黑木耳黑色素抗氧化作用的研究

以黑木耳黑色素为实验材料,研究了抗小鼠脂质过氧化作用、抑制蛋黄的脂质过氧化作用、对羟基自由基的清除率的作用以及清除DPPH有机自由基的作用等.实验结果表明:黑木耳黑色素对小鼠正常肝匀浆、蛋黄有明显的抗氧化作用,抑制率达到50％时黑木耳黑色素浓度分别为0.065 mg/mL和0.110 mg/mL.浓度的增加有利于提高黑木耳黑色素对羟自由基的清除率,当黑色素浓度为0.48 mg/L时其清除率达到50％.黑色素浓度在0.05 mg/mL～0.24 mg/mL范围内对DPPH有机自由基的清除率逐渐增加,而大于0.24 mg/mL时抑制率有所下降.黑色素浓度达到0.176mg/mL时对DPPH有机自由基的清除率为50％.     

重组人乳铁蛋白抗氧化活性研究

目的考察重组人乳铁蛋白自身及其在奶粉中的抗氧化活性。方法通过二苯代苦味肼基(DPPH)自由基抑制率、羟基自由基抑制率、超氧阴离子自由基抑制率、还原能力和抑制大鼠肝脏体外脂质过氧化等试验评价重组人乳铁蛋白和牛乳铁蛋白的体外抗氧化性能。结果重组人乳铁蛋白和牛乳铁蛋白的浓度与DPPH自由基抑制率、抑制羟基自由基能力、抑制超氧阴离子自由基能力和还原能力之间呈明显剂量-效应关系,且差异有统计学意义(P0.05);样本和浓度之间没有交互作用,重组人乳铁蛋白和牛乳铁蛋白在不同浓度下所得值的趋势相同。重组人乳铁蛋白和牛乳铁蛋白在对大鼠肝组织匀浆抗氧化性影响差异有统计学意义(P0.05),不同浓度乳铁蛋白之间差异有统计学意义(P0.05)。结论重组人乳铁蛋白和牛乳铁蛋白具有一定的抗氧化活性,可以添加到保健品或者化妆品中作为天然抗氧化剂。     

石榴皮提取物体外抗氧化活性比较研究

研究石榴皮提取物的体外抗氧化作用。采用羟自由基(.OH)、超氧阴离子自由基(.O2-)、2,2-二苯代苦味酰基自由基(DPPH.)的生成体系,研究石榴皮提取物及绿茶多酚、没食子酸为对照,对自由基的清除能力和对小鼠肝组织匀浆脂质过氧化抑制作用。结果表明:石榴皮提取物对羟自由基、超氧阴离子、DPPH.的半清除率分别为I:C50=71.37 mg/mL、SC50=557.55 mg/mL、DC50=31.98 mg/mL;没食子酸对这3种自由基的半清除率分别为I:C50=51.85 mg/mL、SC50=289.2 mg/mL、DC50=37.65 mg/mL;绿茶多酚对这3种自由基的半清除率分别为:IC50=66.67 mg/mL、SC50=1043.91 mg/mL、DC50=22.48 mg/mL。石榴皮提取物对小鼠肝组织匀浆的脂质过氧化半抑制率EC50=5.21 mg/mL、没食子酸半抑制率EC50=22.82 mg/mL、绿茶多酚半抑制率EC50=3.47 mg/mL。研究表明石榴皮提取物较没食子酸和绿茶多酚具有良好的清除自由基及抑制脂质过氧化的能力。石榴皮提取物能有效清除羟自由基、超氧阴离子自由基、DPPH.自由基,抑制脂质过氧化作用,具有进一步研究和开发价值。     

桑葚醋提取物抗氧化性的研究

利用分光光度法测定了桑葚醋提取物羟基自由基清除率、脂质过氧化抑制率和总抗氧化能力。结果表明：桑葚醋提取物的抗氧化能力高于合成抗氧化剂BHA，羟基自由基清除率为79．57％，脂质过氧化抑制率为97．79％，体外总抗氧化能力为110．88mg／mL样品。     

