金樱子多糖的抗氧化作用

目的：探讨金樱子多糖(PRL)体外抗氧化作用。方法：邻苯三酚自氧化法测定PRL清除超氧阴离子自由基效果;比色法测定PRL对羟自由基诱导红细胞溶血、脂质过氧化反应的影响。结果：PRL能显著清除超氧阴离子自由基、押制羟自由基对细胞膜的破坏而引起的溶血和脂质过氧化产物的形成。结论：PRL具有显著的抗氧化作用。     

冬葵果多糖的抗氧化作用研究

研究冬葵果多糖(Fructus Malvae polysaccharides,FMP)对氧自由基的清除作用及对脂质过氧化的抑制作用。采用分光光度法测定FMP清除Fenton体系产生的羟自由基(.OH)、邻苯三酚自氧化体系产生的超氧阴离子自由基(O2-.)的能力及评价对Fe(Ⅱ)-H2O2体系(.OH)诱导的脂质过氧化终产物丙二醛(MDA)的抑制作用。结果显示,在化学模拟体系中,冬葵果多糖对.OH具有很强的清除作用,与VC比较达到显著水平(P<0.01),对O2-.的清除能力与VC相当。在体外,多糖浓度达到1.72 mg/mL可明显降低MDA的含量,与空白液比较达到显著水平(P<0.01)。以上结果表明,FMP具有明显的抗氧化活性。     

黄伞胞外多糖抗自由基作用的研究

目的:以乙醇沉淀的黄伞发酵浓缩液得到的胞外多糖为研究对象,检验其对自由基的清除作用。方法:采用电子顺磁共振(EPR)波谱仪检测黄伞胞外多糖清除羟自由基OH.和超氧阴离子自由基O2-.的作用。结果:在样品浓度均为100mg/mL的条件下,利用Fenton反应体系,黄伞胞外多糖对羟自由基OH.的清除率仅为38.5%;而利用次黄嘌呤-黄嘌呤氧化酶体系,黄伞胞外多糖对超氧阴离子自由基O2-.的清除率可达到80.6%。结论:黄伞胞外多糖在体外对自由基有一定的清除作用且其对超氧阴离子自由基O2-.的清除作用明显优于对羟自由基OH.的清除作用。     

家蝇幼虫提取物清除氧自由基的作用

探讨了家蝇Musca domesticaL.幼虫提取物对氧自由基的清除作用。采用脱氧核糖-铁体系和邻苯三酚自氧化体系分别测定了不同浓度的提取物对羟自由基和超氧阴离子自由基的清除率,同时采用H2O2氧化体系测定了提取物的抗氧化值。结果显示家蝇幼虫提取物对羟自由基和超氧阴离子自由基的IC50分别为1.93 mg/mL和3.26 mg/mL;浓度为0.5%的提取物的抗氧化值为9.01 mg/g,为同浓度维生素C抗氧化值的1.29倍。     

沙棘茶水溶性多糖抗氧化活性的研究

通过还原力、清除超氧阴离子自由基、清除羟自由基和抑制H2O2诱导红细胞氧化溶血实验来评价沙棘茶水溶性多糖(WPHT)体外抗氧化能力,并与Vc进行了比较.结果表明,WPHT具有较强的还原能力,对O-·2和·OH具有较强的清除作用,IC50分别为:394 μg/mL、182 μg/mL;对H2O2诱导红细胞氧化溶血及MDA生成有很强的抑制作用,IC50分别为:221 μg/mL、202 μg/mL.说明WPHT在一定浓度范围内具有较强的抗氧化能力.     

