DPPH、ABTS和FRAP微量法测定山奈酚的抗氧化能力

建立微量DPPH自由基和ABTS自由基清除法评价山奈酚对自由基清除能力的大小;建立微量总抗氧化能力法评价山奈酚的抗氧化活性强弱。山奈酚对DPPH和ABTS自由基的清除作用随浓度升高而增大,二者的IC_(50)分别为16.17和6.97μmol/L,其中山奈酚对ABTS自由基的清除能力与V_C相当。山奈酚的总抗氧化能力随浓度升高而增加,当浓度为500μmol/L时其总抗氧化能力为1.04±0.019 mmol/L。山奈酚具有一定的体外抗氧化能力,对DPPH和ABTS自由基均有较好的清除能力。     

野生蔬菜低温-超声破壁浸提物对ABTS自由基清除作用研究

本文为了研究7种常见野生蔬菜对ABTS自由基的清除作用,采用超声-低温破壁技术对7种野生蔬菜进行提取,运用ABTS法对提取物抗氧化活性进行测定比较,并对7种野生蔬菜提取物进行光谱扫描,优化测量条件。本文还根据7种野生蔬菜提取物对ABTS自由基清除曲线进行线性拟合,计算获得ABTS自由基清除的半数抑制浓度IC_(50)值。结果表明:所测野生蔬菜中抗氧化活性最强的为臭菜(IC_(50)值为0.465mg·mL~(-1)),最弱的为水生蔬菜水蕨菜(IC_(50)值为4.569mg·mL~(-1)),7种野生蔬菜抗氧化活性排序为:臭菜刺五加野芥兰菊花叶紫贝天葵冰草水蕨菜。本文采用超声-低温破壁处理可以最大程度提取和保留野生蔬菜的抗氧化活性,ABTS自由基清除试验也避免了样品溶液对DPPH自由基清除测量的光谱干扰,该方法简单、可靠,为研究野生蔬菜抗氧化活性提供方法和数据支撑。     

不同果皮颜色高粱抗氧化活性研究

通过对6种不同果皮颜色高粱的总酚含量测定,以及其清除DPPH自由基和ABTS自由基能力评价,分析高粱果皮颜色对其总酚含量的影响;以及高粱总酚含量与其清除DPPH自由基清除能力和ABTS自由基清除能力之间关系。结果表明,高粱果皮颜色深浅不是其总酚含量高低的可信指标。高粱总酚含量越高,其清除DPPH自由基和ABTS自由基能力越强,总酚含量与DPPH自由基清除能力之间呈线性正相关,相关系数为0.883 1;总酚含量与ABTS自由基清除能力之间也具有线性正相关特性,相关系数是0.915 1。     

不同条件下邻苯二酚及其衍生物捕获自由基性能研究

通过研究邻苯二酚及其衍生物清除ABTS+·自由基的实验,对其IC50进行比较,分析分子结构和环境因素影响邻苯二酚衍生物的抗氧化活性的规律.结果发现,咖啡酸和邻苯二酚的抗氧化性较强,冰醋酸环境清除能力基本不变,吡啶环境增强抗氧化性.     

石榴皮、金银花、牡丹复配物体外抗氧化作用评价

评价复配物体外抗氧化活性。采用DPPH和ABTS自由基清除法评价复配物的自由基清除能力;建立AAPH氧化损伤大鼠红细胞模型,研究复配物对红细胞溶血及对丙二醛(MDA)和抗氧化酶活力的影响。复配物对DPPH和ABTS自由基的清除作用与浓度呈正比,IC₅₀分别为0.065 mg/mL和0.13 mg/mL。复配物对红细胞溶血具有保护作用,并显著降低AAPH损伤4 h时MDA含量,提高谷胱甘肽过氧化物酶(GSH-Px)、超氧化物歧化酶(SOD)酶活。本实验的复配产物具有良好的体外抗氧化活性。     

不同配比的黄芪-当归药对体外抗氧化性实验研究

采用醇提法对黄芪、当归药对9种不同配伍比例进行提取,将提取液配置成含药材的6种浓度溶液,分别采用DPPH、ABTS和FRAP法检测9种不同配比黄芪-当归药对的抗氧化活性。研究发现当归∶黄芪=1∶0时对DPPH的清除效果最好,当归∶黄芪=3∶2时对ABTS+的清除能力最强,当归∶黄芪=1∶0对Fe3+的还原效果最好。实验结果表明当归比例高于黄芪比例的药对中抗氧化性越强,同时自由基的清除率随浓度的增加而增加。此研究为黄芪-当归配比用药提供了应用依据。     

