山茱萸多糖体外清除自由基和抗氧化作用研究

目的:研究山茱萸多糖提取物的体外抗氧化活性。方法:采用乙醇脱脂、热水提取、酶-Sevage法除蛋白、不同比例乙醇分级沉淀等方法获得山茱萸多糖提取物。分别采用Fenton反应体系、氮蓝四唑(NBT)光化还原法以及烘箱自氧化法研究山茱萸多糖的抗氧化性能,比较不同比例乙醇沉淀所得多糖的抗氧化活性。结果:不同乙醇浓度沉淀所得山茱萸多糖均具有一定的抗氧化活性,且呈显著的量效关系。其中,50%醇沉多糖对自由基的清除作用最为显著,当多糖质量浓度达到1.2mg/mL时,其对羟基自由基及超氧自由基的清除率分别为89.9%和87.1%。而90%醇沉多糖则具有较强的油脂抗氧化能力,其对猪油的抗氧化能力几乎与天然抗氧化剂BHT相当。结论:山茱萸中50%醇沉多糖及90%醇沉多糖分别具有较强的清除自由基能力和油脂抗氧化能力,是天然抗氧化剂的良好来源,可以进一步分离纯化。     

保健食品清除自由基作用的体外测定方法和原理

综述了抗氧化保健食品清除O2·、·OH、H2O2和DPPH·自由基作用的体外实验方法和原理。检测保健食品清除自由基的体外实验方法有多种,一般采用化学方法在体系中产生自由基,通过测定自由基与体系中的化学物质或离体组织成分反应所产生的颜色变化、发光现象等间接测定自由基含量或根据氧张力的变化等直接测定自由基含量。当体系中加入有清除自由基作用的保健食品功效成分后,体系中的自由基含量会减少,由此确定保健食品清除自由基能力的高低。体外实验的特点是快速、灵敏,可对保健食品清除自由基作用进行初步分析评价,适用于筛选抗氧化保健食品功能材料。     

马尾松树皮中原花青素体外抗自由作用的研究

目的:对马尾松树皮中原花青素的体外抗自由基作用进行了研究.方法:采用邻二氮菲法和邻苯三酚法研究原花青素抗羟自由基和抗超氧自由基的能力,并以抗坏血酸和SOD酶为对照进行研究.结果:马尾松树皮中原花青素对羟自由基和超氧自由基都有较好的清除能力,都分别明显高于抗坏血酸和SOD酶.结论:马尾松树皮中原花青素能够清除自由基,有较好的抗氧化能力.     

葡萄酵素在天然发酵过程中体外抗氧化性能的变化

研究葡萄酵素在天然发酵过程中体外抗氧化能力的变化。以还原力、DPPH自由基清除能力、超氧自由基清除能力、羟基自由基清除能力和ABTS自由基清除能力为指标,多体系地考察发酵过程中抗氧化性能的变化,并进行相关性分析。试验结果表明,发酵过程中总酚含量从1.460 mg/m L升高到1.739 mg/m L,发酵前、后增加了19.1%,还原力、DPPH自由基清除能力、羟基自由基清除能力和ABTS自由基清除能力呈逐渐上升趋势,发酵前、后分别提高了17.2%,12.5%,7.0%和17.2%,超氧自由基清除能力呈先升高后略微降低再升高的趋势,发酵前、后提高了12.8%;还原力、DPPH自由基清除能力、超氧自由基清除能力、羟基自由基清除能力和ABTS自由基清除能力与总酚含量均具有显著的正相关性,相关系数分别为0.959,0.869,0.926,0,920,0.953,P0.01。葡萄酵素在发酵过程中展现良好的抗氧化性能,抗氧化性能总体呈现上升趋势,与酚类物质变化相关性较大。     

牛蒡根中抗氧化活性和黄酮含量的测定

采用食用酒精浸泡提取传统食药两用植物牛蒡根成分,并用石油醚、乙酸乙酯和正丁醇依次进行萃取,利用DPPH自由基清除法、超氧自由基清除法以及对羟基自由基的清除作用测定其抗氧化活性,同时与抗坏血酸(Vc)和叔丁基对苯二酚(TBHQ)等进行了对比,通过标准曲线法对抗氧化活性强的部位进行了黄酮含量的测定。结果显示,传统食药两用植物牛蒡根提取物具有较好的体外抗氧化活性,尤其是乙酸乙酯萃取物清除DPPH自由基的能力,活性强于TBHQ,几乎与Vc相当,其黄酮含量达29%,食药两用植物牛蒡根有望成为抗衰老、抗氧化的资源。     