蜂胶中总酚提取纯化工艺及抗氧化活性研究

为研究西藏蜂胶抗氧化活性,评估开发潜力,分析了西藏蜂胶及其模拟消化液的抗氧化成分（总酚和总黄酮）和活性（还原力、羟自由基清除能力（·OH清除率）、1,1-二苯基-2-三硝基苯肼自由基清除率（DPPH·清除率）、金属离子螯合率和脂质过氧化抑制率）。结果表明,西藏蜂胶总酚和总黄酮含量分别为7.02%和10.05%。模拟消化液的总酚和总黄酮含量持续降低,模拟胃液（消化2 h）总酚和总黄酮含量分别为0.43%和6.43%,模拟肠液（消化2 h）则为0.32%和5.11%。西藏蜂胶在1 mg/mL时,还原力、·OH清除率、DPPH·清除率、金属离子螯合率和脂质过氧化抑制率达到最高值,分别为0.35、96.60%、92.53%、19.96%和97.01%。模拟胃液还原力和DPPH·清除率的最高值比未消化时升高,分别为0.39和95.69%。·OH清除率、金属离子螯合率和脂质过氧化抑制率较未消化时降低。模拟肠液·OH清除率、金属离子螯合率和脂质过氧化抑制率较模拟胃液提高,最高值分别为99.72%、69.26% 和80.69%;还原力和DPPH·清除率则降低,但DPPH·最高清除率仍有74.74%。综上所述,西藏蜂胶具有较好的体外抗氧化活性,胃肠模拟消化对抗氧化各指标均有显著影响,各指标的变化趋势不一致,但多个指标仍有较好表现。西藏蜂胶可作为一种天然抗氧化剂进行后续研发。     

沙枣不同果、叶中多酚类物质抗氧化能力比较的研究

采用丙酮温浸法对尖果沙枣和大果沙枣果、叶中多酚物质进行提取并研究其抗氧化活性。通过测定不同材料多酚提取物对羟自由基（·OH）、超氧阴离子自由基（O2-·）以及2,2二苯代苦味肼基（DPPH·）的清除率,并利用硫代巴比妥酸法（TBA法）测定其对脂质过氧化的抑制作用。结果表明:八种实验材料中,尖果沙枣青果和嫩叶多酚提取物对·OH、O2-·、DPPH·均具有较好的清除作用,且清除率均高于50%,同时对脂质过氧化的抑制作用明显高于其余实验材料。尖果沙枣较大果沙枣具有更好的体外抗氧化活性。      

紫花松果菊挥发油抗氧化作用研究

目的:研究紫花松果菊挥发油抗氧化作用。方法:以VC和薰衣草挥发油做对照,分光光度法测定松果菊挥发油对DPPH.、.OH的清除率以及对卵磷脂过氧化的抑制率。结果:松果菊挥发油、薰衣草挥发油和VC对DPPH.清除能力表现为:松果菊挥发油>薰衣草挥发油>VC;对脂质过氧化的抑制能力表现为:松果菊挥发油>薰衣草挥发油>VC;对羟自由基清除能力表现为:VC>薰衣草挥发油>松果菊挥发油。结论:紫花松果菊挥发油具有抗氧化能力。紫花松果菊挥发油对DPPH.表现出清除作用,对脂质过氧化体表现出抑制作用,并且其清除和抑制能力高于两个对照组,而对.OH的清除作用低于对照组。      