一株太空培育螺旋藻诱变株的抗氧化能力研究

利用太空育种方法,培育得到新型的钝顶螺旋藻诱变株H11,乙醇提取多酚活性成分,用DPPH和ABTS法检测其抗氧化和自由基清除能力。实验结果表明,野生株和诱变株螺旋藻的总多酚得率分别为59.774 μg/g(干重)和87.881 μg/g(干重),野生株和诱变株螺旋藻提取物的DPPH自由基清除率IC_(50)分别为8.931和2.076 μg/mL,ABTS清除率IC_(50)分别为1.292和0.355 μg/mL;阳性对照物抗坏血酸、D-α-生育酚和Trolox的DPPH清除率IC_(50)分别为4.084,10.309和6.452 μg/mL,ABTS清除率IC_(50)分别为0.204,4.44和1.089 μg/mL。诱变株表现出优于野生株螺旋藻的DPPH和ABTS清除能力,且显著优于或接近抗坏血酸、D-α-生育酚和Trolox。     

三种云南产鲜花醇提液对ABTS自由基的清除作用

以3种常见食用花卉(玫瑰花、菊花、茉莉花)为原材料,经乙醇浸提得鲜花醇提液,考察了鲜花醇提液对ABTS自由基的清除作用。结果表明,浓度为2.5mg·mL~(-1)时,玫瑰花、菊花和茉莉花醇提液对ABTS自由基的清除率分别为80.61%、93.90%和83.71%,对ABTS自由基的半数抑制浓度(IC50值)分别为1.15mg·mL~(-1)、1.02mg·mL~(-1)和1.21mg·mL~(-1),其中菊花醇提液清除ABTS自由基的能力最强。食用玫瑰花、菊花、茉莉花醇提液均对ABTS自由基具有较强的清除作用,可作为天然抗氧化剂加以开发。为开发和利用云南鲜花资源作为天然高效食品抗氧化剂提供了理论依据。     

龙眼叶丙酮部位抗氧化活性研究

采用丙酮为溶剂,通过浸泡龙眼叶的方法得到龙眼叶丙酮提取物。以没食子酸为对照品测定该提取物的总酚含量,并采用ABTS体系评价眼叶丙酮提取物的抗氧化活性,探讨抗氧化活性和总酚含量之间的关系。龙眼叶丙酮提取物在较低药液浓度时即对ABTS自由基表现出一定的清除能力,且该清除能力与药液浓度呈正相关的关系。在最高药液浓度时,龙眼叶丙酮提取物对ABTS自由基的清除率达到74. 94%。此外,龙眼叶丙酮提取物具有良好的还原能力。     

7种云南可食用昆虫醇提液对ABTS+自由基清除作用

本文研究7种云南常见可食用昆虫对ABTS+自由基的清除作用.采用超声破壁技术提取制备7种可食用昆虫的乙醇提取物,研究加热对可食用昆虫ABTS+自由基清除能力的影响.通过线性拟合计算获得ABTS+自由基清除的半数抑制浓度IC50值.结果 表明:所测7种可食用昆虫中ABTS+自由基清除能力最强的为金蝉,最弱的为虾巴虫.7种...     

ABTS•+ scavenging activity of polypyrrole,polyaniline and poly(3,4‐ethylenedioxythiophene)

Although many methods are available for the evaluation of the antioxidant capacity of samples presented in the liquid state, typically food and beverages, to date only the 2,2′‐diphenyl‐1‐picrylhydrazyl (DPPH) assay has been applied to the measurement of the antioxidant capacity of solid samples such as active packaging materials. A modified 2,2′‐azino‐bis(3‐ethylbenzothiazoline‐6‐sulfonic acid) diammonium salt (ABTS) assay has been successfully developed for the measurement of the antioxidant capacity of conducting polymer powders. The ABTS^?+ radical scavenging activity of polypyrrole (PPy), polyaniline (PANI) and poly(3,4‐ethylenedioxythiophene) (PEDOT) powders was compared. The ranking order for greatest antioxidant capacity among the conducing polymer powders was PANI > PPy > PEDOT. The reduced forms of all the three conducting polymer samples were found to show greater radical scavenging activity than their as‐prepared partially oxidized forms. The modified ABTS assay is a simple, rapid and sensitive method for evaluating the antioxidant capacity of conducting polymer powders. The method is also suitable for composite antioxidant materials comprising a conducting polymer and a conventional packaging polymer. Copyright © 2010 Society of Chemical Industry     

