、Fe2 + VC所致的肝脏脂质过氧化反应 ,减轻肝组织GSH耗竭。提示GSE具有良好的抗脂质过氧化作用。