葡萄酵素有机酸分析及其体外抗氧化性能

研究葡萄酵素中有机酸种类与含量及其体外抗氧化性能。采用高效液相色谱法测定其有机酸种类及含量。以还原力、DPPH自由基清除能力、超氧自由基清除能力、羟基自由基清除能力和ABTS自由基清除能力为抗氧化性指标,在多体系考察其体外抗氧化性能。结果表明,葡萄酵素以酒石酸、乙酸和柠檬酸为主,同时因发酵代谢积累了丙酮酸、莽草酸和富马酸。葡萄酵素的还原力、DPPH自由基清除能力、超氧自由基清除能力、羟基自由基清除能力和ABTS自由基清除能力均表现出浓度依赖性。在试验浓度范围,葡萄酵素对超氧自由基和羟基自由基的清除能力优于VC对照,且对羟基自由基有特别强的清除能力。结论:葡萄酵素含有丰富的有机酸,其中部分来自于微生物的发酵代谢,具有良好的自由基清除能力。其原因归咎于有机酸、多酚、维生素和SOD酶的协同作用。     

提取方式对玉米须总多酚抗氧化活性的影响研究

以玉米须为原料,利用酶法、微波、超声波和微波辅助超声波四种方式提取玉米须中的多酚,并研究了不同提取方式得到多酚的抗氧化活性。通过测定多酚的体外还原能力以及DPPH自由基、超氧自由基、羟基自由基和ABTS自由基的清除能力,考察四种提取方式得到多酚的抗氧化活性并进行比较。结果表明,微波辅助超声波提取得到的多酚含量最高,为1.975 mg/g;四种提取方式得到的多酚对DPPH自由基、超氧自由基、羟基自由基和ABTS自由基均具有较强的清除作用,且相关性显著,其中酶法提取多酚的清除能力均强于其余三种提取方式的清除能力,抗氧化活性由强到弱依次为酶法提取微波辅助超声波提取微波提取超声波提取。     

香樟内生细菌的分离与发酵产物抗氧化活性评价

目的:分离香樟内生细菌,评价内生细菌发酵产物抗氧化活性,为香樟开发及其内生细菌作为天然抗氧化活性物奠定基础。方法:采用组织块分离和组织匀浆法分离香樟内生细菌,通过测定发酵上清液的总还原力,以及其对DPPH自由基、超氧自由基和羟自由基等的清除能力,评价内生细菌发酵产物抗氧化活性,并通过16S rRNA基因序列分析对内生细菌进行初步鉴定。结果:从香樟枝条、叶及果实等组织中共获得64株内生细菌,总还原力测定表明67.19%内生菌的发酵产物具抗氧化活性。香樟内生细菌发酵产物对DPPH自由基的清除能力强于对超氧自由基和羟自由基的清除能力。其中,对DPPH自由基具清除能力的内生菌占62.50%,平均清除率为73.96%;对超氧自由基具清除能力的占12.50%,平均清除率为16.49%;对羟自由基具清除能力的仅占6.25%,平均清除率为6.07%。初步鉴定表明,具抗氧化活性的内生细菌均为芽孢杆菌属(Bacillus)。结论:香樟内生细菌发酵产物具较强的抗氧化活性,可作为筛选开发天然抗氧化剂的潜在资源。     

宁夏野生锁阳多糖的提取工艺及体外抗氧化活性研究

通过传统的热水浸提取方法对宁夏野生锁阳多糖进行提取,在单因素基础之上采用响应曲面法优化提取工艺,得到最佳提取工艺参数为:料液比1∶25g/m L,提取时间2.5h,提取温度90℃,在此条件下锁阳多糖的得率为:22.32%。此外,体外抗氧化性实验采用总还原能力、DPPH自由基的清除能力、超氧阴离子自由基的清除能力、羟自由基的清除能力作为锁阳多糖的体外抗氧化作用评价的指标,并与VC进行了比较。表明锁阳多糖具有一定的总还原能力及清除自由基的作用,锁阳是一种具有抗氧化活性的天然中药材。     

辣木抗氧化成分提取方法和抗氧化能力研究进展

辣木富含多种营养成分和生物活性物质,其抗氧化作用已成为近年来辣木研究与开发的热点。生物体内的氧化应激会造成衰老、慢性病的产生,辣木可作为天然的抗氧化剂,减缓这种损伤。本文总结了辣木中有抗氧化作用的多糖、多酚和维生素类成分及此类成分的提取方法、含量分布情况、抗氧化作用机制;整理了辣木的体内外抗氧化评价方法,包括1,1-二苯基-2-三硝基苯肼法(DPPH)、2,2-联氮-二(3-乙基-苯并噻唑-6-磺酸)二铵盐法(ABTS)、铁离子还原/抗氧化能力法(FRAP)、总抗氧化能力法(TRAP)、氧自由基吸收能力法(ORAC)等体外自由基清除方法和超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、谷胱甘肽过氧化氢酶(GPx)、谷胱甘肽-S-转移酶(GST)等体内酶活性测定方法。还对辣木的发展趋势进行展望,旨为辣木抗氧化活性成分及方法的深入研究和开发提供参考。     

