纯化的绞股蓝皂苷的抗氧化活性研究

目的:比较经不同纯化条件纯化的绞股蓝皂苷样品的体外抗氧化能力,方法:通过清除DPPH自由基,羟自由基,抑制脂质过氧化的能力,还原力来检测样品的抗氧化能力。结果:对DPPH自由基清除率最高的是总皂苷A,达86.08%;对.OH的清除率最高的总皂苷A’,为53.49%;对脂质过氧化的抑制率最高的是总皂苷A,为54.08%,还原力大小排序为总皂苷A>总皂苷A’>总皂苷B。结论:总皂苷A的抗氧化能力最强。     

花脸香蘑菌丝体提取物的体外抗氧化活性

分别测定花脸香蘑Lepista sordida发酵菌丝体不同浓度乙醇溶剂提取液在4种抗氧化模型中的抗氧化作用。结果表明, 各种菌丝体提取液对二苯基苦味酰基苯肼自由基(·DPPH)和羟自由基(·OH)均有显著的清除作用, 其清除作用随着乙醇溶剂浓度的提高而降低: 在3 g/L菌丝生药浓度时, 去离子水提取物对DPPH自由基和羟自由基的清除率分别为90.55%和81.9%; 在6 g/L菌丝生药浓度时, 50%乙醇和70%乙醇提取物对DPPH自由基的清除率分别为53.7%和45.2%, 对羟自由基的清除率分别为79.4%和78.4%。各菌丝提取物也具有极强的抗脂质过氧化能力, 在5 g/L菌丝生药浓度64 h内, 水提物、50%乙醇和70%乙醇提取物对亚油酸过氧化物的抑制率分别为100%、96%和89.2%。在一定浓度下, 各提取液对邻苯三酚自氧化也均有抑制作用。     

费菜不同组织总黄酮抗氧化与抑菌活性的研究

本文采用费菜不同组织(嫩叶、老叶、茎、花)中总黄酮进行体外抗氧化能力及抑菌作用的研究。对Fe~(3+)还原活性、清除DPPH·、·OH进行体外抗氧化活性试验,并采用两倍稀释法探讨费菜不同组织抑制大肠杆菌、金黄色葡萄球菌、枯草芽孢杆菌的活性。结果表明,费菜不同组织总黄酮的Fe~(3+)还原活性、DPPH·清除率、·OH清除率均显著高于L-抗坏血酸。其中,Fe~(3+)还原活性可达到810μmol TE/mL以上;对DPPH·以及·OH清除率的IC_(50)值最低分别为0. 8μg/mL(茎)和14μg/mL(花)。费菜各组织总黄酮均有一定的抑菌作用,对金黄色葡萄球菌的抑制效果较好;对于大肠杆菌,茎和嫩叶中的总黄酮的抑制效果明显比老叶和花强;而四个组织总黄酮对枯草芽孢杆菌的抑制作用相当,其中老叶总黄酮的抑制效果略好。该试验结果为费菜不同组织总黄酮的应用提供理论基础。     

金银花尺蠖幼虫粪便乙醇提取物体外抗氧化活性

自由基过量累积会影响生物体正常机能,筛选具有自由基清除功能的昆虫代谢产物对于开发虫茶至关重要。为了解金银花尺蠖幼虫粪便提取物的抗氧化活性,在室内测定了金银花尺蠖幼虫粪便乙醇提取物的体外抗氧化活性。结果表明,金银花尺蠖幼虫粪便乙醇提取物具有一定的体外抗氧化活性:对二苯代苦味酰自由基(DPPH)、羟基自由基(·OH)、超氧阴离子自由基(O-·2)、ABTS+·自由基均具有一定的清除能力,在0.05mg/m L时的清除率分别为37.78%、25.31%、21.41%和35.82%;随着提取物浓度的增大,对自由基的清除率逐渐增加,当浓度上升到0.65 mg/m L时的清除率分别为95.52%、69.07%、63.27%和72.46%,分别增加了57.74%、43.76%、41.86%和36.64%,差异达显著水平;对卵黄脂蛋白脂质过氧化也具有一定的抑制作用,在0.05 mg/m L时的抑制率为26.78%,随着提取物浓度的增大,对脂质过氧化的抑制率也逐渐增加,当浓度上升到0.65 mg/m L时的抑制率为50.63%,增加了23.85%,差异达显著水平。在0.05~0.65 mg/m L的浓度范围内,对自由基的清除率、对脂质过氧化的抑制率与浓度之间呈显著的线性关系。综上,金银花尺蠖幼虫粪便提取物具有开发为虫茶的潜力。     

南瓜醇提物的体外抗氧化活性(英文)