黄鳝清除氧自由基作用的研究

采用化学发光法建立四个活性氧体外模型分析黄鳝粘液、血液、粗多糖清除氧自由基和抑制脂质过氧化作用。结果表明:黄鳝粘液、血液和粗多糖具有清除超氧阴离子自由基(O2·)、羟自由基(·OH)、过氧化氢(H2O2)和抑制脂质过氧化(LPO)作用。清除O2·的IC50分别为5.10±2.68μg/mL、3.62±1.56μg/mL、7.19±1.19μg/mL;清除·OH的IC50分别为5.86±1.54μg/mL、3.36±1.36μg/mL、7.93±0.50μg/mL;清除H2O2的IC50分别为6.91±1.29μg/mL、5.92±0.39μg/mL、8.21±0.61μg/mL;抑制LPO的IC50分别为8.11±0.83μg/mL、6.90±0.51μg/mL、7.62±1.01μg/mL。提示黄鳝血液清除氧自由基作用最明显,粘液次之,最弱为粗多糖。     

朱砂七粗多糖的提取及生物活性的研究

首次从朱砂七中提取粗多糖(PCCP),研究了PCCP对.OH自由基、O2-.自由基和DPPH.自由基的清除能力以及抗脂质过氧化能力,选用人肝癌细胞HepG2,经MTT染色法研究其体外抗肿瘤活性。结果显示,PC-CP的浓度在8.48 mg/mL时,对.OH、O2-.和DPPH.的清除率分别达到了52.3%、54.7%和38.3%;PCCP的浓度在8.48 mg/mL时,对脂质过氧化的抑制率达到了62.0%;PCCP的浓度在277.78μg/mL时,对人肝癌细胞HepG2的抑制率达到了42.6%,表明PCCP具有一定的体外抗氧化能力和体外抗肿瘤活性。     

南瓜多糖衍生物的制备及其抗氧化研究

对超声辅助法提取的南瓜粗多糖,进行化学改性得到了硫酸化南瓜多糖和羧甲基南瓜多糖。用邻苯三酚自氧化法检测对超氧阴离子自由基的清除作用,用邻二氮菲-金属铁离子-H2O2体系检测对羟自由基的清除作用。结果表明,南瓜多糖对超氧阴离子自由基无抑制作用,经化学改性后的羧甲基南瓜多糖和硫酸化南瓜多糖对超氧阴离子自由基有明显抑制作用,最大清除率达44％和41．67％。以上3种多糖均能有效清除·OH,随着浓度的增加清除作用加强,最大清除率可达46．49％,22．61％和42．35％0。结果显示,经化学改性后的南瓜多糖有较强的抗氧化作用。     

“黑美人”土豆色素体外抗氧化性研究

采用普鲁士蓝法、DPPH清除体系、H2O2/Fe2+/水杨酸检测体系、亚硝基清除体系、卵黄脂蛋白不饱和脂肪酸(PUFA)过氧化体系、邻苯三酚自氧化法研究了黑美人土豆色素的体外抗氧化活性,并同VC进行了比较。结果表明,黑美人土豆色素对几种自由基均有不同的清除作用,其中黑美人土豆色素的还原力、抗脂质过氧化能力、清除羟基自由基、亚硝基、超氧阴离子自由基(O2-.)和DPPH自由基的能力均高于VC。该结果显示,黑美人土豆色素是一种较好的天然自由基清除剂,可以作为绿色食品用于人们的日常饮食,有较大的开发利用潜能。     

葎草多糖含量测定及其抗氧化性研究

对8月和10月采集的葎草全草、嫩头、叶和茎中多糖含量进行测定,并对各部位提取纯化的多糖进行体外抗氧化作用研究。结果表明,8月份嫩头中多糖含量最高,达到(42.897±2.996)mg/g;浓度为5mg/mL的各部位葎草多糖溶液,对Fenton反应生成的羟自由基具有较强的清除能力,达85.15%～98.52%;对邻苯三酚自氧化法产生的超氧阴离子自由基也有较好的抑制能力,达57.15%～67.54%。葎草多糖对羟自由基和超氧阴离子自由基具有较高的清除能力。     