Polyphenolic compounds and antioxidant properties of selected China wines

Thirty-seven China wines, produced from different geographical origins, were examined in this study. The antioxidant activity of wines was measured by different analytical methods: oxygen radical absorbance capacity (ORAC), reducing power, 2,2-azino-di-(3-ethylbenzothialozine-sulphonic acid) (ABTS), 2,2-diphenyl-1-picrylhydrazyl (DPPH·), hydroxyl radical-scavenger activity, superoxide radical-scavenger activity, lipid peroxidation and chelating capacity. Furthermore,total phenols, total flavonoids, total flavanols and total anthocyanins of wines were determined. As expected, the red wines had much higher phenolic content and antioxidant capacity than rosé wines or white wines. Among the red wines, Cabernet Sauvignon and Muscat Hamburg, respectively, represented the wines with the highest and lowest phenolic contents and antioxidant capacity. Among the white wines, Italian Riesling had the lowest phenolic content and antioxidant capacity. Taken together, a close relationship between phenolic contents and antioxidant capacity, for all wines, was observed.     

A Comparative Study of the Analysis of Antioxidant Activities of Liquid Foods Employing Spectrophotometric, Fluorometric, and Chemiluminescent Methods

The antioxidant profile of liquid foods is complex and includes different lipid and water-soluble compounds. These should be considered when assessing total antioxidant capacity (TAC) of these beverages, since it may act synergistically rather than individually. This study describes and compares the use of spectrophotometric methods (Trolox equivalent antioxidant capacity, TEAC and 2,2-diphenyl-1-picrylhydrazyl, DPPH), fluorometric (oxygen radical antioxidant capacity, ORAC), and photochemiluminescence (PCL) for the measurement of the TAC of different liquid foods (fruit juice mixed with milk and vegetables beverage). An evaluation was also made for the influence of certain compounds (ascorbic acid, phenolic compounds, total carotenoids, and tocopherols) with antioxidant capacity that was present in the samples studied. The different methods studied allow the determination of the TAC of the analyzed foods in a precise and accurate way. The TAC values in the studied samples differ from the applied method. An overall antioxidant potency composite index was calculated by assigning each test's equal weight. When an index score was applied, ORAC method had the higher antioxidant capacity values in the analyzed liquid foods in comparison with the other methods. The correlations among the different methods used for the determination of the antioxidant capacity depend on food, that is, mainly due to compounds (lipid and water soluble) of the different food matrix. In addition, ascorbic acid was the main contributor to antioxidant capacity of fruit juice mixed with milk beverages measured with the different methods. However, in vegetables beverages, phenolic compounds were found to correlate more significantly with antioxidant capacity values.     

Screening of cereal varieties for antioxidant and radical scavenging properties applying various spectroscopic and thermoanalytical methods

Twenty varieties of four representative cereals, and sixteen varieties of six pseudocereals were investigated by different assays and analyses, covering the quantitative analysis of antioxidants, radical scavenging capacity (RSC) as well as total antioxidant capacity of cereals. The inter-variety variability in antioxidant capacity was determined by four independent methods for evaluation of antioxidant activity including 2,2'-azinobis-(3-ethylbenzthiazoline)-6-sulphonic acid (ABTS) and 2,2-diphenyl-1-picrylhydrasyl (DPPH) tests, electron paramagnetic resonance (EPR)/spin-trapping assay and differential thermal analysis (DTA). The antioxidant capacity of studied samples determined in ABTS test ranged from 0.70 to 7.33 mg Trolox g⁻¹, in DPPH test from 1.31 to 54.79 mg Trolox g⁻¹and RSC values from EPR/spin-trapping assay varied from 0.27 to 13.52 mg Trolox g⁻¹ dry matter. The best antioxidant capacity was found for buckwheat ( Fagopyrum esculentum Moench), barley ( Hordeum vulgare L.) and Japanese millet ( Echinochloa frumentacea L.), where also the highest contents of total phenolics and exceptional thermal stability were observed.     

