菊苣酸对活性氧诱导脂质和DNA氧化损伤的影响

目的：探讨菊苣酸对脂质和DNA氧化损伤的影响。方法：通过Cu2+/H2O2和2,2’-偶氮二（2-甲基丙基咪） 二盐酸盐（2,2’-azobis(2-amidinopropane)dihydrochloride,AAPH）分别诱导小鼠肝匀浆和脑匀浆、鲱鱼精DNA和 pBR322质粒DNA,建立脂质和DNA氧化损伤模型,研究菊苣酸对脂质和DNA氧化损伤的影响;通过硫代巴比妥酸 法检测脂质过氧化程度和鲱鱼精DNA氧化损伤程度;采用琼脂糖凝胶电泳检测pBR322质粒DNA氧化损伤程度。结 果：在Cu2+/H2O2诱导体系中,菊苣酸在一定浓度范围内对脂质和DNA具有较强的保护作用,但高浓度菊苣酸对小 鼠肝匀浆和脑匀浆以及鲱鱼精DNA的保护作用减弱,100 μmol/L菊苣酸对pBR322质粒DNA表现出促氧化作用;在 AAPH诱导体系中,菊苣酸在实验浓度范围内能明显抑制脂质和DNA的氧化损伤。结论：菊苣酸对脂质和DNA具有 明显保护作用,但高浓度菊苣酸对羟自由基诱导脂质和DNA氧化损伤具有促进作用。     

五味子蜂花粉不同萃取物对小鼠肝脏脂质过氧化及DNA氧化损伤的作用

五味子蜂花粉具有强抗氧化活性,为了探究其抗氧化活性成分分布,本研究采用体积分数75%乙醇溶液对五味子蜂花粉进行浸提,分别用石油醚、乙酸乙酯和正丁醇进行萃取,测定不同萃取物的活性成分和体外抗氧化活性,研究其对小鼠肝脏脂质过氧化的抑制作用和对·OH诱导的pBR322质粒DNA氧化损伤的保护作用。结果表明,五味子蜂花粉不同萃取物抗氧化活性及其对小鼠肝脏脂质过氧化的抑制作用和对DNA氧化损伤的保护作用均存在显著差异（P＜0.05）,其顺序为：正丁醇萃取物＞乙酸乙酯萃取物＞石油醚萃取物。正丁醇萃取物的总酚含量最高,为26.11 g/100 g,总黄酮含量为27.90 g/100 g;有很强的Fe2＋络合能力、还原力和对1,1-二苯基-2-三硝基苯肼自由基的清除能力;0.2 mg/mL正丁醇萃取物对小鼠肝脏脂质过氧化的抑制率可达85%以上。本研究为进一步分离纯化五味子蜂花粉高抗氧化活性酚类物质提供依据,同时为抗氧化功能食品的开发提供参考。     

核桃叶多糖对脂质和DNA氧化损伤的作用研究

采用 Cu2+/H2O2和 2,2′-偶氮二（2-甲基丙基咪）二盐酸盐[2,2′-azobis（2-methylpropionamidine）dihydrochloride,AAPH]两种不同的反应体系,分别诱导SD大鼠肝匀浆和脑匀浆、卵磷脂、亚油酸以及pBR322质粒DNA产生氧化损伤,建立脂质和DNA氧化损伤模型,考察核桃叶多糖对脂质和DNA氧化损伤的作用。通过硫代巴比妥酸法检测脂质过氧化程度;利用琼脂糖凝胶电泳检测pBR322质粒DNA氧化损伤程度。结果表明：核桃叶多糖在一定的浓度范围内对Cu2+/H2O2诱导的脂质和DNA氧化损伤有明显的保护作用;在AAPH诱导体系中,核桃叶多糖能明显抑制脂质和DNA氧化损伤,且呈浓度依赖性。     