采用化学体系模拟法体外测定南瓜醇提物((pumpkin ethanol extract,PEE)对1,1-二苯基-2-苦苯肼自由基(DPPH·)、超氧阴离子自由基(O2)和羟自由基(·OH)的清除能力,总还原力,对β-胡萝卜素/亚油酸自氧化体系的总抗氧化能力以及脂质过氧化的抑制能力.结果显示PEE对DPPH·、02-和·OH均有较强的清除能力,IC50值分别为18.8 mg/mL、29.0 ms/mL和44.9μg/mL,有显著的还原力和总抗氧化力,对脂质过氧化有一定的抑制作用.PEE的体外抗氧化活性均有良好的量效关系.上述结果为南瓜作为抗氧化的保健食品或功能食品开发利用提供了依据.     

灵芝孢子副产物体外抗氧化活性的研究

利用有机溶剂萃取法获得灵芝孢子副产物五个不同极性部位,以总抗氧化能力(T-AOC)及羟自由基(·OH)和2,2-二(4-叔辛基苯基)-1-苦肼基自由基(DPPH·)的清除能力为评价指标筛选最优抗氧化活性部位,并对其进行抗脂质过氧化研究,结果显示:不同极性部位均能清除上述自由基,其中乙酸乙酯相活性最强。进一步研究发现,乙酸乙酯相能够显著抑制β-胡萝卜素/亚油酸体系,同时对小鼠肝脏自氧化及H2O2诱导的肝脂质过氧化和红细胞过氧化溶血均有较好保护作用。实验表明:灵芝孢子副产物不同极性部位提取物均具一定程度的抗氧化活性,其中乙酸乙酯相活性最强。     

灵芝孢子副产物体外抗氧化活性的研究北大核心CSCD

利用有机溶剂萃取法获得灵芝孢子副产物五个不同极性部位,以总抗氧化能力(T-AOC)及羟自由基(·OH)和2,2-二(4-叔辛基苯基)-1-苦肼基自由基(DPPH·)的清除能力为评价指标筛选最优抗氧化活性部位,并对其进行抗脂质过氧化研究,结果显示:不同极性部位均能清除上述自由基,其中乙酸乙酯相活性最强。进一步研究发现,乙酸乙酯相能够显著抑制β-胡萝卜素/亚油酸体系,同时对小鼠肝脏自氧化及H2O2诱导的肝脂质过氧化和红细胞过氧化溶血均有较好保护作用。实验表明:灵芝孢子副产物不同极性部位提取物均具一定程度的抗氧化活性,其中乙酸乙酯相活性最强。     

蛹虫草无性型菌丝体提取液体外抗氧化活性研究

分别测定了蛹虫草无性型菌丝体不同溶剂提取液在不同抗氧化模型中的抗氧化作用。结果表明,各种提取液对二苯基苦味酰基苯肼自由基(·DPPH)和羟自由基(·OH)均有显著的清除作用:在50mg/mL时,去离子水、70%乙醇和70%丙酮提取物对DPPH自由基的清除率分别为89.2%、83.6%和75.9%;70%乙醇提取物在30mg/mL时对·OH自由基的清除率达到100%;在50mg/mL时70%丙酮和去离子水提取物的·OH自由基清除率分别为95.6%和89.6%。在一定浓度下,各提取液对邻苯三酚自氧化也均有抑制作用;不同溶剂提取物的还原能力强弱为:70%乙醇>去离子水>70%丙酮。各种提取物的抗氧化组分不同,提取物浓度与抗氧化性成正相关。     

球孢白僵菌不同菌株清除自由基活性评价

选择不同来源的12株球孢白僵菌,分别测定菌丝体2种溶剂提取物在不同抗氧化模型中的抗氧化作用。结果表明,不同溶剂提取物对二苯基苦味酰基苯肼自由基(DPPH)和羟自由基(.OH)均有清除作用,但是清除自由基的活性不同,乙酸乙酯提取物对.OH的清除作用最为显著,活性较高,最高清除率达到71.54%。甲醇提取物活性均较低,30 min时甲醇提取物对DPPH和.OH清除率最高分别为36%和38.96%,12株白僵菌间的清除自由基活性有较大的差异。     

麦草粉的抗氧化作用研究

测定了大麦和黑麦草嫩叶汁粉的小鼠肝脂质过氧化作用和抗油脂过氧化作用。结果表明,麦草汁粉具有显著的抗小鼠肝脂质过氧化作用,抑制率分别达38．23％（大麦嫩叶汁粉）和69．16％（黑麦草嫩叶汁粉）;对油脂的过氧化也具有一定的抑制作用。麦草汁粉的抗氧化作用主要与其所含酚性物质有关。     