水溶性和油溶性植物甾醇酯体外抗氧化活性研究

通过研究粉末状(水溶性)和油膏状(油溶性)植物甾醇酯(Phytosterol ester,PSE)对羟基自由基(·OH)、超氧阴离子自由基(O2-·)及DPPH自由基等的清除效果、对小鼠肝组织脂质过氧化反应的抑制作用及其对H2O2及紫外线诱导的DNA损伤的保护效果,深入探讨不同溶解特性PSE的体外抗氧化活性。实验结果表明,在清除·OH、DPPH自由基、O2-·及抑制肝组织脂质过氧化方面,油溶性PSE活性优于水溶性PSE;上述抗氧化活性的发挥呈剂量-效应关系,即低于最佳浓度时,其清除率随浓度增大而升高,超过最佳浓度后,样品对自由基的清除率则呈下降趋势;2种不同溶解特性的PSE发挥较好抗氧化活性的最佳作用浓度不同。此外,在实验浓度范围内水溶性PSE和脂溶性PSE在防止DNA氧化损伤和紫外线辐射损伤方面都具有一定的保护作用,保护效果随受试样品浓度升高而增强。     

杏鲍菇多肽生物活性的研究

以杏鲍菇多肽为原料,以清除DPPH·、O-2·等自由基、抑制脂质过氧化、抑菌和乳化特性为指标对其生物功能进行研究。结果表明,在实验浓度范围内,杏鲍菇多肽对DPPH·的清除率为85.94%、O-2·的清除率为80.66%,脂质过氧化抑制率为45.57%;同时多肽具有很好的乳化稳定性,其在2%浓度时,乳化稳定性可达206;此外其对金黄色葡萄球菌、沙门氏菌、大肠杆菌有较强的抑制作用,抑菌率分别为57.7%、55.5%、87.1%。      

玉米源活性肽对脂质过氧化的抑制作用研究

玉米肽具有良好的自由基和活性氧清除等抗氧化活性，但对其脂质过氧化抑制作用的报道较少。本文利用碱性蛋白酶、风味蛋白酶、中性蛋白酶以及模拟胃肠道消化（胰液酶+胃蛋白酶）水解制备玉米源活性肽，测定了不同蛋白酶所制备的玉米肽对ABTS自由基的清除活性，系统评价了其对亚油酸过氧化、蛋黄脂质过氧化和动物肝脏脂质过氧化的抑制作用。结果显示不同蛋白酶制备的玉米肽均具有一定的ABTS自由基清除活性以及脂质过氧化抑制作用，其中，模拟胃肠道消化所制备的玉米肽ABTS自由基清除活性最强，清除率最高达到（78.61±0.56）%；风味蛋白酶制备的玉米肽的亚油酸过氧化抑制作用最强，抑制率最高达到（72.54±1.15）%；碱性蛋白酶制备的玉米肽的卵黄脂质过氧化的抑制作用最强，抑制率最高达到（82.50±0.46）%；模拟胃肠道消化制备的玉米肽的动物肝脏脂质过氧化抑制作用最强，抑制率最高达到（61.96±0.34）%。本研究为提升玉米蛋白粉在食品领域的应用价值提供新思路，为玉米源活性肽的脂质过氧化抑制作用及其在脂质食品中的应用提供了依据。     

Radical scavenging activity and phenolic compounds in persimmon (Diospyros kaki L. cv. Mopan)

ABSTRACT:  The Mopan persimmon ( Diospyros kaki L. cv. Mopan) is the major cultivar of astringent persimmon in northern China. This study investigates the radical scavenging activity against ABTS and DPPH radical, and the content of total and individual phenolics (catechin, epicatechin, epigallocatechin, chlorogenic acid, caffeic acid, and gallic acid) with apple, grape, and tomato as controls. The radical scavenging activities against ABTS and DPPH radicals of the Mopan persimmon are 23.575 and 22.597 μm trolox eq/g f.w., respectively. These findings suggest that the Mopan persimmon's antioxidant activity is significantly ( P < 0.05) stronger than that of reference materials. The Mopan persimmon showed the highest content of total phenolics among the 4 materials tested. Significant correlations ( R ²= 0.993, P < 0.05, ABTS radical; R ²= 0.980, P < 0.05, DPPH radical) are found between the total phenolics and the radical scavenging activities. The total content of these 6 kinds of phenolics (catechin, epicatechin, epigallocatechin, chlorogenic acid, caffeic acid, and gallic acid) is significantly correlated ( R ²= 0.831, P < 0.05, ABTS radical; R ²= 0.745, P < 0.05, DPPH radical) with the individual radical scavenging activity of the 4 materials, although the total content of the 6 phenolics accounts for no more than 20% of the total phenolics in the Mopan persimmon. Gallic acid exhibits the strongest antioxidant activity in all 6 kinds of phenolics and its content is the largest in the Mopan persimmon, presumably being responsible for its much higher antioxidant activity as compared to apple, grape, and tomato.     

