咖啡酸衍生物对自由基致DNA氧化损伤的联合保护作用

目的:探讨咖啡酸衍生物(CADs):绿原酸(Chlorogenic acid,ChA)、阿魏酸(Ferulic acid,FeA)、迷迭香酸(Rosmarinic acid,RoA)对自由基致DNA损伤的联合抑制保护效果.方法:运用DPPH自由基及羟自由基反应模型观察不同组成的CADs对自由基的淬灭效应,以CuS04-Phen-VitC-H202-DNA化学发光体系测定不同成分的多酚类物质对·OH致DNA损伤的抑制作用.结果:在30min时间内,三种CADs联合组在浓度为25、50、100、200μg/mL时,对DPPH·清除率分别为28.93％、58.39％、83.93％和84.09％;对·OH清除率分别为33.43％、55.27％、71.23％、77.49％.在DNA化学发光体系中,在25～200μg/mL范围内,三种CADs联合组对DNA损伤产物发光抑制率为12.49％～81.09％.结论:CADs能有效清除DPPH自由基和羟自由基,抑制羟自由基引发的DNA损伤程度,并延迟其受损伤的时间.在各实验组中三种CADs联用组在对DPPH自由基清除率、DNA损伤产物发光抑制率以及保护DNA损伤的能力均最强,体现出协同作用.     

腊梅花提取物抗氧化作用研究

利用比色法、化学发光法,研究了腊梅花提取物体在体外对O2·,·OH,DPPH·活性氧自由基的清除作用。实验结果表明腊梅花提取物对O2·,·OH,DPPH·自由基均有明显的清除作用,其50%抑制浓度(IC50)分别为147.25,47.71,25.90μg/ml。     

金丝小枣中多酚类物质的体外抗氧化活性研究

采用酒石酸铁法测定金丝小枣枣皮、枣核中的多酚类物质含量。首次利用化学发光分析和紫外-可见分光光度分析相结合的方法测定金丝小枣枣皮、枣核中间苯三酚和邻苯二酚的体外抗氧化活性及其清除自由基保护DNA等能力的变化规律。研究结果表明,间苯三酚和邻苯二酚对·OH、NO2-、DPPH具有较明显的抑制作用,对由·OH引起的DNA损伤也具有较好的保护作用。当间苯三酚和邻苯二酚质量浓度为60μg/mL时,体外抗氧化活性及清除自由基保护DNA作用最佳。本研究可为开发枣副产品的保健功能提供新的研究方向和理论基础。     

黄玉米粗类黄酮提取工艺正交试验优化及其体外抗氧化活性

以黄玉米纪元1号为材料,采用单因素试验与三元二次正交试验,考察乙醇体积分数、料液比、浸提温度及浸提时间对粗类黄酮提取量的影响及黄玉米粗类黄酮清除1,1-二苯基-2-苦肼基（1,1-diphenyl-2-picrylhydrazyl,DPPH）自由基和•OH的能力。得出最优工艺参数为料液比1∶35.5（g/mL）、69 ℃浸提1.85 h,此条件下粗类黄酮提取量为85.88 mg/g。当粗类黄酮质量浓度为20 mg/mL时,对DPPH自由基和•OH的清除率分别为76.47%和32.62%,分别相当于芦丁标准品（0.1、0.2 mg/mL）清除能力的81%～84%和40%～50%。黄玉米粗类黄酮对DPPH自由基的清除率明显大于对• OH的清除率,且随质量浓度提高,清除率显著提高（P＜0.05）。     

飞龙掌血多糖清除自由基活性的研究

目的：研究飞龙掌血多糖的抗氧化活性。方法：采用Fenton法、DPPH法测定飞龙掌血多糖清除羟基自由基（.OH）、二苯代苦味酰肼自由基（DPPH.）的能力,以VC为对照。结果：质量浓度在0.2～0.4mg/mL范围内,飞龙掌血多糖随浓度增大,清除.OH能力增强,且0.4mg/mL时清除率高达73.7%;质量浓度在5×10-3～5×10-1mg/mL时,对DPPH.的清除率为13.5%～79.5%,清除作用与浓度呈正相关,当浓度为0.5mg/mL时,清除率高达79.5%。结论：飞龙掌血多糖具有较强的体外抗氧化性能,对.OH、DPPH.具有明显的清除作用。     