Antioxidant properties of alpha-crystallin

-Crystallin is a major chaperone lens protein to which has been ascribed antioxidant functions. In the present work we have evaluated the antioxidant and free radical scavenging properties of bovine -crystallin in a series of in vitro models: zimosan-induced, luminol-enhanced chemiluminescence response of polymorphonuclear leukocytes, the autoxidation of brain homogenate, bleaching of 2,2-azinobis(3-ethylbenzothiazoline-6-sulfonic acid)-derived radical cations, trapping of peroxyl radicals, and reactivity toward hypochloric acid. In all these systems, the reactivity of -crystallin is higher than or similar to that of bovine serum albumin. It is concluded that, given the high concentrations of -crystallin in the lenses, its capacity to interact with free radicals and to remove hypochlorous acid could contribute to the maintenance of the lens functionality.     

精氨酸抗氧化作用机制

精氨酸是一种功能性氨基酸,在机体生理功能、新陈代谢和营养等方面发挥着重要作用。精氨酸具有抗氧化能力。目前的体外研究表明精氨酸具有较强的清除DPPH自由基、ABTS自由基、超氧自由基能力以及一定的还原力。作为一种带电子的碱性氨基酸,精氨酸可能通过胍基基团向自由基提供电子并与其作用,终止自由基链式反应,从而显示出还原能力与体外抗氧化能力。体内实验则表明精氨酸能有效地提高机体总抗氧化能力,降低体内自由基含量,抑制ROS生成与积累,促进谷胱甘肽(GSH)合成与积累,增强内源性抗氧化酶(CAT、SOD、GPx等)活性,抑制氧化应激的产生。精氨酸能够通过精氨酸——一氧化氮途径、GSH途径、Nrf2信号通路途径及其他途径发挥体内抗氧化作用。本文主要综述了目前精氨酸体外与体内抗氧化功能及其相关作用机制的研究进展,为精氨酸的实际应用提供理论指导意义。     

Antioxidant functions of carotenoids

Carotenoid pigments, including hydrocarbons such as β-carotene or xanthophylls such as lutein and zeaxanthin, are very widely distributed in nature, where they play an important role in protecting cells and organisms against the harmful effects of light, air, and sensitizer pigments. This process has been demonstrated in bacteria, algae, plants, animals, and even in humans in the light-sensitive disease, erythropoietic protoporphyria. The primary mechanism of action of this phenomenon appears to be the ability of carotenoids to quench excited sensitizer molecules as well as quench ¹O₂.

In addition to this protection, and potentially of even greater biological importance, is the fact that carotenoids can also serve as antioxidants under conditions other than photosensitization. This review presents the data available indicating the extent of this important function. Antioxidant action can be documented in both enzymic and nonenzymic systems, and has been reported in subcellular, cellular, and animal studies. In fact, the many reports indicating that carotenoids may possess some anticarcinogenic properties may well be related to their ability to interact with and quench various radical species that can be generated within cells.     

Antioxidant activity of carotenoids

Carotenoids are pigments which play a major role in the protection of plants against photooxidative processes. They are efficient antioxidants scavenging singlet molecular oxygen and peroxyl radicals. In the human organism, carotenoids are part of the antioxidant defense system. They interact synergistically with other antioxidants; mixtures of carotenoids are more effective than single compounds. According to their structure most carotenoids exhibit absorption maxima at around 450 nm. Filtering of blue light has been proposed as a mechanism protecting the macula lutea against photooxidative damage. There is increasing evidence from human studies that carotenoids protect the skin against photooxidative damage.     

Antioxidant properties of steroids

To determine the relative ranking of antioxidative potential of various steroids the effect of 14 steroid compounds on the fluorescence of phycoerythrin was monitored over time following the addition of a peroxy radical generator 2,2′-azobis (2-amidino-propane) dihydrochloride. The rate of decay of fluorescence in the presence of a 200 nM of 17β-estradiol, 17-estradiol and estriol expressed as percentages of the rate of decay in the absence of these compounds (control curve), were 74.1±6.3, 84.0±5.42 and 64.2±2.53%, respectively (P<0.005). Cortisone and corticosterone appeared to have very mild proxidant properties. Other steroids tested such as esterone, testosterone, progesterone, androstenedione, dehydroepiandrosterone, cortisol, tetrahydrocortisone, deoxycorticosterone and aldosterone had no significant antioxident properties. It is concluded that estrogens especially estriol and 17β-estradiol are naturally occurring antioxidants.     