拳参抗氧化活性研究

用清除二苯代苦味酰基（DPPH）自由基、2,2’-连氨-（3-乙基苯并噻唑啉-6-磺酸）二氨盐（ABTS）自由基和铁离子还原／抗氧化能力（FRAP）测定法对拳参体外总抗氧化活性进行评价．并与6-羟基-2,5,7,8-四甲基苯并二氢吡喃-2-羧酸（Trolox）及阳性对照二丁基羟基甲苯（BHT）比较。发现拳参有较好的体外抗氧化活性。甲醇提取物清除DPPH自由基（IC50=3．81μg／mL）的能力远远强于BHT的清除能力（IC50=18．71μg／mL）;清除ABTS自由基能力（IC50=7．65μg／mL）强于BHT（IC50=7．72μg／mL）的清除能力;还原Fe^3＋的能力（FRAP=2009．51±16．44μmol TE／g）最强,强于BHT（FRAP=1581．68±97．41μmol TE／g）。在3种提取物中,甲醇提取物具有最高的抗氧化能力,乙酸乙酯提取物次之。3种方法中,ABTS方法和FRAP方法相关性（R=0．984）最高。     

粘毛蓼的抗氧化活性

用清除二苯代苦味酰基(DPPH)自由基、清除[2,2′-连氨-(3-乙基苯并噻唑啉-6-磺酸)二氨盐](ABTS)自由基和铁离子还原/抗氧化能力(FRAP)测定法,对粘毛蓼体外总抗氧化活性进行了评价,结果与6-羟基-2,5,7,8-四甲基苯并二氢吡喃-2-羧酸(Trolox)及阳性对照丁基羟基茴香醚(BHA)、二丁基羟基甲苯(BHT)比较发现,粘毛蓼提取物有很好的体外抗氧化活性。乙酸乙酯提取物清除DPPH自由基(IC50=7.89 mg/L)的能力比BHT清除能力(IC50=18.71 mg/L)强,比BHA(IC50=3.20 mg/L)清除能力略弱;清除ABTS自由基能力(IC50=6.67 mg/L)比BHT(IC50=7.72 mg/L)清除能力强,比BHA(IC50=1.88 mg/L)清除能力弱;还原Fe3+的能力〔FRAP=(1362.55±47.22)μmol TE/g〕比BHT〔FRAP=(1581.68±97.41)μmol TE/g〕略低。在3种提取物中,乙酸乙酯提取物具有最高的抗氧化能力,甲醇提取物次之。3种方法中,DPPH方法和ABTS方法相关性最高(R=0.993)。     

核桃仁抗氧化活性研究

采用清除二苯代苦味肼基(DPPH)自由基、清除[2,2′-连氨-(3-乙基苯并噻唑啉-6-磺酸)二氨盐](ABTS)自由基及铁离子还原/抗氧化能力(FRAP)测定法,对核桃仁提取物进行抗氧化活性评价,并与阳性对照没食子酸丙酯(PG)、丁基羟基茴香醚(BHA)和二丁基羟基甲苯(BHT)进行比较。在核桃仁提取物中,乙酸乙酯提取物清除DPPH和ABTS自由基的能力(IC50值分别为1.58 mg/L和1.69 mg/L)强于BHA(IC50值分别为3.43 mg/L和1.72 mg/L)和BHT(IC50值分别为18.79 mg/L和6.04 mg/L),弱于PG(IC50值分别为0.86 mg/L和0.66 mg/L);乙酸乙酯提取物还原Fe3+的能力最强〔FRAP值为(13212.99±55.35)μmol TE/g〕,强于PG〔FRAP值为(10617.75±138.38)μmol TE/g〕、BHA〔FRAP值为(7383.10±121.08)μmol TE/g〕和BHT〔FRAP值为(1748.49±3.46)μmol TE/g〕;核桃仁正丁醇提取物清除DPPH和ABTS自由基的能力(IC50值分别为4.94和1.90 mg/L)以及还原Fe3+的能力〔FRAP值为(2299.99±27.68)μmol TE/g〕强于BHT。结果表明,核桃仁乙酸乙酯和正丁醇提取物都具有很好的抗氧化活性,且乙酸乙酯提取物活性强于正丁醇提取物。     

