马齿苋多糖清除羟自由基作用的研究

目的检测马齿苋多糖清除羟自由基作用。方法利用热水提取乙醇沉淀法制得马齿苋多糖,用分光光度法检测马齿苋多糖对1,1-二苯基-2-苦肼基自由基（DPPH？）,羟自由基（OH？）和超氧阴离子自由基（O2-1）的清除能力。结果与结论马齿苋多糖溶液对DPPH？自由基、OH？和O2-1均具有良好的清除作用,作用随剂量增加而增强。     

锡兰海木耳多糖的提取、理化性质及抗氧化活性研究

目的 从红藻锡兰海木耳（Sarcodia ceylonensis）中提取多糖,对其化学组成和理化性质进行分析,并进行体外抗氧化活性评价。方法 依次通过冷水、热水（85 ℃）和4% NaOH溶液提取海木耳多糖;通过化学方法测定其总糖和硫酸根含量;利用PMP柱前衍生高效液相色谱法、高效凝胶渗透色谱法、红外光谱等方法对其单糖组成、相对分子质量和结构特征进行分析;通过测定其对超氧阴离子自由基（O2-）、羟自由基（?OH）和DPPH自由基的清除作用、对Fe2+的螯合能力和还原能力评价其体外抗氧化活性。结果 3种多糖SCW（冷水提取多糖）、SCH（热水提取多糖）和SCA（碱液提取多糖）的相对分子质量分别为6.65 × 105、2.55 × 105和1.35 × 105;单糖组成相似,均含有半乳糖、岩藻糖、甘露糖和葡萄糖醛酸,其中3,6-内醚-半乳糖和半乳糖含量均达到20%以上;硫酸根含量较高,分别为12.74%、13.46%和19.76%;3种多糖对O2-、?OH和DPPH自由基均有显著的清除作用,对Fe2+均表现出显著的螯合能力,其中SCA抗氧化活性最强。结论 从锡兰海木耳中提取得到3种硫酸多糖,均具有显著的体外抗氧化活性,为其将来作为食品和化妆品添加剂提供了有用参考。     

分光光度法检测马齿苋多糖的抗氧化活性

目的检测马齿苋多糖抗氧化活性。方法利用热水提取乙醇沉淀法制得马齿苋多糖,用分光光度法检测马齿苋多糖对1,1-二苯基-2-苦味酰基自由基（DPPH.）,羟自由基（OH.）和超氧阴离子自由基（O2-1）的清除能力。结果马齿苋多糖溶液对DPPH.自由基、OH.和O2-1均具有良好的清除作用,作用随剂量增加而增强。结论马齿苋多糖具有很大的开发利用前景。     

茉莉花挥发油清除自由基活性的研究

目的：从清除1,1－二苯基－2－苦苯肼自由基（DPPH?）、羟自由基（? OH）、超氧阴离子自由基（O2?－）3个方面,研究茉莉花挥发油清除自由基活性。方法采用水蒸气蒸馏法提取茉莉花挥发油,从其清除DPPH?、? OH和O2?－能力3个方面进行考察,并以常用抗氧化剂L－抗坏血酸为对照作比较,通过计算半数抑制浓度（ IC50）评价茉莉花挥发油清除,在供试质量浓度范围内,呈一定量效关系,其 IC50分别为153．548μg?mL －1、56．481μg? mL －1和133．586μg? mL －1。结论茉莉花挥发油具有良好的清除自由基活性,是一种新型天然抗氧化物质来源。     