枸杞蜜的抗氧化活性及其对DNA氧化损伤的保护作用

以青海枸杞蜜为研究对象,在测定其总酚、总黄酮含量和抗氧化活性基础上,采用彗星电泳技术,研究了枸杞蜜对羟基自由基诱导的小鼠淋巴细胞DNA氧化损伤的保护作用。结果表明,枸杞蜜不仅能够有效地清除自由基,而且具有较强的抗氧化活性,枸杞蜜的抗氧化活性与其总酚含量有关(p<0.05),Fe2+络合力与其总黄酮含量相关(p<0.01)。彗星电泳结果表明,枸杞蜜能够显著降低羟基自由基诱导的小鼠淋巴细胞DNA的氧化损伤,与模型组相比,加入枸杞蜜的保护组彗星尾部DNA比例、尾矩(TM)和Olive尾矩(OTM)显著降低(p<0.05),且与枸杞蜜浓度存在明显的剂量-效应关系,线性回归方程决定系数依次为:R2=0.9775,R2=0.9341,R2=0.9425。本文的研究结果将为枸杞蜜功能性食品的开发利用提供依据。     

啤酒花多酚提取物体内外抗氧化活性研究

从酿造废酒花（Humulus lupulus L.）中提取制备一种高纯度（总多酚含量为88.7%）的酒花多酚提取物（hop polyphenol extract,HPE）,测定其酚类组成成分与体内外抗氧化活性。结果表明：HPE中55%以上的多酚物质是原花青素,28%以上的多酚物质是黄酮苷类。在体外,HPE能有效清除活性氧自由基,显著抑制Cu2+-VC诱导的DNA氧化断裂损伤。在体内,口服200～800 mg/kg（以体质量计）多酚剂量的HPE可显著抑制因溴代苯诱导的小鼠肝脏超氧化物歧化酶和谷胱甘肽过氧化物酶活性的降低,也可降低溴代苯氧化应激小鼠肝脏的硫代巴比妥酸产物含量。结论：膳食摄入HPE可提供体内外抗氧化损伤的保护作用,酒花多酚的体内外抗氧化效果均优于同质量浓度的绿茶多酚。     

茜草精油抗氧化及DNA损伤保护效果

以水蒸气蒸馏法提取茜草精油,以天然和合成的抗氧化剂为对照,用5种不同的抗氧化体系(DPPH、·OH和O~(2)-·自由基,还原力和总抗氧化能力)检测评价茜草精油的抗氧化活性;并以·OH自由基介导的p BR322质粒损伤模型进行了精油的DNA损伤保护效果的评价。结果表明:精油表现出在不同体系中以剂量依赖方式的不同程度的功效,并且对清除DPPH和·OH自由基活性较强。精油对·OH自由基介导的p BR322质粒损伤的保护效果可能源于精油对·OH自由基较好的清除作用。     

菊苣酸对蛋白质氧化损伤的作用

目的：评价菊苣酸对自由基诱导蛋白质氧化损伤的影响。方法：采用Cu2＋/H2O2和2,2’-偶氮二（2-甲基丙 基咪）二盐酸盐（2,2’-azobis(2-methylpropionamidine)dihydrochloride,AAPH）两种不同的自由基诱导体系,分别 诱导牛血清白蛋白（bovine serum albumin,BSA）、小鼠肝脏蛋白和脑蛋白氧化损伤,研究菊苣酸对蛋白氧化损 伤的影响;通过十二烷基硫酸钠-聚丙烯酰胺凝胶电泳和蛋白免疫印迹法检测蛋白氧化损伤程度。结果：菊苣酸在 100～1 000 μmol/L浓度范围内能够抑制Cu2＋/H2O2诱导的BSA氧化损伤;低浓度菊苣酸对Cu2＋/H2O2诱导的小鼠肝脏 蛋白和脑蛋白氧化损伤具有保护作用,但在高浓度时表现出促氧化作用;在AAPH诱导体系中,菊苣酸对3 种蛋白 模型均具有保护作用,且菊苣酸浓度越高保护效果越好。结论：在Cu2+/H2O2和AAPH两种诱导体系中,菊苣酸对蛋 白质氧化损伤表现出不同的作用效果。     