Antioxidant Activity of Diethyldithiocarbamate

Diethyldithiocarbamate (DDC), a potent copper chelating agent, has long been used for the treatment of oxygen toxicity to the central nervous system, as an immunomodulator to treat cancer, and in HIV-infected patients. We evaluated the antioxidant properties of DDC, including its scavenging of reactive oxygen species, its reducing properties, its iron-chelating properties, and its protective effects on oxidant-induced damage to brain tissue, protein, human LDL, and DNA. It is found that DDC is a powerful reductant and antioxidant since it scavenges hypochlorous acid, hydroxyl radical and peroxynitrite; it chelates, then oxidizes ferrous ions; it blocks the generation of hydroxyl radicals and inhibits oxidative damage to deoxyribose, protein, DNA, and human LDL. These findings may provide an explanation for the apparent beneficial effects of DDC against oxidative stress-related diseases that have been observed in experimental and clinical studies.     

微生物源性抗氧化剂对小鼠抗氧化性能及免疫功能的影响

旨在探究不同剂量的微生物源性抗氧化剂对小鼠抗氧化性能及免疫功能的影响。将60只28日龄雌性昆明小鼠随机分为4组,每组15只。试验组分别以0.5 g/kg bw*d(低)、1.0 g/kg bw*d(中)、1.5 g/kg bw*d(高)的剂量灌喂微生物源性抗氧化剂,每天1次,连续30 d,灌胃容量为0.2 mL/10 g bw*d,对照组灌喂等容量的蒸馏水。30 d后,测定微生物源性抗氧化剂对小鼠抗氧化性能及免疫功能的影响。结果表明,1.0 g/kg bw*d的微生物源性抗氧化剂可以极显著地提高血清中GSH-Px的活力(P<0.01),显著提高T-SOD活力(P<0.05),降低MDA的含量(P>0.05)。而1.5g/kg bw*d的微生物源性抗氧化剂可以极显著地提高血清中IgA的含量(P<0.01)和IL-2水平,以及ConA刺激的脾淋巴细胞转化率(P<0.01),促进脾脏和胸腺的发育(P>0.05)。提示1.0g/kg bw*d的微生物源性抗氧化剂可以显著增强小鼠的抗氧化能力,1.5 g/kg bw*d的微生物源性抗氧化剂可以增强免疫功能。     

Antioxidant defences of the apoplast

Summary The apoplast of barley and oat leaves contained superoxide dismutase (SOD), catalase, ascorbate peroxidase, dehydroascorbate reductase, monodehydroascorbate reductase, and glutathione reductase activities. The activities of these enzymes in the apoplastic extracts were greatly modified 24 h after inoculation with the biotrophic fungal pathogenBlumeria graminis. The quantum efficiency of photosystem II, which is related to photosynthetic electron transport flux, was comparable in inoculated and healthy leaves during this period. Apoplastic soluble acid invertase activity was also modified in inoculated leaves. Inoculation-dependent increases in apoplastic SOD activity were observed in all lines. Major bands of SOD activity, observed in apoplastic protein extracts by activity staining of gels following isoelectric focusing, were similar to those observed in whole leaves but two additional minor bands were found in the apoplastic fraction. The apoplastic extracts contained substantial amounts of dehydroascorbate (DHA) but little or no glutathione (GSH). Biotic stress decreased apoplastic ascorbate and DHA but increased apoplastic GSH in resistant lines. The antioxidant cycle enzymes may function to remove apoplastic H₂O₂ with ascorbate and GSH derived from the cytoplasm. DHA and oxidized glutathione may be reduced in the apoplast or returned to the cytosol for rereduction.Abbreviations AA reduced ascorbate - APX ascorbate peroxidase - DHA dehydroascorbate (oxidised ascorbate) - DHAR dehydroascorbate reductase - G6PDH glucose-6-phosphate dehydrogenase - GSH reduced glutathione - GSSG glutathione disulphide - GR glutathione reductase - MDHA monodehydroascorbate - MDHAR monodehydroascorbate reductase - SOD superoxide dismutase     

Antioxidant properties of ganglioside micelles

Antioxidant activity of gangliosides GM1 and GT1b in the Fenton type of reaction was investigated by EPR spectroscopy using DMPO as a spin trap. Hydroxyl radical spin adduct signal intensity was significantly reduced in the presence of gangliosides at their micellar concentrations. Mean micellar hydrodynamic diameter was not changed, whereas significant changes in negative Zeta potential values were observed as evidenced by Zetasizer Nano ZS. This study showed that the primary mode of ganglioside action was not due to direct scavenging of OH·, but rather to the inhibition of hydroxyl radical formation. This phenomenon is related to the ability of ganglioside micelles to bind oppositely charged ferrous ions, thus reducing their concentration and consequently inhibiting OH· formation.