鱿鱼墨黑色素的自由基清除活性研究

目的比较鱿鱼墨黑色素和黑色素铁的自由基清除活性。方法采用高速离心法从北太平洋鱿鱼（Ommastrephes bartrami）墨中提取黑色素，并通过黑色素与FeCl3螯合制备了Fe（Ⅲ）含量为5．6％（W／W）的黑色素铁。采用鲁米诺发光系统测定了黑色素和黑色素铁对羟自由基（·OH）与超氧阴离子自由基（O2^·-）清除活性。结果鱿鱼墨黑色素清除超氧阴离子自由基和羟自由基的IC50值分别为0．2mg·mL^-1和0．015mg·mL^-1，远低于肌肽的0．53mg·mL^-1和0．1mg·mL^-1，而黑色素铁清除超氧阴离子自由基和羟自由基的IC50值分别为0．58mg·mL^-1和0．83mg·mL^-1。结论鱿鱼墨黑色素是一种活性较高的天然自由基清除剂，而黑色素铁的自由基清除活性较黑色素低。     

烟酰化孔石莼多糖的制备及抗氧化活性研究

摘要：目的 探究烟酰化孔石莼多糖NU的最佳制备工艺,并测定其体外抗氧化活性。方法 分别以甲酰胺（FA）、N,N-二甲基甲酰胺(DMF)、二甲基亚砜(DMSO)为溶剂,烟酰氯盐酸盐为酰化剂,以氮元素含量为指标采用单因素法确定最佳溶剂,再采用正交设计法,考察孔石莼多糖U与酰化剂的质量比、U的质量浓度、反应时间、反应温度对反应的影响。经氮元素分析、红外光谱(IR)、核磁共振碳谱(13C-NMR),推测烟酰化衍生物(NU)的化学结构。并研究NU对超氧阴离子自由基（O2??）、羟自由基（?OH）的清除作用以及还原能力、金属螯合能力。结果 烟酰化反应最佳条件：多糖与烟酰化试剂的质量比为1:2,多糖的质量浓度15 g?L?1,反应时间4 h、反应温度为125 ℃。NU的结构已初步确定。对羟自由基（?OH）的清除作用及其还原能力、金属螯合能力,NU与U相比表现出更优的活性;但对超氧阴离子自由基（O2?）的清除作用二者无明显差异。结论 通过确定的实验方案,烟酰化反应是成功的,烟酰化孔石莼多糖NU的抗氧化活性有显著增强。     

林蛙皮的抗氧化性研究

目的 研究林蛙皮的抗氧化性.方法 以1,1-二苯基苦基苯肼自由基(DPPH·)清除能力作为考察指标,通过正交实验确定林蛙皮抗氧化物质的最佳提取方案,并进一步测定林蛙皮提取液的清除羟自由基、超氧阴离子的能力,综合分析林蛙皮的抗氧化能力.结果 林蛙皮抗氧化物质提取的最优方案为:采用冷冻干燥的方式,用蒸馏水在50 ℃下提取30 min,其DPPH·清除率达79.12%,且DPPH·的清除能力随浓度增加而增强;林蛙皮水提物也表现出较强的·OH清除能力,但对O2-.的清除能力较弱.结论 林蛙皮水提液对DPPH·和·OH具有很好的抗氧化性,但对O2-.作用不明显.     

黄山杜鹃总黄酮的体外抗氧化活性研究

目的 研究黄山杜鹃总黄酮的抗氧化活性.方法 采用体外实验研究黄山杜鹃总黄酮的还原力、金属螯合性及对1,1-二苯基苦基苯肼自由基(DPPH·)、超氧阴离子自由基(O2-·)、亚硝酸钠的清除能力.结果 黄山杜鹃总黄酮提取液的浓度为505 mg· L-1,总黄酮提取液有很好的还原力和金属离子的螯合能力;总黄酮对DPPH·、O2-·和亚硝酸钠有清除作用,且存在量效关系.结论 黄山杜鹃总黄酮在体外具有抗氧化活性.     