全叶青兰提取物抗氧化活性的研究

以全叶青兰经超临界CO2萃取后的萃取物为原料,采用乙醇提取后,根据极性差异经乙醚、乙酸乙酯和正丁醇依次萃取,对所得提取物的抗氧化活性进行了研究。结果表明,3种提取物对DPPH自由基和羟基自由基均具有比较强的抗氧化活性。其清除DPPH自由基的能力比较接近,而对羟基自由基的清除能力三者差异较大。其中,乙酸乙酯和乙醚提取物清除羟基自由基的半数清除率要明显小于同等条件下的对照品芦丁和BHT的清除浓度,正丁醇提取物清除DPPH自由基的半数清除率的浓度明显要小于清除羟基自由基的浓度,乙酸乙酯萃取物和乙醚萃取物在两个体系内的差异较小。     

A Comparative Study on the Various In Vitro Assays of Active Oxygen Scavenging Activity in Foods

ABSTRACT: Various in vitro assays of active oxygen-scavenging activity in foods were compared by evaluating the activity of 13 food phenolic compounds and Trolox. 1,1-Diphenyl-2-picrylhydrazyl (DPPH)-HPLC and liposome oxidation methods were sensitive for these compounds, while deoxyribose oxidation and Randox kit methods were less sensitive. The deoxyguanosine oxidation method could not determine the activity since food polyphenols were pro-oxidative in this assay. Among these assays, the DPPH-HPLC method was shown to be the best since the liposome oxidation method is affected more by the structure of phenolic compounds than the DPPH-HPLC method.     

Biological screening of 100 plant extracts for cosmetic use (II): anti-oxidative activity and free radical scavenging activity

Methanol aqueous extracts of 100 plants were screened for anti-oxidative activity using Fenton's reagent/ethyl linoleate system and for free radical scavenging activity using the 1,1-diphenyl-2-picryl hydrazyl free radical generating system. The results suggest that 14 plants - Alpinia officinarum, Areca catechu, Brassica alba, Cannabis sativa, Curcuma longa, Curcuma aromatica, Eugenia caryophyllata, Evodia officinalis, Paeonia suffruticosa, Rhaphanus sativus, Rheum palmatum, Rhus verniciflua, Trapa bispinosa, Zanthoxylum piperitum - may be potential sources of anti-oxidants. Eight plants - Citrus aurantium, Cornus officinalis, Gleditsia japonica, Lindera strychnifolia, Phragmites communis, Prunus mume, Schizandra chinensis, Terminalia chebula - may be the potential source of free radical scavengers from natural plant.     

绿茶有效成分分离及其对自由基的清除能力

对绿茶水提取物及提取的茶多酚的羟自由基清除能力进行评价,结果显示提纯的茶多酚（茶多酚浓度为２７．３９１ｍｇ／ｍｌ）对羟自由基清除能力高于绿茶水提取物（茶多酚浓度为２７．３９１ｍｇ／ｍｌ）,     