In vitro antioxidant capacity of honeybee-collected pollen of selected floral origin harvested from Romania

Total phenolic phytochemical concentration was measured in 12 honeybee-collected pollens of selected floral species as well as their antioxidant capacity. The content of total polyphenols was measured spectrophotometrically using the Folin–Ciocalteu reagent with gallic acid as standard. The antioxidant properties were evaluated by 2,2-diphenyl-picrylhydrazyl radical scavenging capacity (DPPH) assay, Trolox equivalent antioxidant Capacity procedure and Ferric ion reducing antioxidant power assay. A great variability regarding the correspondence between the antioxidant activity and the content of total polyphenols of honeybee-collected pollens with different botanical origin was found. Antioxidant activities were different for each floral species and were not clearly associated to their total phenolic content.     

COMPARISON OF CHEMICAL COMPOSITION AND ANTIOXIDANT ACTIVITY OF GLYCOSIDICALLY BOUND AND FREE VOLATILES FROM CLOVE (EUGENIA CARYOPHYLLATA THUNB.)

The present article reports on the chemical composition and antioxidant activity of clove glycosidically bound volatile compounds in comparison with their essential oil. The comparison of chemical composition of volatile aglycones with the chemical composition of essential oil revealed only eugenol as identical. To measure the antioxidative activity of the clove enzymatically released aglycones and its essential oil, two different assays were performed: the 2,2'-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging method and the ferric reducing/antioxidant power (FRAP) assay. Both methods showed that the clove volatile aglycones possess lower antioxidant properties than its essential oil. The volatile aglycones radical-scavenging activity measured by DPPH method was lower than butylated hydroxytoluene (BHT) and butylated hydroxyanisole (BHA) activity. The reducing capacity measured by FRAP method for volatile aglycones was lower than BHA capacity and higher than BHT capacity. Some differences in activity obtained by two methods could be explained with different solvent polarity.

PRACTICAL APPLICATIONS

Many secondary metabolites are glycosylated and accumulate as nonvolatile glycosides. Since the glycosides are able to release their aglycones by enzymatic hydrolysis, these compounds could be considered as possible precursors of antioxidant substances in plant. They may contribute to the total antioxidant activity of plant and could be used as natural antioxidants.     

Antioxidant evaluation protocols: Food quality or health effects

Increasing research on natural antioxidants in foods and development of new assays has prompted critical reflection on the field. It has been common practice to identify health benefits from antioxidant activity on the cellular level with antioxidant capacity of food measured in vitro. The use of antioxidants and their positive effects on food quality has been demonstrated in a large variety of foods and beverages using various methods for detection of lipid and protein oxidation or various assays based on electron transfer or hydrogen-atom transfer. A direct positive effect on markers of oxidative status after dietary intervention has, however, been difficult to confirm and much has still to be learnt about antioxidant action in vivo including synergistic or inhibitory roles, the uptake, biotransformation, and tissue distribution of potential antioxidants. This review critically evaluates various types of assays for antioxidative capacity, i.e. the stoichiometry, and antioxidative activity, i.e. the kinetics of the antioxidant action, with focus on the antioxidant mechanism of natural dietary antioxidants, particularly phenolic compounds, on lipid oxidation. It is concluded that it is difficult to transfer antioxidant mechanisms established in model systems and in foods to the in vivo situation and that no simple relationship has been recognized so far between antioxidant capacity determined for various foods and beverages and health benefits for humans. Screening of antioxidant capacity using simple assays in order to predict positive health effects of food are not scientifically justified. Different protocols will have to be used for evaluation of the protection of food by antioxidants and for evaluation of the health effect of antioxidants.     

云南大叶种茶树花生化成分及体外抗氧化活性研究

本文对云南大叶种茶树花的生化成分和体外抗氧化活性进行了研究。实验对13个云南大叶种茶树花的主要生化指标与1,1-二苯基-2-三硝基苯肼（1,1-diphenyl-2-picrylhydrazyl,DPPH）自由基清除能力、2,2'-联氮-双-3-乙基苯并噻唑啉-6-磺酸（2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid),ABTS）自由基清除能力、总抗氧化能力（Total antioxidant capacity,TAC）、羟自由基（·OH）清除能力、超氧阴离子清除能力,5种体外抗氧化指标进行测定,主要生化成分和体外抗氧化指标进行了相关性分析。结果表明:茶树花水浸出物、茶多酚、氨基酸含量范围分别为41.22%~63.73%、7.74%~13.56%、1.61%~5.91%;咖啡碱、黄酮含量分别为4.98~8.46、4.21~8.63 mg/g,样品间生化含量及组成表现出一定的差异性。不同茶树花样品体外抗氧化能力存在显著性差异（P<0.05）。其中,地界古茶树花、布朗山古茶树花、冰岛古茶树花抗氧化活性表现良好,而秧塔大白茶古茶树花最弱。茶树花体外抗氧化活性与生化指标呈现相关性,茶多酚含量与总抗氧化能力极显著相关（P<0.01）,表没食子儿茶素没食子酸酯（Epigallocatechin gallate,EGCG）、表儿茶素没食子酸酯（Epicatechin gallate,ECG）含量与总抗氧化能力显著相关（P<0.05）,结果可作为预测茶树花抗氧化活性的重要指标。     