桂花不同溶剂提取物对氧自由基清除作用的ESR研究

目的研究桂花不同提取物对氧自由基的清除作用。方法利用不同极性溶剂（水、石油醚、乙酸乙酯、正丁醇）浸提桂花粉后得到不同极性的提取物。通过电子自旋共振（ESR）和自旋捕集技术,以1,1-二苯基-2-三硝基苯肼自由基（DPPH）及核黄素光照条件下产生超氧阴离子O2^-自由基体系,检测桂花中各组分清除DPPH自由基及O2^-的能力。结果以维生素C为对照,桂花水提取物、石油醚提取物、乙酸乙酯提取物、正丁醇提取物及维生素C清除DPPH自由基能力IC50分别为59.63,53.93,28.33,38.89,40.93μg·mL^-1;各提取物及维生素C对超氧阴离子O2-自由基清除能力IC50分别为63.37,55.47,30.20,48.36,41.52μg·mL^-1。其中各提取物的乙酸乙酯提取物的DPPH及O2^-清除率最大。结论通过比较各组分对DPPH自由基及超氧阴离子自由基的清除能力,了解桂花中抗氧化成分在各相中的分布情况,并据此进行有目的的分离桂花中的抗氧化成分。     

广西茉莉花叶不同极性部位提取物的抗氧化活性

目的测定茉莉花叶不同极性部位提取物的抗氧化活性。方法对茉莉花叶提取物用石油醚、乙酸乙酯、正丁醇进行萃取得到石油醚部位、乙酸乙酯部位、正丁醇部位以及水部位。考察茉莉花叶提取物对清除1,1-二苯基-2-三硝基苯肼(DPPH)自由基、ABTS^+自由基、O^2-自由基、OH^-自由基的能力以及对还原Fe³⁺、螯合Fe²⁺的能力,并与2,6-二叔丁基-4-甲基苯酚(BHT)进行对照。结果茉莉花叶不同极性部位提取物对DPPH自由基和ABTS^+自由基都具有清除能力,清除氧阴离子自由基的能力石油醚部位最强,清除羟自由基的能力为正丁醇部位>乙酸乙酯部位>石油醚部位>水部位,还原Fe³⁺的能力中水部位的还原能力最强,乙酸乙酯部位的还原能力最弱,乙酸乙酯部位螯合Fe²⁺的能力高于BHT,正丁醇部位的螯合力最弱。结论广西茉莉花叶不同极性部位提取物具有一定的抗氧化活性。     

Inhibitory effect of Lysichiton camtschatcense extracts on Fe2+/ascorbate-induced lipid peroxidation in rat kidney and brain homogenates

Lysichiton camtschatcense is a well-known plant in Japan where it has been used as a traditional medicine by the “Ainu” people for the treatment of acute nephritis. It is presumed that L. camtschatcense has an inhibitory effect against nephritis caused by reactive oxygen species (ROS) owing to its antioxidant activities. Consequently, the antioxidant effect of L. camtschatcense extracts was assessed against Fe²⁺/ascorbic acid (AsA)-induced lipid peroxidation in rat kidney and brain homogenates. The antioxidant effect of the chloroform extract (CE) was more potent than that of the methanol extract (ME) for both homogenates. The antioxidant effect of both extracts was similar to those of α-tocopherol, a lipid-soluble antioxidant, and glutathione (GSH), a water-soluble antioxidant, which were used as reference compounds. Although CE showed a low radical-scavenging effect for superoxide anion radicals (O₂^·−) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals, assessed by using an electron spin resonance (ESR) method, hydroxyl radicals (·OH) were markedly scavenged by more than 80%. On the other hand, ME showed more significant scavenging effect for DPPH radicals and O₂^·− than CE. These results suggest that the inhibitory effects of the L. camtschatcense extract on lipid peroxidation in rat kidney and brain are based on its high radical-scavenging effect against ·OH, O₂^·−, and lipid-derived radicals generated from the cell membrane.     

Isolation and identification of antioxidants from Pedilanthus tithymaloides

A bioassay-guided methodology utilizing 2,2-diphenyl-1-picrylhydrazyl (DPPH), the trolox equivalent antioxidant capacity (TEAC), and reducing power assays, as well as an assessment of scavenging properties against O₂^·−, H₂O₂, HOCl, ROO·, ·NO, and ONOO⁻ were used to find the main antioxidant principles of Pedilanthus tithymaloides (Euphorbiaceae), a shrub used in traditional Cuban medicine. The principles were identified as kaempferol 3-O-β-D-glucopyranoside-6′′-(3-hydroxy-3-methylglutarate), quercitrin, isoquercitrin, and scopoletin. The contents of total phenolics and flavonoids were found to be 76.0 ± 4.8 mg of gallic acid equivalents/g extract and 9.8 ± 0.4 mg of rutin equivalents/g extract, respectively.     