开封产3种白色菊花提取物的抗氧化活性

采用清除二苯代苦味肼基(DPPH)自由基、清除[2,2′-连氨-(3-乙基苯并噻唑啉-6-磺酸)二氨盐](ABTS)自由基及铁离子还原/抗氧化能力(FRAP)测定法,对开封产的3种白色菊花(兼六香白、国华万胜及白玉带)不同溶剂提取物的体外抗氧化活性进行了评价,将所测定结果与水溶性维生素E(6-hydroxy-2,5,7,8-tetramethyl-chroman-2-carboxylic acid,Trolox)及阳性对照二丁基羟基甲苯(BHT)进行了比较。结果表明,3种菊花的不同溶剂提取物抗氧化活性不同。同一种菊花的甲醇提取物具有很好清除DPPH自由基和还原铁离子的能力,而石油醚提取物几乎无活性。菊花的3个品种中,兼六香白和国华万胜的抗氧化活性较好,其活性远远超过白玉带的抗氧化活性。9个提取物中,兼六香白的甲醇提取物总的抗氧化活性最好。它对DPPH自由基的清除能力(IC50值为20.49 mg/L)比BHT(IC50值为18.92 mg/L)作用略低;其还原Fe3+的能力(FRAP值为731.73±1.77μmol TE/g)比BHT(1 581.68±97.41μmol TE/g)作用低1/2。3种方法测定结果基本一致,其中以DPPH法和FRAP法相关性最好(R=0.982 0)。     

Radical scavenging activity of canola hull phenolics

Possible use of canola hulls as a source of natural anti-oxidants was explored. Cyclone canola hulls were extracted with methanol (30 to 80%, vol/vol) and acetone (30 to 80%, vol/vol). The free radical-scavenging activity of phenolic extracts so prepared was evaluated using the 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonate) (ABTS) radical ion (ABTS^o−), 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, and chemiluminescence assays. The total content of phenolics in prepared extracts from canola hulls ranged from 15 to 136 mg sinapic acid equivalents per gram of extract. Higher levels of condensed tannins were detected in the acetone extracts than in the corresponding methanolic counterparts. Seventy and 80% (vol/vol) acetone extracts displayed markedly stronger antioxidant activity than any of the other extracts investigated. Statistically significant linear correlations were found between TEAC (Trolox equivalent antioxidant capacity) values (expressed in mM of Trolox equivalents per gram of extract) and total pehnolics, TEAC and total condensed tannins (i.e., determined using the modified vanillin and pronthocyanidin assays), as well as TEAC and protein precipitation activity of phenolic extracts (i.e., measured using the dye-labeled assay). The antioxidant activities of extracts as determined by the ABTS^o− radical ion assay correlated highly with those of the chemiluminescence and DPPH radical assays.     

Antioxidant activities of extract and fractions from receptaculum nelumbinis and related flavonol glycosides

The antioxidant activities of ethanolic crude extract (ECE) and its four different solvent sub-fractions (namely, petroleum ether fraction (PEF), ethyl acetate fraction (EAF), n-butanol fraction (BF) and the aqueous fraction (AF) from the receptacles of Nelumbo nucifera Gaertn. (Receptaculum Nelumbinis) were investigated using two in vitro antioxidant assays. BF showed the highest total phenolic content (607.6 mg/g gallic acid equivalents), total flavonoid content (862.7 mg/g rutin equivalents) and total proanthocyanidin content (331.0 mg/g catechin equivalents), accompanied with the highest antioxidant activity compared to other fractions through 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azino-bis-(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) radical scavenging assays. Five flavonol glycosides, namely hyperoside (1), isoquercitrin (2), quercetin-3-O-β-d-glucuronide (3), isorhamnetin-3-O-β-d-galactoside (4) and syringetin-3-O-β-d-glucoside (5) were isolated from the Receptaculum Nelumbinis. Compounds 2-5 were isolated for the first time from the Receptaculum Nelumbinis. The five isolated flavone glycosides, particularly compounds 1-3, demonstrated significant DPPH and ABTS radical scavenging activity, with IC(50) values of 8.9 ± 0.2, 5.2 ± 0.2, 7.5 ± 0.1 for DPPH and 114.2 ± 1.7, 112.8 ± 0.8, 172.5 ± 0.7 μg/mL for ABTS, respectively. These results suggest that Receptaculum Nelumbinis has strong antioxidant potential and may be potentially used as a safe and inexpensive bioactive source of natural antioxidants.