共查询到19条相似文献,搜索用时 145 毫秒
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研究了升麻多糖的提取及其对羟基自由基的清除作用.采用热水浸提及醇沉法从升麻中提取多糖,通过比色法研究其清除羟基自由基的能力.升麻多糖清除能力与多糖浓度有明显的量效关系,清除50%羟基自由基所需要的多糖浓度为2.4mg/mL,结果表明升麻多糖具有良好的清除羟基自由基的能力. 相似文献
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采用二苯代苦味肼基自由基(DPPH)体系、羟基自由基体系、超氧阴离子自由基体系,对蕨菜醇提取物抗氧化特性进行研究,并同Vc、2,6-二叔丁基对甲酚(BHT)进行比较.结果表明:蕨菜醇提取物对这几种自由基均有不同程度清除作用,对DPPH自由基清除能力最强,当浓度为0.6mg/mL时,清除能力已超过BHT,当醇提物浓度为0.8mg/mL时,清除率已达83.6%,但一直小于Vc.醇提物浓度为15mg/mL时,对羟基自由基的清除率为82.4%,对超氧阴离子清除率为52.6%,在实验浓度范围内,抗氧化性小于Vc和BHT. 相似文献
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以总还原力、对DPPH自由基和超氧阴离子自由基清除作用、金属离子螯合能力为指标评价2%柳叶蜡梅叶挥发油体外抗氧化活性。结果表明:挥发油总还原力和对DPPH自由基、超氧阴离子自由基的清除作用的IC50值分别为182.58、89.66、53.42μL。挥发油总还原力和对DPPH自由基的清除能力低于1mg/mL维生素C,而对超氧阴离子自由基清除能力和金属离子的螯合能力明显高于1mg/mL维生素C和0.5mg/mLEDTA。柳叶蜡梅叶挥发油具有较好的体外抗氧化活性,值得进一步开发利用。 相似文献
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研究臭牡丹中黄酮类化合物的最佳提取工艺条件及其抗氧化活性.以提取时间、料液比、提取温度、乙醇体积分数为主要影响因素,以黄酮类化合物提取率为考察指标,确定最佳提取工艺条件,并通过对亚硝酸盐、超氧阴离子自由基、羟自由基的清除效果及对猪油的抗氧化研究其抗氧化活性.结果表明,臭牡丹中黄酮类化合物的最佳提取工艺条件为提取时间2.0h、料液比1∶40(g/mL)、提取温度70℃、乙醇体积分数70%的条件下提取效果最好,臭牡丹中黄酮类化合物在各抗氧化体系中均表现出较强的抗氧化活性,且其作用具有剂量效应关系,其抗氧化活性均强于维生素C. 相似文献
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三种中草药抗氧化性研究 总被引:1,自引:0,他引:1
微波辅助法提取3种中草药中黄酮类化合物,从还原能力、清除羟基自由基和抗油脂氧化方面,研究其抗氧化活性。结果表明:3种中草药中,总黄酮含量从高到低依次为:老鹤草(132.516mg/g)、豨莶草(78.4749mg/g)、白花蛇舌草(35.6519mg/g)。其提取物具有较好的还原能力,且对羟基自由基均有明显的清除作用,其清除效果随提取物浓度的增加而增强。三种中草药提取物也具有一定的抗油脂氧化能力,它们的抗氧化能力存在差异。实验结果为我们更加合理开发利用这些药用植物提供了很好的科学依据。 相似文献
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在酸性介质中,Fenton体系能够产生羟基自由基并可迅速氧化四乙基罗丹明B,通过光度法检测其在550nm处测定吸光度的变化,可以间接的测定羟基自由基.水果中含有许多抗氧化成分可以消除溶液中的羟基自由基,从而使溶液的吸光度下降程度减弱,据此建立了一种测定水果对羟基自由基清除的方法,实验对常见的4种水果的抗氧化活性进行了评价,以橙子的抗氧化活性最强. 相似文献
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The purpose of the study was to improve the extraction of polysaccharide from the leaves of Cercis chinensis Bunge using ultrasound, and compare the difference between boiling and ultrasound extraction in terms of polysaccharide content, monosaccharide compounds, and evaluate how the factors affected the bioactivity. The best conditions, according to the single factor experiments and the Box-Bohnken design (BBD), were an intensity of ultrasound of 180 W, duration of extraction of 40 min, proportion of water to material of 15:1 (g/g), and a higher polysaccharide yield of 20.02 ± 0.55 (mg/g) than in boiling