Bioactive composition and antioxidant potential of different commonly consumed coffee brews affected by their preparation technique and milk addition

Coffee is one of the most popular beverages in the world, prepared and consumed in many different ways. Taste, aroma and composition of the coffee brew vary depending on the preparation method. Therefore, this study investigates the effect of different brewing methods on the polyphenol and methylxanthine composition and antioxidant capacity of thirteen different coffee brews. The content of total phenols and flavonoids was determined spectrophotometrically and the content of chlorogenic acid derivates (3-CQA, 4-CQA and 5-CQA) and caffeine using the high performance liquid chromatography (HPLC-PDA). Antioxidant capacity of coffee brews was evaluated by using the ABTS (2,2-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid)) and FRAP (ferric-reducing antioxidant power) assays. Instant coffee brews showed the highest values in content of total phenols, chlorogenic acid derivates, caffeine and antioxidant capacity, which significantly decreased by milk addition. The antioxidant capacity of coffee brews was in compliance with the total phenol content and content of chlorogenic acid derivates.     

朝鲜蓟花苞汁总酚、总黄酮、抗氧化性比较及体外模拟胃肠消化特性

比较不同部位花苞汁及体外模拟胃肠消化前后总酚、总黄酮质量浓度,并通过总还原力和1,1-二苯基-2-三硝基苯肼自由基、2,2’-联氮-双-3-乙基苯并噻唑啉-6-磺酸阳离子自由基、超氧阴离子自由基清除率4 种方法评价其抗氧化能力。结果表明：花托汁总酚质量浓度为2.46 mg/mL,分别为内苞叶汁、外苞叶汁的1.13、1.94 倍;总黄酮质量浓度为6.53 mg/mL,分别为内苞叶汁、外苞叶汁的1.15、2.06 倍。在4 种抗氧化评价体系中,自由基清除能力强弱顺序均为花托汁＞内苞叶汁＞外苞叶汁,且自由基清除率均随着样品总酚质量浓度增加而增大。在体外模拟胃肠消化实验中,以花托汁为样品,经过模拟胃液处理后,模拟胃液组和胃酸对照组抗氧化性均显著增强（P＜0.05）,但经过模拟肠液处理后抗氧化能力下降,表明胃蛋白酶、胃酸、胰蛋白酶均能促使抗氧化活性因子释放,提高抗氧化能力。     

4 个葡萄品种葡萄籽冷榨油的性质与体外抗氧化活性

目的：评价4 种葡萄籽冷榨油脂肪酸组成、总酚含量及体外抗氧化活性。方法：收集单品种葡萄籽榨油,气相色谱法测定脂肪酸组成,Folin-酚法测定总酚含量,用1,1-二苯基-2-三硝基苯肼（1,1-diphenyl-2-picryhydrazyl,DPPH）法、2,2’-联氮双-（3-乙基苯并噻唑林-6-磺酸）二胺盐（2,2’-azinobis(3-ethylbenzothi azoline-6-sulfonic acid)ammonium salt,ABTS）法、Fenton反应和总抗氧化能力法分析其体外抗氧化能力。结果：4 个品种葡萄籽冷榨油均富含亚油酸（72.77%～77.36%）,不饱和脂肪酸含量为88.12%～91.06%;总酚含量为60.77～100.53 μg GAE/g,爱格丽葡萄籽冷榨油总酚含量最高,其次是北冰红、媚丽、赤霞珠葡萄籽冷榨油;4 个品种的葡萄籽冷榨油都有良好的清除DPPH自由基和ABTS＋·的能力,且随着葡萄籽冷榨油浓度的增大,清除能力增强,清除DPPH自由基的IC50变化范围为10.19～13.82 mg/mL,清除ABTS＋·的IC50变化范围为11.62～19.25 mg/mL;清除羟自由基（·OH）的能力范围为13.18～27.08 U/mL;总抗氧化能力范围为1.08～3.68 U/mL。4 个品种的葡萄籽冷榨油的体外抗氧化能力强弱顺序为爱格丽＞北冰红＞媚丽＞赤霞珠。