Accumulation of phenolic compounds in in vitro cultures and wild plants of Lavandula viridis L’Hér and their antioxidant and anti-cholinesterase potential

In this study, we evaluated the phenolic profile, antioxidant and anti-cholinesterase potential of different extracts from wild plants and in vitro cultures of Lavandula viridis L’Hér. The HPLC–DAD analysis allowed the identification and quantification of 3-O-caffeoylquinic, 4-O-caffeoylquinic, 5-O-caffeoylquinic and rosmarinic acids, and luteolin and pinocembrin. Water/ethanol extract from in vitro cultures contained the highest amount of the identified phenolic compounds (51652.92 mg/kg). To investigate the antioxidant activity we used Trolox equivalent antioxidant capacity, oxygen radical absorbance capacity, Fe²⁺ chelation activity and the inhibition of Fe²⁺-induced lipid peroxidation in mouse brain homogenates (in vitro). Overall, all the extracts from both wild plants and in vitro cultures exhibited ability to scavenge free radicals, to chelate Fe²⁺ and to protect against lipid peroxidation. In addition, the extracts from L. viridis were active in inhibiting both acetylcholinesterase and butyrylcholinesterase (Ellman’s method). Our findings suggest that L. viridis in vitro cultures represent a promising alternative for the production of active metabolites with antioxidant and anti-cholinesterase activity.     

Comparative study of the antioxidant activity of some thiol-containing substances

Background  

Therapeutic thiol administration has been shown to have great potential in a variety of pathological conditions associated with oxidative stress. In the present study, the free radical scavenging effects against superoxide anion (O_2^- {\rm O}_{2^ - } ) and hydroxyl (·OH) radicals of captopril were compared with those of cysteamine and mercaptoethanol. Methods: The O_2^- {\rm O}_{2^ - } and ·OH were generated in vitro. Deoxyribose (DR) was used as a detector of ·OH radicals. The degradation of DR was measured in terms of the formation of thiobarbituric acid reactive substances, which were quantified spectrophotometrically. Superoxide anion radicals were generated photochemically and O_2^- {\rm O}_{2^ - } -produced nitro-blue tetrazolium (NBT) reduction was measured.     

鸭跖草总黄酮的大孔树脂纯化工艺及抗氧化活性研究

【】目的：研究鸭跖草(Commelina communis L.)总黄酮的大孔树脂纯化工艺及其抗氧化活性。方法：以静态饱和吸附量和解析率为指标,对3种大孔树脂(D101,NKA-9,AB-8)进行筛选,并以回收率为指标,通过选用L₉(3₄)正交表设计实验,确立纯化总黄酮的最佳条件;以V_C为对照品,测定鸭跖草总黄酮清除1,1-二苯基-2-苦肼基自由基(DPPH)、超氧阴离子(O_2- )和羟基自由基(.OH)的抗氧化活性。结果：AB-8纯化鸭跖草总黄酮效果最好,优于D101和NKA-9,最佳纯化工艺：上梯液质量浓度为1.482mg/ml,淋洗pH为4,乙醇洗脱液体积分数70％,洗脱流速为2ml/min;鸭跖草总黄酮对3种自由基的清除效率与浓度呈正相关,清除DPPH、超氧阴离子自由基、羟自由基的半数抑制浓度(IC₅₀)分别为0.0170mg/ml、0.0055mg/ml、1.9327mg/ml,对DPPH和羟自由基的清除作用弱于Vc,而对超氧阴离子的清除作用强于Vc,其中鸭跖草对超氧阴离子自由基的清除能力最强。结论：大孔树脂纯化鸭跖草总黄酮的效果显著,鸭跖草黄酮类化合物具有较强的抗氧化活性,值得进一步开发。     