响应曲面法优化海红果水溶性多糖提取工艺及抗氧化活性的研究

采用响应曲面法优化海红果水溶性多糖(MPB)提取工艺的条件。在单因素实验基础上依据回归分析确定最佳工艺条件为:提取温度86℃,提取时间4h,料液比1∶28g/mL,MPB的实际提取率可达8.33%。用MPB对羟基自由基(·OH)、超氧阴离子自由基(O2-·)、DPPH自由基进行清除能力和还原力的测定,研究MPB的抗氧化能力。结果表明,MPB对·OH、O2-·、DPPH均有一定的清除能力,对DPPH的清除作用尤为明显,当质量浓度达到1mg/mL时,清除率达到87.12%,接近VC的94.47%,且MPB清除DPPH的IC50值为1.181mg/mL。     

余甘子果核多酚提取工艺优化及抗氧化性研究

以广西崇左余甘子果核为原材料,通过单因素试验和正交试验设计优化超声波辅助提取余甘子果核多酚工艺条件,并以对羟基自由基（·OH）及1,1-二苯基-2-三硝基苯肼自由基（DPPH·）的清除效果评价余甘子果核多酚的抗氧化活性。结果表明,余甘子果核多酚的最佳提取工艺条件为使用体积分数70%丙酮、料液比1∶40（g∶mL）、提取温度40 ℃及提取时间30 min。在此优化条件下,余甘子果核多酚得率为7.37%。余甘子果核多酚对·OH和DPPH·的清除效果与浓度间存在正相关的量效关系,当余甘子果核多酚质量浓度为0.05 mg/mL时,对DPPH·的清除率为80.53%;当余甘子果核多酚质量浓度为3.0 mg/mL时,对·OH的清除率达84.44%,半抑制浓度（IC50）值为1.2 mg/mL。结果表明余甘子果核多酚具有一定的抗氧化活性。     

虾青素体外清除自由基活性的研究

目的:通过与VC的对比实验,研究虾青素的抗氧化能力。方法:分别采用DPPH自由基测定法、水杨酸法以及邻苯三酚自氧化法,研究虾青素和VC在清除DPPH自由基(DPPH·)、羟基自由基(·OH)和超氧阴离子(O2-·)的能力。结果:虾青素能有效地抑制羟基自由基、超氧阴离子自由基,且清除率大于VC,清除DPPH·自由基方面虽然略低于VC,但同样表现出较高的清除率,当浓度为90μg/mL时,清除率为95.0%。结论:虾青素具有明显的抗氧化活性。     

辣椒碱体外抗氧化作用研究

以辣椒碱标准品为原料,Vc为阳性对照,采取体外抗氧化试验模型研究其抗氧化活性。通过分析辣椒碱的还原力和清除DPPH自由基(DPPH·)、超氧阴离子自由基(O_2~-·)、亚硝基以及羟自由基(·OH)的能力,探讨辣椒碱的体外抗氧化性能。结果表明,辣椒碱的还原能力以及对DPPH·、亚硝基以及·OH的清除率随质量浓度的增加而升高,且清除效果与Vc基本相近,但对O_2~-·的清除率较低;辣椒碱对DPPH·、亚硝基以及·OH的IC_(50)分别为0.02,0.15,0.28mg/mL,说明辣椒碱清除DPPH·的效果较好。     

鼠曲草总黄酮的抗氧化活性研究

[目的]研究鼠曲草总黄酮的抗氧化活性。[方法]分别采用DPPH自由基法、羟基自由基法、对亚硝化反应的抑制作用和抗脂质氧化四种方法研究了鼠曲草总黄酮的抗氧化活性。[结果]当鼠曲草总黄酮浓度在13.33μg/mL 133.3μg/mL和10.67μg/mL 127.97μg/mL范围内,其对DPPH自由基和羟基自由基的清除率分别为7.09%55.71%和40.08%83.93%,且都存在明显的量效关系;0.12mg/mL的鼠曲草总黄酮溶液12mL对亚硝胺合成的阻断率可达69.66%,对NaNO2的清除率可达70.71%;鼠曲草总黄酮清除DPPH自由基、清除羟基自由基、阻断亚硝胺合成、清除NaNO2的IC50值分别为118.2μg/mL、16.3μg/mL、33.4μg/mL、17.8μg/mL。同时,质量浓度0.05%的鼠曲草总黄酮和0.02%的TBHQ的抗大豆油氧化能力相接近。[结论]鼠曲草总黄酮是一种天然有效的抗氧化剂,可用于保健食品、药品开发。     

Sweet potato (Ipomoea batatas [L.] Lam ‘Tainong 57’) storage root mucilage with antioxidant activities in vitro

Sweet potato storage root mucilage was extracted and purified by SDS and heating treatments. Total antioxidant activity, DPPH (1,1-diphenyl-2-picrylhydrazyl) staining, reducing power method, metal ion-dependent hydroxyl radical, FTC (ferric thiocyanate) method, and protection of calf thymus DNA against hydroxyl radical-induced damage were studied. Half-inhibition concentrations, IC₅₀, were 0.08 mg/ml and IC₅₀ > 0.1 mg/ml, respectively, for the crude and purified mucilage in the total antioxidant activity test. In the DPPH staining, the crude and purified mucilage appeared as white spots when they were diluted to 50 and 100 μg per application, respectively. Like total antioxidant activity, reducing power, scavenging capacity against hydroxyl radical, FTC activity and protection of calf thymus DNA against hydroxyl radical-induced damage were found in the mucilage. It is suggested that the mucilage might contribute its antioxidant activities against both hydroxyl and peroxyl radicals.     