extraction (16.09 ± 0.82 mg/g). The antioxidative experiment suggested the polysaccharide by ultrasound exhibited higher DPPH, hydroxyl radical scavenging capacities, and reducing power at 1.2–1.4 mg/mL, which was superior to the boiling polysaccharide. Further analysis showed that the ultrasonic purified polysaccharides like Gla, N-Glu, and GluA contained more total sugar and uronic acids than the boiling method did. This may indicate that the ultrasonic isolation of the polysaccharides increase the antioxidant activity of the polysaccharides. 相似文献
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刺梨是蔷薇科蔷薇属多年生落叶灌木,其果实富含多种生物活性物质,具有重要的药食用价值。采用近红外、紫外-可见、激发发射三维荧光光谱技术系统性表征刺梨鲜果提取物化学组成,探讨不同产地的301个批次刺梨果中总酚、总黄酮、总三萜类物质的含量与自由基清除能力、铁离子还原能力等抗氧化活性的分布特征。结果显示刺梨果中具有高含量的酚类、黄酮类、三萜类物质,分别为9.23~37.45,8.80~27.96和6.91~22.62 mg·g-1 FW(新鲜刺梨果的重量)。刺梨果具有较好的自由基清除活性和还原能力,对1,1-二苯基-2-三硝基苯肼(DPPH)清除率为14.39%~83.19%、2,2’-联氮基-双-(3-乙基-苯并噻唑啉-6-磺酸)二铵盐(ABTS)清除率18.50%~68.45%、对铁离子还原能力(FRAP)0.08~0.44 mmol·L-1 TE·g-1 FW。这些物质含量与活性指标数据均服从正态分布,表明实验用的多批次刺梨样本具有多样性、代表性、随机性,并且不同产地的样本提取物的活性成分含量及抗氧化活性没有显著的统计学差异性。提取物样本的紫外-可见、近红外、荧光光谱都具有明显的谱带特征,其光谱数据的主判别变量模型可有效鉴别八个不同产地的刺梨样本。研究表明多光谱技术能够表征提取物的物质组成,可对刺梨鲜果进行快速检测、品质差异判别与产地溯源,为刺梨质量评价、选种和资源开发提供参考。植物提取物的总酚、总黄酮等活性成分含量、抗氧化活性等指标不能准确反映样本的活性物质组成特征性,不能用于样本产地溯源分析。 相似文献
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A Ce(IV)-based reducing capacity (CERAC) assay was developed to measure the total antioxidant capacity (TAC) of foods, in
which Ce(IV) would selectively oxidize antioxidant compounds but not citric acid and reducing sugars which are not classified
as antioxidants. The method is based on the electron-transfer (ET) reaction between Ce(IV) ion and antioxidants in optimized
acidic sulphate medium (i.e., 0.3 M H2SO4 and 0.7 M Na2SO4) and subsequent determination of the produced Ce(III) ions by a fluorometric method. The fluorescent product, Ce(III), exhibited
strong fluorescence at 360 nm with an excitation wavelength of 256 nm, the fluorescence intensity being correlated to antioxidant
power of the original sample. The linear concentration range for most antioxidants was quite wide, e.g., 5.0 × 10−7–1.0 × 10−5 M for quercetin. The developed procedure was successfully applied to the TAC assay of antioxidant compounds such as trolox,
quercetin, gallic acid, ascorbic acid, catechin, naringin, naringenin, caffeic acid, ferulic acid, glutathione, and cysteine.