赛庚啶对氧自由基的清除作用

赛庚啶(Cyp)对Fenton反应生成的·OH有较强的直接清除作用(EC₅₀为54μmol/L),并明显抑制·OH的生成速率(IC₅₀为22 μmol/L),且作用明显比·OH特异性清除剂甘露醇强(其EC₅₀和IC₅₀分别为22.7 mmol/L和10.7mmol/L)。Cyp对大鼠腹腔多形核白细胞(PMNs)产生的O₂也有一定的清除作用,其IC₅₀为179 μmol/L。提示Cyp的抗心肌损伤作用可能至少部分与其清除氧自由基作用相关。     

Antioxidant activity of food constituents: an overview

Recently, there has been growing interest in research into the role of plant-derived antioxidants in food and human health. The beneficial influence of many foodstuffs and beverages including fruits, vegetables, tea, coffee, and cacao on human health has been recently recognized to originate from their antioxidant activity. For this purpose, the most commonly methods used in vitro determination of antioxidant capacity of food constituents are reviewed and presented. Also, the general chemistry underlying the assays in the present paper was clarified. Hence, this overview provides a basis and rationale for developing standardized antioxidant capacity methods for the food, nutraceutical, and dietary supplement industries. In addition, the most important advantages and shortcomings of each method were detected and highlighted. The chemical principles of these methods are outlined and critically discussed. The chemical principles of methods of 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulphonate) radical (ABTS^·+) scavenging, 1,1-diphenyl-2-picrylhydrazyl (DPPH^·) radical scavenging, Fe³⁺–Fe²⁺ transformation assay, ferric reducing antioxidant power (FRAP) assay, cupric ions (Cu²⁺) reducing power assay (Cuprac), Folin-Ciocalteu reducing capacity (FCR assay), peroxyl radical scavenging, superoxide anion radical (O₂^·−) scavenging, hydrogen peroxide (H₂O₂) scavenging, hydroxyl radical (OH^·) scavenging, singlet oxygen (¹O₂) quenching assay and nitric oxide radical (NO^·) scavenging assay are outlined and critically discussed. Also, the general antioxidant aspects of main food components were discussed by a number of methods which are currently used for detection of antioxidant properties food components. This review consists of two main sections. The first section is devoted to main components in the foodstuffs and beverages. The second general section is some definitions of the main antioxidant methods commonly used for determination of antioxidant activity of components in the foodstuffs and beverages. In addition, there are given some chemical and kinetic basis and technical details of the used methods.     

A dimeric triterpenoid glycoside and flavonoid glycosides with free radical-scavenging activity isolated from <Emphasis Type="Italic">Rubus rigidus</Emphasis> var. <Emphasis Type="Italic">camerunensis</Emphasis>