红枣多糖对D-半乳糖诱导衰老小鼠肝脏抗氧化活性的研究

研究红枣多糖对D-半乳糖（D-galactose,D-gal）诱导衰老小鼠肝脏抗氧化活性。用水提醇沉法提取红枣多糖，以不同剂量（200、400、800 mg/kg）的红枣多糖灌胃实验小鼠，以生理盐水和维生素C(vitamin C,Vc)作为对照，对各组小鼠脏器指数，肝脏、血清中的抗氧化酶活性，肝脏的组织结构进行测定。800 mg/kg红枣多糖剂量组可以缓解D-gal诱导的衰老小鼠脏器指数的下降，提高肝脏组织中超氧化物歧化酶（superoxide dismutase,SOD）、谷胱甘肽过氧化物酶（glutathione peroxidase,GSH-Px）、过氧化氢酶（catalase,CAT）和血清中SOD、GSH-Px的活性，降低丙氨酸氨基转移酶（alanine aminotransferase,ALT）、天门冬氨酸氨基转移酶（aspartate aminotransferase,AST）的活性和丙二醛（malondialdehyde,MDA）含量，降低肝脏组织中脂滴空泡形成，有效保护肝脏组织的完整。800 mg/kg红枣多糖可以有效缓解D-gal诱导的小鼠肝脏氧化损伤。     

楮果总黄酮体外抗氧化及对CCl4致脑损伤小鼠的保护作用

目的:探讨楮果总黄酮体外抗氧化活性及对四氯化碳（carbon tetrachloride,CCl₄）致脑氧化损伤小鼠的保护作用。方法:通过体外模拟建立过氧化氢（hydrogen peroxide,H₂O₂）诱导红细胞溶血、肝、脑匀浆脂质过氧化、Fe2+-Vc诱导肝线粒体肿胀的生物膜实验体系和体外总抗氧化能力实验,研究楮果总黄酮的体外抗氧化活性。同时,建立CCl₄诱导小鼠脑组织氧化损伤模型,将60只昆明小鼠分为空白组、模型组、阳性对照组（水飞蓟素,0.2 g/kg）和楮果总黄酮各剂量（0.15、0.3、0.6 g/kg）组,灌胃给药,隔天腹腔注射CCl₄花生油溶液（体积比1:1）2 mL/kg造模,持续14 d。通过测定氧化应激参数丙二醛（malondialdehyde,MDA）、超氧化物歧化酶（superoxide dismutase,SOD）、谷胱甘肽（glutathione,GSH）、谷胱甘肽过氧化物酶（glutathione peroxidase,GSH-PX）和过氧化氢酶（catalase,CAT）水平并观察小鼠脑组织海马区病理学切片,评价观察楮果总黄酮在体内的抗氧化能力。结果:体外实验中,楮果总黄酮对小鼠红细胞溶血、肝、脑组织匀浆脂质过氧化和肝线粒体肿胀的抑制作用随浓度的增加而增强,其总抗氧化能力也随浓度的增大而增强。在CCl₄脑损伤模型中,楮果总黄酮可显著提高（P<0.05）小鼠脑组织SOD、GSH-PX、CAT活性和GSH水平,显著降低（P<0.05）MDA水平,且呈剂量依赖性,同时对小鼠海马神经元的病理学变化有改善作用。结论:楮果总黄酮具有较强体外抗氧化活性,并对CCl₄致小鼠脑组织氧化损伤表现出较好的保护作用,具有良好的体内抗氧化能力。     

Protective effect against oxidation of human low-density lipoprotein and plasmid DNA strand scission of Tamarind seed coat extract in vitro