The proposed method was reproducible, additive in terms of TAC values of constituents of complex mixtures, and the trolox
equivalent antioxidant capacities (TEAC coefficients) of the tested antioxidant compounds gave good correlations with those
found by reference methods such as ABTS and CUPRAC. 相似文献
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用清除有机自由基DPPH法评价竹叶提取物抗氧化能力 总被引:18,自引:0,他引:18
通过对1,1-二苯基苦基苯肼(DPPH)溶液吸收光谱、DPPH溶液反应体系的研究,得出以下结论,分光光度法测定DPPH溶液反应体系的测定波长为518.4 nm,反应体系为4.00 mL 257.7 mg·L-1的DPPH溶液中加1 mL不同浓度的抗氧化剂,反应体系加入抗氧化剂后反应时间为40 min;用上述方法研究评价合成抗氧化剂叔丁基对苯二酚(TBHQ)和2,6-二叔丁基对甲酚(BHT)对DPPH自由基清除率和浓度的关系,以IC50值(清除率为50%时,抗氧化剂的浓度值)作为评价指标,测得合成抗氧化剂和效果最好竹叶提取物样品IC50值分别为,TBHQ(21.14 mg·L-1),BHT(42.09 mg·L-1),M40(108.40 mg·L-1),M40等竹叶提取物可以作为天然抗氧化剂进行开发。 相似文献
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用荧光探针法研究茶叶花粉黄酮对氧自由基致鼠红细胞膜氧化损伤的保护作用 总被引:2,自引:0,他引:2
应用1,6-二苯基-1,3,5-已三烯(DPH)为荧光探针,超氧阴离子自由基和羟基自由基致鼠红细胞膜氧化损伤为模型,研究了茶叶花粉黄酮对鼠红细胞膜氧化损伤的影响.结果表明,超氧阴离子自由基和羟基自由基均能引起鼠红细胞膜脂质过氧化反应,脂质过氧化产物丙二醛含量显著升高,膜脂流动性下降.将鼠红细胞膜预先用茶叶花粉黄酮处理后,膜脂的MDA含量明显下降,呈现剂量与效应关系,膜脂流动性显著提高,表明茶叶花粉黄酮对超氧阴离子自由基和羟基自由基引起的鼠红细胞膜的氧化损伤有保护作用. 相似文献
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This study was aimed at optimizing the astaxanthin extraction efficiency from shrimp shell (green tiger, Penaeus semisulcatus). Astaxanthin was extracted using selected nonpolar/polar solvents (petroleum ether, n-hexane, ethanol, acetone) individually and in ternary mixtures of petroleum ether, acetone, and water in ratios of 15:50:35, 50:45:5, and 15:75:10 for different times (2,4 and 6 h). The results showed that solvents with higher polarity were more suitable for the extraction of astaxanthin, and increasing the extraction time from 2 to 6 h improved the extraction yield. The conditions of extraction of astaxanthin with the desirable solvent were then optimized with the ultrasonic method using the Box-Behnken design [variables included: extraction temperature (25 to 45 °C), extraction time (5 to 15 min), and ultrasound amplitude (20 to 100%)]. Optimal extraction conditions were determined as the ultrasonic amplitude of 23.6%, extraction time of 13.9 min, and extraction temperature of 26.3 °C. Under this optimum condition, the amount of astaxanthin, ferric reducing antioxidant power, and free radical scavenging capacity of the extract were obtained as 51.5%, 1705 μmol of Fe2+/g, and 73.9%, respectively. Extraction and analysis of the extract at the optimum point were used to validate the results. 相似文献
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Paweł Berczyński Aleksandra Kładna Irena Kruk Teresa Piechowska Hassan Y. Aboul-Enein Oya Bozdağ-Dündar Meltem Ceylan-Unlusoy 《Journal of fluorescence》2013,23(6):1319-1327
The antioxidant properties of 11 new synthesized chromonyl-2,4-thiazolidinediones and chromonyl-2,4-imidazolidinediones (CBs) were investigated. The antioxidant activities and mechanisms of the CBs interaction with reactive oxygen species (ROS) were clarified using various in vitro antioxidant assay methods including superoxide anion radical ( $ \mathrm{O}\overline{{}_2^{\bullet }} $ ), hydroxyl radical (HO?), 1,1-diphenyl-2-picryl-hydrazyl free radical (DPPH?) scavenging activity and the iron (II)-ferrozine complex formation. The potassium superoxide/18-crown-6 ether dissolved in dimethylsulfoxide (DMSO) was applied as a source of superoxide anion radical. Hydroxyl radicals were produced in the Fenton-like reaction Fe(II)+H2O2. Chemiluminescence, spectrophotometry, and electron paramagnetic resonance (EPR) spectroscopy using 5,5-dimethyl-1-pyrroline-1-oxide (DMPO) as spin trap were applied as the measurement techniques. The CBs examined that exhibited good free radical scavenging activity also showed strong total antioxidant power capacity. Possible mechanisms of antioxidation are proposed to explain the differences in the experimental results between the chromone derivatives with imidazolidine-2,4-dione ring and those with thiazolidine-2,4-dione ring. In conclusion, some of the new CBs are promising to be applied as inhibitors of free radicals. 相似文献