The aerial part of Rubus rigidus var. camerunensis (Rosaceae) is used to treat respiratory and cardiovascular disorders in the Cameroonian traditional medicine. The ethanol extract exhibited more potent antioxidant activity (E_maxs of 119% and 229% activity on DPPH and β-carotene test) than aqueous extract. Bioactivity-guided fractionation of the ethanol extract based on free radical-scavenging assay (DPPH assay) afforded five flavonoid glycosides (four flavonol glycosides and an anthocyanin) and three glucosides of 19α-hydroxyursane-type triterpenoid (two monomeric and one dimeric triterpenoids). The flavonoids were identified as kaempferol 3-O-(2″-O-E-p-coumaroyl)-β-D-glucopyranoside (1), kaempferol-3-O-β-D-glucopyranoside (astragalin, 2), kaempferol-3-O-α-L-arabinofuranoside (juglanin, 3), quercetin-3-O-β-D-glucopyranoside (isoquercitrin, 4), pelargonidin-3-O-β-D-glucopyranoside (callistephin, 5). The three triterpenoids were 2α, 3β, 19α, 23-tetrahydroxyurs-12-ene-28-O-β-D-glucopyranosyl ester (nigaichigoside F₁, 6), 2α, 3β, 19α-trihydroxyurs-12-ene-23-carboxyl-28-O-β-D-glucopyranosyl ester (suavissimoside R₁, 7) as monomeric triterpenoids and coreanoside F₁ (8) as a dimeric triterpenoid. The flavonoids exhibited potent antioxidant activities (66 to 93.56% against DPPH radical) and they were also active on β-carotene test. Coreanoside F₁ exhibited a 63% antioxidant activity, meanwhile the other two triterpenoids showed a weak activity. Three important facts on structure-activity relationship were observed: Compound 8, a dimeric triterpenoid glycoside, strongly enhanced antioxidant activity of its monomers, compound 3 with 3-O-α-L-arabinofuranyl has much more potent activity than compound 2 with 3-O-β-D-glucopyranosyl, and antocyanin (5) is more potent than its corresponding flavonol glycosides.     

Antioxidant activities of bark extract from mangroves, Bruguiera cylindrica (L.) Blume and Ceriops decandra Perr

Objectives:

The antioxidant activities of two Indian mangrove plants, Bruguiera cylindrica and Ceriops decandra, were investigated.

Materials and Methods:

Total phenolics and total flavonoid contents of the mangroves were determined using folin-ciocalteu reagent method and aluminium chloride method, respectively. Antioxidant capacity was assessed by the following methods: 1,1-diphenyl-2-picryl hydroxyl (DPPH.) quenching assay; 2,2’- azinobis-3-ethylbenzothiozoline-6-sulfonic acid (ABTS.⁺) cation decolorization test; scavenging capacity towards hydroxyl ion radicals (.OH); reductive capacity; and antihemolytic activity.

Results:

The mangroves yielded 233.3 ± 0.062 and 283.31 ± 0.04 mg gallic acid equivalent/g phenolic contents and 11.6 ± 0.12 and 15.1 ± 0.02 mg quercetin equivalent/g flavonoid contents. The methanol extracts of both mangroves exhibited high antiradical activity against DPPH., ABTS.⁺, and .OH radicals. The reductive capacity of the extracts increased with increasing concentration of samples. The extracts also inhibited H₂O₂ induced hemolysis in cow blood erythrocytes. The antioxidant activities were found stronger than that of the reference standard, butylated hydroxy toluene (BHT). The antioxidant activity of mangrove plants was correlated with total phenolics and flavonoid contents.

Conclusion:

Both plants can be considered as good sources of natural antioxidants for medicinal uses. Further studies are necessary to isolate active principles responsible for the overall antioxidant activity of the extracts.     

白术挥发油GC-MS指纹图谱与抗氧化活性的谱效关系研究

目的 研究白术挥发油指纹图谱与抗氧化活性的谱效关系,筛选主要抗氧化活性成分。方法 采用GC-MS测定不同产地的15批白术饮片挥发油指纹图谱,通过清除1,1-二苯基-2-苦腈基（DPPH）和Fe³⁺还原/抗氧化能力法测定白术挥发油的抗氧化能力,运用偏最小二乘回归法进行数据分析,研究白术挥发油指纹图谱和抗氧化活性的相关性,并筛选活性色谱峰。结果 28个匹配指纹峰中,对挥发油清除DPPH自由基活性贡献度最大的前5个峰依次为：峰11 > 峰25 > 峰2 > 峰4 > 峰24;对挥发油还原Fe³⁺能力贡献度最大的前5个峰依次为：峰11 > 峰8 > 峰14 > 峰19 > 峰26。其中峰11的峰面积与挥发油清除DPPH自由基能力和还原Fe³⁺能力均呈正相关。通过与对照品比对确定峰11为苍术酮,并具有显著的抗氧化活性。结论 苍术酮不仅是白术挥发油的主要成分,还是主要的抗氧化活性物质。