Antioxidative and cytoprotective effects of Artemisia capillaris fractions

The antioxidant effects of Artemisia capillaris fractions against reactive oxygen species (ROS) were evaluated by measuring scavenging activities against 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, superoxide (O_2(-)), hydroxyl (HO.) and nitric oxide (NO.) radical. Among five solvent fractions, ethyl acetate fraction showed the highest total polyphenol and total flavonoid contents as 648.75 and 89.09 microg/mg, respectively. Also, the ethyl acetate fraction showed the highest scavenging activity; the 50% inhibitory concentration (IC50, microg/mg) value for DPPH, O_2(-), HO. and NO. radical scavenging were 4.76, 31.54, 69.34 and 74.63, respectively. Additionally, the highest inhibition of rat liver microsomal lipid peroxidation was observed by ethyl acetate fraction. Except for free radical-mediated protein damage, ethyl acetate fraction showed the highest scavenging activity. The effect of Artemisia capillaris fractions on cell viability and DNA damage induced by H2O2 in Raw 264.7 cell were also evaluated by MTT and comet assay, respectively. The protective effect of ethyl acetate fraction, as indicated by cell viability increasing 71% and DNA breakage decreasing 51% as compared with H2O2-treated positive control. These results suggest that ethyl acetate fraction possess significant ROS scavenging and protective effect against oxidative DNA damage.     

The antioxidant activity of glucosamine hydrochloride in vitro

The antioxidant potency of chitin derivative-glucosamine hydrochloride was investigated employing various established in vitro systems, such as superoxide (O2*-)/hydroxyl (*OH)-radical scavenging, reducing power, and ferrous ion chelating potency. As expected, we obtained several satisfying results, as follows: first, glucosamine hydrochloride had pronounced scavenging effect on superoxide radical. For example, the O2*- scavenging activity of glucosamine hydrochloride was 83.74% at 0.8 mg/mL. Second, the *OH scavenging activity of glucosamine hydrochloride was also strong and was about 54.89% at 3.2 mg/mL. Third, the reducing power of glucosamine hydrochloride was more pronounced. The reducing power of glucosamine hydrochloride was 0.632 at 0.75 mg/mL. However, ferrous ion-chelating potency was soft. Furthermore, ferrous ion-chelating potency, the scavenging rate of radical, and the reducing power of glucosamine hydrochloride increased with their increasing concentration, and they were concentration dependent. The multiple antioxidant activity of glucosamine hydrochloride was evident as it showed considerable reducing power, superoxide/hydroxyl-radical scavenging ability. These in vitro results suggest the possibility that glucosamine hydrochloride could be effectively employed as an ingredient in health or functional food, to alleviate oxidative stress.     

Antioxidant properties and protective effects of a standardized extract of Hypericum perforatum on hydrogen peroxide-induced oxidative damage in PC12 cells

Free radical scavenging and antioxidant activities of a standardized extract of Hypericum perforatum (SHP) were examined for inhibition of lipid peroxidation, for hydroxyl radical scavenging activity and interaction with 1,1-diphenyl-2-picrylhydrazyl stable free radical (DPPH). Concentrations between 1 and 50 microg/ml of SHP effectively inhibited lipid peroxidation of rat brain cortex mitochondria induced by Fe2+/ascorbate or NADPH system. The results showed that SHP scavenged DPPH radical in a dose-dependent manner and also presented inhibitory effects on the activity of xanthine oxidase. In contrast, hydroxyl radical scavenging occurs at high doses. The protective effect of the standardized extract against H2O2-induced oxidative damage on the pheochromocytoma cell line PC 12 was investigated by measuring cell viability via 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), lactate dehydrogenase (LDH) assays, caspase-3-enzyme activity and accumulation of reactive oxygen species [2',7'-dichlorofluorescin (DCF) assay]. Following 8-h cell exposure to H2O2 (300 microM), a marked reduction in cell survival was observed, which was significantly prevented by SHP (pre-incubated for 24 h) at 1-100 microg/ml. In a separate experiment, different concentrations of the standardized extract (0.1-100 microg/ml) also attenuated the increase in caspase-3 activity and suppressed the H2O2 -induced reactive oxygen species generation. Taken together, these results suggest that SHP shows relevant antioxidant activity both in vitro and in a cell system, by means of inhibiting free radical generation and lipid peroxidation.     