Methanolic extract from seed coat of Thai Tamarindus indica L. containing polyphenol; procyanidins, (−)-epicatechin was studied in vitro for protective effect against Cu²⁺-induced human low-density lipoprotein (hLDL) oxidation and oxidative damage of plasmid DNA induced by Fenton reactant. LDL oxidation was monitored by formation of conjugated dienes, fluorescent products, protein carbonylation and thiobarbituric acid reactive substances (TBARS). Supercoiled DNA strand scission was evaluated by gel electrophoresis. The extract inhibited formation of all four products of oxidized LDL in a dose-dependent manner over 25-1000 ng/ml extracts. Furthermore, 1 mg/ml extract also protected supercoiled DNA strand in plasmid pBR322 against scission induced by Fenton-mediated hydroxyl radical similar to that found with reference antioxidant, 0.5 μg/ml Trolox. Thus, seed coat extract from Thai Tamarind shows antioxidant effects against in vitro Cu²⁺-mediated LDL oxidation and hydroxyl radical-induced supercoiled DNA damage. These results suggest that seed coat extract from Thai Tamarind may be useful for preventing LDL oxidation and DNA damage.     

Phenolic content,antioxidant potential and DNA damage protection of pearl millet (<Emphasis Type="Italic">Pennisetum glaucum</Emphasis>) cultivars of North Indian region

Total phenolic contents, condensed tannin content, antioxidant activity and DNA damage protection of twelve pearl millet cultivars from North Indian region were assayed. All pearl millet cultivars showed considerable amount of bioactive compounds with antioxidant potential. PUSA-415 showed the presence of maximum amount of extractable total phenolic content (7.32 mg GAE/g DWB), whereas HHB-223 cultivar depicted the highest amount of condensed tannin contents (138.45 mg CE/100 g DWB). Antioxidant activity was measured using different methods viz., DPPH, ABTS, FRAP, TAC and HFRSA. A clear correlation was observed between total phenolic content and antioxidant activity of different pearl millet cultivars. The extracts of all cultivars prevented the oxidative damage to plasmid DNA (pBR322) against DNA damaging Fenton’s reagent. However, cultivars PC-383, PUSA-415, PUSA-605, PC-612 and 841-B showed prominent DNA damage protection activity. The results of this study provide a scientific basis of the traditional use of pearl millet as a natural antioxidant mitigating DNA damage.     

Physicochemical properties,antioxidant activity and cellular protective effects of honeys from southern Africa

The southern Africa region is a region of unique floral biodiversity; this study was undertaken to address the limited knowledge regarding the physiochemical, antioxidant activity and the ability of these honeys to protect biomolecules and cells against oxidative damage. The physicochemical properties, total polyphenolic and flavonoid content (TPC and TFC), catalase and antioxidant activity (DPPH, TEAC, and ORAC assays) of 13 representative honey samples was determined. Biological and cellular protection was investigated using the erythrocyte haemolysis, the pBR322 plasmid, as well as the dichlorofluorescein diacetate (DCFH-DA) assays in SC-1 and Caco-2 cells. High TPC, TFC, catalase and antioxidant activity was obtained, and all honeys protected DNA, erythrocytes and cells in vitro. Colour, TPC, TFC and antioxidant activity correlated well but no correlation was seen between these parameters and catalase activity, biological and cellular effects. Nevertheless, honeys with high catalase activity and/or are dark in colour with high TPC, TFC and/or antioxidant activity did show the highest degree of biological and cellular protection.     

Synergistic effect of green tea polyphenols with trolox on free radical-induced oxidative DNA damage

The antioxidant effect of the principal polyphenolic components extracted from green tea leaves, namely (−)-epicatechin (EC), (−)-epigallocatechin (EGC), (−)-epicatechin gallate (ECG) and (−)-epigallocatechin gallate (EGCG), and their synergistic antioxidant effects with trolox against oxidative DNA damage were studied. The oxidative DNA damage was initiated by a water-soluble azo initiator, 2,2′-azobis (2-amidinopropane hydrochloride) (AAPH) and the ability of green tea polyphenols and/or trolox (a water-soluble analogue of α-tocopherol) to inhibit the oxidative damage of DNA was assessed, in vitro, by measuring the conversion of supercoiled pBR322 plasmid DNA to the open circular and linear forms. It was found that these green tea polyphenols could significantly inhibit the oxidative damage of DNA synergistically with trolox, with an activity sequence of EC = ECG > EGCG > EGC.     