鹰嘴豆抗氧化肽的分离纯化、鉴定及其抗氧化活性

以发芽鹰嘴豆为原料,制备鹰嘴豆抗氧化肽,采用葡聚糖凝胶对其进行分离纯化,通过测定自由基清除能力、还原力、脂质氧化抑制能力、对自由基诱导的蛋白质和DNA损伤的保护能力评价纯化肽的抗氧化活性。对纯化肽进行鉴定合成以验证其抗氧化活性,并对合成多肽进行安全性预测。结果表明,纯化后的多肽有较好的自由基清除能力、还原力,且对亚油酸自氧化有明显的抑制作用,对自由基诱导的蛋白质和DNA损伤有保护作用。经预测,合成多肽无毒性与致敏性。综上,发芽鹰嘴豆水解物具有抗氧化能力,可用来制备抗氧化肽,从而增加鹰嘴豆的利用价值。     

枣花蜜酚类化合物组成及其抗氧化活性分析

以陕西佳县、府谷、大荔、渭南4 个地区枣花蜜为研究对象,测定其理化指标、酚类化合物含量、体外抗氧化活性、对·OH诱导的pBR322质粒DNA氧化损伤的保护作用及过氧化氢（H2O2）诱导的小鼠淋巴细胞DNA氧化损伤的保护作用。结果表明,枣花蜜总酚含量为196.55～454.95 mg/kg,总黄酮含量为22.03～39.40 mg/kg;高效液相色谱-电喷雾-四极杆-飞行时间串联质谱分析发现枣花蜜中含有15 种酚类化合物,包括4 种酚酸和11 种黄酮类化合物;体外抗氧化实验表明,枣花蜜具有较强的1,1-二苯基-2-三硝基苯肼自由基清除能力（半抑制浓度为38.03～122.81 mg/mL）、Fe2＋络合能力（110.93～158.46 mg/kg）和Fe3＋还原力（166.68～365.06 mg/kg）;此外,枣花蜜对·OH诱导的pBR322质粒DNA氧化损伤有保护作用且能显著降低H2O2诱导的小鼠淋巴细胞DNA氧化损伤。本实验的研究结果可为枣花蜜资源的开发利用提供理论参考。     

白藜芦醇的体外抗氧化活性

通过对DPPH自由基、ABTS＋ ·的清除能力和还原力的测定,探讨白藜芦醇的抗氧化活性;并采用过氧化氢诱导红细胞自氧化模型和肝组织脂质过氧化反应模型,探讨白藜芦醇对自由基损伤和脂质过氧化反应的抑制作用。结果显示,白藜芦醇具有很强的清除自由基和抑制自由基引起的氧化损伤的能力。     

Identification of antioxidative oligopeptides derived from autolysis hydrolysates of sea cucumber (<Emphasis Type="Italic">Stichopus japonicus</Emphasis>) guts

Oligopeptides were prepared from the guts of sea cucumber Stichopus japonicus by autolysis method. Optimum autolysis conditions for preparing oligopeptides from the guts of sea cucumber were determined by response surface methodology using a central composite rotatable design. The effects of two independent variables, namely temperature and pH, on the response of trichloroacetic acid-soluble oligopeptides (mg/g on dry basis) were investigated. Regression analysis indicated that more than 95 % of the variation could be explained by the fitted models. Temperature at 48.30 °C and pH at 4.43 were found to be the optimal conditions to obtain oligopeptides from the guts of sea cucumber. The autolysis hydrolysates prepared at the optimized conditions were further fractionated into four major fractions (I–IV) by size exclusion chromatography on a Sephadex G-15 column. Fraction IV, which exhibited the highest DPPH radical scavenging capacity, Fe²⁺-chelating ability and protective effect against hydroxyl radical-induced DNA damage, was then analyzed by ESI–MS for molecular mass determination and ESI–MS/MS for the characterization of peptides. Two tetrapeptides (Val-Thr-Pro-Tyr and Val-Leu-Leu-Tyr) and a hexapeptide (Val-Gly-Thr-Val-Glu-Met) were found to exhibit protective effects against hydroxyl radical-induced DNA damage. These results suggest that antioxidant oligopeptides derived from the guts of sea cucumber by autolysis method could be utilized for functional foods.     