蛹虫草无性型菌丝体提取液体外抗氧化活性研究

分别测定了蛹虫草无性型菌丝体不同溶剂提取液在不同抗氧化模型中的抗氧化作用。结果表明,各种提取液对二苯基苦味酰基苯肼自由基(·DPPH)和羟自由基(·OH)均有显著的清除作用:在50mg/mL时,去离子水、70%乙醇和70%丙酮提取物对DPPH自由基的清除率分别为89.2%、83.6%和75.9%;70%乙醇提取物在30mg/mL时对·OH自由基的清除率达到100%;在50mg/mL时70%丙酮和去离子水提取物的·OH自由基清除率分别为95.6%和89.6%。在一定浓度下,各提取液对邻苯三酚自氧化也均有抑制作用;不同溶剂提取物的还原能力强弱为:70%乙醇>去离子水>70%丙酮。各种提取物的抗氧化组分不同,提取物浓度与抗氧化性成正相关。     

沙棘果皮多糖清除氧自由基的活性研究

沙棘(Hippophae rhamnosides)果皮经80℃恒温水浴提取, 乙醇沉淀得粗多糖。Sevag法去蛋白,经50%和70%乙醇分级, 得3种级分沙棘多糖H1、H2和H3; 以Fenton 反应, 即H2O2/Fe2+/水杨酸为.OH产生和检测体系; 以邻苯三酚/EDTA/Tris-HCl为O2 -. 产生体系, 对沙棘多糖H1、H2和H3进行抗氧自由基活 性研究。结果表明, 沙棘多糖对.OH和O2 -. 有较显著的清除能力。不同级分多糖H1、H2和H3浓度达200mg.mL-1时, 对.OH的清除率分别为44.9%、49.0%和26.4%, 抗O2-. 活性分别为36.9%,15.4%和23.1%。多糖质量浓度增大时,两种自由基清除率增加, 且呈量效关系。     

Antioxidant activities of cultured Armillariella mellea

This study aimed to evaluate the antioxidant activities of a cultured medicinal fungus--Armillariella mellea (Vahl. ex Fr.) Karst. (AM). Three antioxidant assay systems, namely cytochrome c, xanthine oxidase inhibition and FeCl2-ascorbic acid stimulated lipid peroxidation in rat tissue homogenate tests, were used. Total flavonoid and phenol contents of AM extracts were also analyzed. Results showed that both aqueous (AM-H2O) and ethanolic (AM-EtOH) extracts of solid state cultured AM showed antioxidant activities in a concentration-dependent manner. At concentrations 1-100 microg/ml, the free radical scavenging activity was 73.7-92.1% for AM-H2O, and 60.0-90.8% for AM-EtOH. These extracts also showed an inhibitory effect on xanthine oxidase activity, but with a lesser potency (IC50 - 9.17 microg/ml for AM-H2O and 7.48 microg/ml for AM-EtOH). In general, AM-H2O showed a stronger anti-lipid peroxidation activity on different rat's tissues than AM-EtOH. However, both AM extracts displayed a weak inhibitory effect on lipid peroxidation in plasma. Interestingly, the anti-lipid peroxidation activity of AM-H2O (IC50 - 6.66 microg/ml) in brain homogenate was as good as alpha-tocopherol (IC50 - 5.42 microg/ml). AM-H2O (80.0 mg/g) possessed a significant higher concentration of total flavonoids than AM-EtOH (30.0 mg/g), whereas no difference was noted in the total phenol content between these two extracts. These results conclude that AM extracts possess potent free radical scavenging and anti-lipid peroxidation activities, especially the AM-H20 in the brain homogenate.     

Free radical scavenging and antioxidant effects of lactate ion: an in vitro study.