紫苏籽皮提取物的自由基清除能力及抗癌活性

探讨紫苏籽皮提取物(PSCE)的体外自由基清除能力及其抗癌活性。结果表明,以DPPH自由基和羟基自由基清除实验检测自由基清除能力。MTT法和平板克隆形成实验分别检测体外抗癌活性。PSCE具有较好的自由基清除能力,对DPPH自由基和羟基自由基的半清除剂量(IC50)分别为105.53μg/mL和269.65μg/mL。同时,PSCE对A375SM人黑色素瘤细胞的增殖抑制作用呈浓度和时间依赖关系。     

秦皮抗氧化成分的分离及其活性研究

用95%乙醇提取了秦皮中具有抗氧化活性的物质,并从中依次分离出七叶内酯、七叶甙,然后采用DPPH分析法研究了秦皮乙醇提取物及其主要成分七叶内酯、七叶甙对DPPH自由基的清除能力。结果显示,与合成抗氧化剂BHT比较,它们都有很强的自由基清除能力,其中七叶内酯对自由基的清除作用最强,秦皮乙醇提取物次之,七叶甙最弱;而且它们对自由基的清除能力与浓度和时间有关,浓度越大,抗氧化物加入时间越长,对自由基的清除能力就越强。     

Radical Scavenging Capacity and Antioxidant Activity of the E Vitamer Fraction in Rice Bran

ABSTRACT: Radical scavenging capacity and antioxidant activity of an E vitamer fraction from rice bran were investigated. The E vitamer fraction was prepared by a liquid-liquid extraction method. The free radical scavenging capacity of the E vitamer fraction was measured by the 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) method at the concentration range of 2.5 to 640 ppm, whereas the antioxidant activities were measured by both the reducing power and ferric thiocyanate (FTC) methods at different concentrations (0, 2.5, 10, 40, and 160 ppm). Radical scavenging capacity of the fraction was effective up to 160 ppm, then remained stable. Also, at a concentration of 160 ppm, it was highly effective in inhibiting linoleic acid peroxidation. Similarly, superoxide scavenging and antioxidant activities of the E vitamer fraction were compared with those of the synthetic phenol compounds. Results showed that with a concentration of the E vitamer fraction at 160 ppm, the antioxidant activity was comparable to both butylated hydroxytoluene (BHT, 160 ppm) and butylated hydroxyanisole (BHA, 160 ppm). No significant differences (P > 0.05) were found among them. The E vitamer fraction may be a good substitute for the synthetic phenol antioxidants currently used in industry because the former is more natural and comparatively effective in its radical scavenging capacity and antioxidant activity.     

Copper(II)-mediated biomimetic oxidation of quercetin: generation of a naturally occurring oxidation product and evaluation of its in vitro antioxidant properties

Quercetin was oxidized with CuSO₄ in aqueous acetonitrile, a reaction that has been previously shown to generate products that were detected in polyphenol oxidase and peroxidase-catalysed oxidation of quercetin. The major oxidation product was isolated and characterized by means of ¹H-NMR and LC-MS, as 2-(3,4-dihydroxybenzoyl)-2,4,6-trihydroxybenzofuran-3(2H)-one. This compound is a natural polyphenol reported to occur in the outer dry layers of onion bulbs. Its in vitro antioxidant properties were evaluated in comparison with the parent molecule and other natural polyphenols, employing three representative tests and the alterations in the activity observed were discussed on the basis of structure–activity relationships.     

紫苏提取物体外清除自由基能力的研究

以紫苏茎、叶为研究对象,采用不同溶剂获取各种提取物,用茶多酚、维生素E、TBHQ作为对照,采用DPPH自由基体系、烷基自由基引发的亚油酸氧化体系、超氧阴离子自由基体系、羟基自由基体系,研究各种提取物对不同自由基的清除作用。结果表明,提取物对四种自由基均有清除作用,其清除效果依次为羟基自由基>DPPH自由基>烷基自由基>超氧阴离子自由基。紫苏茎、叶的95％乙醇(v/v)与碱水混合物提取物(8:2v/v)的总黄酮得率最高,紫苏叶提取物的抗氧化性强于紫苏茎提取物。