Enzymatic production of bioactive protein hydrolysates from tuna liver: effects of enzymes and molecular weight on bioactivity

Tuna liver is fish by‐product, which is normally discarded and/or used as fish meal and animal feed because of poor functionality. In this study, we attempt to recover functional peptides from tuna liver protein by enzymatic hydrolysis using various proteases, and further hydrolysates were fractionated into four categories base on their molecular weight (MW) by ultrafiltration membranes. All fractionated hydrolysates produced by Alcalase, Neutrase and Protamex following Flavourzyme hydrolysis showed excellent antioxidant activities against DPPH, hydrogen peroxide and hydroxyl radical scavenging, and reducing power. Their bioactivity was dependent on treated enzymes, and antioxidant activities of fractions dependent on employing bioassay. Moreover, they confirmed antioxidant ability toward the protection effects on hydroxyl radical‐induced DNA damage by the measuring the conversion of supercoiled pBR322 plasmid DNA to the open circular form. In addition, all fractionated hydrolysates inhibited acetylcholinesterase activity, which is involved in Alzheimer’s diseases, and high MW fractions showed high AChE inhibition activity than those of low MW fractions.     

Phenolic profile and antioxidant properties of Polish honeys

The phenolic components of honeys have great participation in their nutritional value and antioxidant activity. Moreover, phenolic components are promising markers for the determination of botanical and geographical origin of honey. The purpose of the present work was to study the antioxidant activity and profiles of phenolic acids and flavonoids of honeys of various origins. The total phenolic content of honeys varied from 4.46 to 15.04 mg of gallic acid equivalents per 100 g of product and the total phenolic acid content determined chromatographically varied from 201.05 to 2089.08 μg per 100 g of product. Buckwheat honey exhibited the highest antioxidant activity and contained the highest total phenolic amount, whereas rape honey exhibited the lowest values in this respect. Moreover, the buckwheat honey contained the highest amount of phenolic acids. There were significant linear correlations between total phenolic content and antioxidant activity of honey extracts in the reaction with DPPH^? (1,1‐diphenyl‐2‐picrylhydrazyl) and ABTS^{? +} (2,2′‐azinobis‐(3‐ethylbenzothiazoline‐6‐sulfonic acid)) free radicals. In most samples, p‐coumaric acid was the dominant phenolic acid (39.1–677.2 μg per 100 g). The honeys also contained considerable amount of gallic acid (6.0–913.8 μg per 100 g). Among flavonoids naringenin was predominant in the most studied honey samples.     

Antioxidant activity of sugar molasses, including protective effect against DNA oxidative damage

ABSTRACT:  Extracts were obtained from molasses, a byproduct of the sugar industry, via a number of chromatographic steps. Their antioxidant capacity was studied, including the inhibitory effect upon DNA oxidative damage; the phenolic compound profile thereof was ascertained as well. Two extracts exhibited significant antioxidant features, expressed by their capacity to decolorize ABTS radical cation and to scavenge hydroxyl free radicals (via deoxyribose assay). Those 2 extracts also brought about protection against induced DNA oxidative damage (via decreasing DNA scission, as assessed by electrophoresis). The phenolic compounds syringic acid, p -hydroxybenzoic acid, vanillic acid, p -hydroxybenzaldehyde, and ferulic acid were positively identified and quantified.     

牛蒡根总黄酮抗氧化活性研究

以牛蒡根为材料,采用常规方法测定牛蒡根总黄酮的DPPH自由基清除能力、羟基自由基清除能力、总抗氧化能力、还原力、金属螯合能力、抗脂质过氧化能力和对DNA氧化损失的保护作用,同时测定了牛蒡根总黄酮的含量。结果表明,牛蒡根总黄酮的自由基清除能力、总抗氧化能力、金属螯合能力和还原力随浓度的增加而增强,且呈剂量依赖性相关,DPPH自由基清除能力的半数抑制浓度（IC50）为15.7mg/mL;对大鼠肝脂质过氧化产生的丙二醛（MDA）有较好的清除效果,IC50为34μg/mL;对K562细胞DNA氧化损伤具有保护作用。由此说明,牛蒡根为一种很好的天然抗氧化剂。