Antioxidant activity of enzymatic extracts from a brown seaweed Ecklonia cava by electron spin resonance spectrometry and comet assay

The potential antioxidant activity of enzymatic extracts from Ecklonia cava was evaluated by 1,1-diphenyl-2-picrylhydrazyl (DPPH), hydroxyl and alkyl radical scavenging using a electron spin resonance (ESR) spectrophotometer compared with ESR signal intensity and inhibitory effect of DNA damage on comet assay. E. cava was enzymatically hydrolyzed with five food industrial carbohydrases (AMG, Celluclast, Termamyl, Ultraflo and Viscozyme) from Novozyme Nordisk. All the tested extracts exhibited strong radical scavenging activities and the values were dose-dependent. The DPPH and hydroxyl radical scavenging activities of the enzymatic extracts were compatible with the vitamin C, which the alkyl radical scavenging activity was even higher than that of vitamin C. Also in the present study, the enzymatic extracts showed strong inhibitory effect against DNA damage in a dose dependent manner. These results indicated that the E. cava might be valuable natural antioxidative source.     

加热对橡子淀粉抗氧化活性的影响

探讨加热处理对橡子淀粉清除自由基能力的影响。加热处理2h淀粉颜色变化不显著。淀粉多酚含量随温度升高呈明显下降趋势。加热也导致淀粉清除自由基能力明显下降,但清除两类自由基能力的下降幅度差异明显。120℃热处理2h使橡子淀粉的清除羟自由基( ·OH)的能力下降56.2%,而DPPH自由基的清除能力则只降8%,结果显示对淀粉进行加热处理后其提取液对两类自由基的清除能力影响不同。     

Antioxidant activities of phlorotannins purified from Ecklonia cava on free radical scavenging using ESR and H2O2-mediated DNA damage

The potential antioxidant activities of three phlorotannins (phloroglucinol, eckol and dieckol) purified from Ecklonia cava collected in Jeju Island were investigated to evaluate their potential value as the natural products for foods or cosmetic application. In this study, antioxidant activities were measured by electron spin resonance spectrometry (ESR) technique for scavenging effects of free radicals such as 1,1-diphenyl-2-picrylhydrazyl (DPPH), alkyl, hydroxyl (HO^•) and superoxide anion radical (O₂ ^•−) and by comet assay for protecting effects against H₂O₂-mediated DNA damage. The results show that all the phlorotannins have the potential DPPH, alkyl, hydroxyl and superoxide radical scavenging activities. Especially, eckol samples scavenged around 93% of DPPH at 0.25, 0.5, 1 mg/mL of concentrations and were higher than the other phlorotannins, such as phloroglucinol and dieckol samples. Also, protecting effects of the phlorotannins against H₂O₂-mediated DNA damage increased with increased concentrations of the samples in the L5178 mouse T-cell lymphoma cell lines (L5178Y-R). In conclusion, these results suggest that the three phlorotannins purified from E. cava have the potential inhibitory effect on H₂O₂-mediated DNA damage and harmful free radicals and can be used as antioxidants in cosmetic, foods and drug industry.     

Purification and characterisation of an antioxidative peptide from enzymatic hydrolysates of duck processing by-products

Duck processing by-products were hydrolysed using eight proteases to produce an antioxidative peptide. Of the various hydrolysates produced, the pepsin extract exhibited the highest hydroxyl radical scavenging activity. The derived peptide was purified using high-performance liquid chromatography (HPLC) to identify any potent radical scavenging activity. The sequence of the antioxidative peptide obtained was identified as Asp-Val-Cys-Gly-Arg-Asp-Val-Asn-Gly-Tyr, with a molecular weight of 1096 Da. The IC₅₀ value of purified peptide for hydroxyl radical scavenging activity was 75 μg/ml as the measurement by an electron spin resonance (ESR) spectrometer. In addition, the purified peptide exhibited a protective effect on H₂O₂-induced DNA damage. These results indicate that the purified peptide possesses a potent antioxidative activity and protective effect of DNA against H₂O₂-induced oxidative damage.     

洋葱油的抗氧化活性研究

探讨洋葱油对羟基自由基、超氧阴离子自由基、过氧化氢的清除作用以及对羟基自由基引发DNA损伤的抑制作用,并与天然抗氧化剂Vc作比较。结果显示洋葱油对羟基自由基的清除作用及对羟基自由基引发DNA损伤的抑制作用效果明显,与Vc相当。对超氧阴离子自由基、过氧化氢的也有一定的清除作用,效果稍差于Vc。研究表明,洋葱油具有很好的抗氧化作用。