Divergent literature data are found concerning the effect of lactate on free radical production during exercise. To clarify this point, we tested the pro- or antioxidant effect of lactate ion in vitro at different concentrations using three methods: 1) electron paramagnetic resonance (EPR) was used to study the scavenging ability of lactate toward the superoxide aion (O(2)(-).) and hydroxyl radical (.OH); 2) linoleic acid micelles were employed to investigate the lipid radical scavenging capacity of lactate; and 3) primary rat hepatocyte culture was used to study the inhibition of membrane lipid peroxidation by lactate. EPR experiments exhibited scavenging activities of lactate toward both O(2)(-). and.OH; lactate was also able to inhibit lipid peroxidation of hepatocyte culture. Both effects of lactate were concentration dependent. However, no inhibition of lipid peroxidation by lactate was observed in the micelle model. These results suggested that lactate ion may prevent lipid peroxidation by scavenging free radicals such as O(2)(-). and.OH but not lipid radicals. Thus lactate ion might be considered as a potential antioxidant agent.     

Free-radical scavenging by Ouratea parviflora in experimentally-induced liver injuries

The antioxidant potential of crude extracts and fractions from leaves of Ouratea parviflora, a Brazilian medicinal plant used for the treatment of inflammatory diseases, was investigated in vitro through the scavenging of radicals 2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH), hydroxyl radical (HO*), superoxide anion (O2*-), and lipid peroxidation in rat liver homogenate. The crude extract (CEOP) and hydro-alcoholic fraction (OP4) showed strong inhibitory activity toward lipid peroxidation induced by tert-butyl peroxide (IC50 = 2.3 +/- 0.2 and 1.9 +/- 0.1 microg/ml, respectively). The same products exhibited a strong concentration-dependent inhibition of deoxyribose oxidation (14.9 +/- 0.2 and 0.2 +/- 0.1 microg/ml, respectively), and also showed a considerable antioxidant activity against O2*- (87.3 +/- 0.1 and 73.1 +/- 0.4 microg/ml, respectively) and DPPH radicals (55.4 +/- 0.3 and 38.3 +/- 0.4 microg/ml, respectively). The protective effects of CEOP and OP4 were also studied in mouse liver. CCl4 significantly increased (by 90%) levels of lipid hydroperoxides, carbonyl protein content (64%), DNA damage index (133%), aspartate aminotransferase (261%), alanine aminotransferase (212%), catalase activity (23%), and also caused a decrease of 60% in GSH content. The results showed that CEOP and OP4 exerted cytoprotective effects against oxidative injury caused by CCl4 in rat liver, probably related to the antioxidant activity showed by the in vitro free radical scavenging property.     

库克诺你果汁提取物体外清除自由基及抗氧化活性研究

本文对诺你果汁多糖、乙醇溶出物和乙酸乙酯萃取物体外对超氧阴离子(O2·)、羟自由基(·OH)、DPPH和脂质过氧化(LPO)的抑制作用进行了研究。超氧阴离子(O2·)由邻苯三酚自氧化产生;羟自由基(·OH)由Fenton反应产生;利用Fe2 诱发卵黄脂蛋白产生丙二醛(MDA),TBA法测定。所有测定均为分光光度法。结果表明,与已知抗氧化剂L抗坏血酸相比,乙醇溶出物和乙酸乙酯萃取物均有明显的捕捉自由基和抗氧化能力,而多糖捕捉自由基和抗氧化能力很低,且对O2·没有抑制作用,反而会增加其生成速度。     

Antioxidant activity of novel chitin derivative

Novel water-soluble chitin derivative was prepared by chemical modification to evaluate antioxidant activities by free radical scavenging potential using electron spin resonance spin trapping technique. Aminoethyl-chitin (AEC) exhibited free radical scavenging activities against 1,1-diphenyl-2-picrylhydrazyl (DPPH), hydroxyl, superoxide, and peroxyl radicals. AEC quenched DPPH and peroxyl radical over 55% and 59% at 4mg/mL, and also suppressed superoixde radical over 58% at 2mg/mL. Especially, AEC was more active against hydroxyl radical, and scavenging ratio was 92.2% at 0.12mg/mL. These results suggested that free amino group in the -CH(2)CH(2)NH(2) plays an important role in the free radical scavenging activity. In addition, cytotoxic effect of AEC was assessed using human lung fibroblast (MRC-5) cell line, and AEC showed less toxic against MRC-5.