豌豆蛋白水解物体外及对HepG2细胞的抗氧化活性

为了全面评价豌豆蛋白水解物(pea protein hydrolysates, PPH)及其超滤分离组分的体外及细胞抗氧化能力，以豌豆蛋白为原料，采用碱性蛋白酶和复合蛋白酶协同水解制备PPH,然后超滤分级得到PPH1(分子质量<3 kDa)、PPH2(分子质量3～5 kDa)、PPH3(分子质量>5 kDa)3个组分，使用不同的化学方法研究PPH和超滤分离组分的抗氧化活性，从中选择抗氧化能力最高的组分进一步考察其细胞内自由基清除能力并用H₂O₂应激的HepG2细胞评估其对氧化应激的保护作用。结果表明，各组分中PPH1具有最高的体外化学抗氧化活性，其氨基酸组成分析表明，抗氧化功能氨基酸占比高；在实验设定浓度下，PPH1能够显著抑制H₂O₂应激损伤HepG2细胞内活性氧的积累，对细胞应激损伤有明显的保护作用。研究认为，PPH及其超滤分离组分具有良好的体外化学及细胞抗氧化活性，对H₂O₂应激的HepG2细胞具有保护作用，能够为其作为一种天然源抗氧化剂...     

莲壳多酚对T-BHP致HepG2氧化应激损伤的保护作用

目的：研究莲子壳多酚对叔丁基过氧化氢（tert-butylhydro-peroxide,T-BHP）诱导的HepG2氧化应激损伤的保护作用。方法：选取存活率接近50%的T-BHP浓度作为氧化损伤模型建立的浓度。以细胞活力、活性氧水平（reactive oxygen species,ROS）、丙二醛水平（malondialdehyde,MDA）、乳酸脱氢酶水平（Lactic dehydrogenase,LDH）、谷胱甘肽（Glutathione,GSH）水平及抗氧化酶相关基因表达量为评价指标,以茶多酚为阳性对照,评价不同浓度（2.5、5、7.5μg/mL）莲子壳多酚抗氧化应激活性水平。结果：当120μmol/L浓度的T-BHP造模4 h后,细胞存活率达49.18%±7.55%,符合模型构建要求,故选择120μmol/L为氧化损伤模型的建模浓度进行后续实验。莲子壳多酚能极显著抑制T-BHP造成的细胞存活率降低（P<0.01）,7.5μg/mL时,ROS水平降低45.99%,MDA下降58.77%,LDH下降71.61%,GSH提高206.60%(P<0.05),抗氧化酶相关基因...     

3种黄酮对脂肪肝细胞氧化应激的影响

目的：评价表没食子儿茶素没食子酸酯(EGCG)、表儿茶素、柚皮素3种食源性黄酮对降低脂肪肝细胞模型中氧化应激水平的作用。方法：采用油酸诱导的HepG2细胞建立脂肪肝模型,根据细胞存活率、乳酸脱氢酶(LDH)释放量和活性氧产生量反映细胞损伤程度及氧化应激状态,通过黄酮物质处理后的脂肪肝细胞模型活性氧减少量评价其缓解脂肪肝氧化应激状态的功效。结果：EGCG的抗氧化能力优于表儿茶素,两种物质的抗氧化能力随浓度增加而增强,呈量效关系。柚皮素的抗氧化作用最弱,100μmol/L柚皮素具有促氧化作用。     

玉米肽Tyr-Phe-Cys-Leu-Thr对酒精性HepG2细胞的保护作用

以从玉米蛋白粉中鉴定得到的玉米肽Tyr-Phe-Cys-Leu-Thr(YFCLT)为研究对象,通过体外抗氧化试验和细胞模型试验,从氧化应激与脂质代谢两个方面探讨其对HepG2细胞酒精性损伤的保护作用。体外抗氧化试验结果表明:玉米肽Tyr-Phe-Cys-Leu-Thr在较低浓度1μmol/L时仍具有一定的DPPH自由基清除能力、ABTS自由基清除率、铁螯合能力和氧自由基吸收能力(ORAC)。采用酒精为诱导剂诱导建立人肝癌细胞(HepG2)酒精性损伤模型,酒精最佳作用浓度为500 mmol/L,作用24 h。HepG2细胞酒精性损伤模型试验结果表明:玉米肽Tyr-Phe-Cys-Leu-Thr具有通过降低模型细胞ALT、AST的泄漏量,降低SOD、CAT、GSH酶活力,降低ROS和细胞TNF-α释放量而起到抗氧化应激损伤的HepG2细胞保护作用。玉米肽Tyr-Phe-Cys-Leu-Thr也可降低HepG2细胞内TG含量及减弱脂过氧化。综合各指标,玉米肽Tyr-Phe-Cys-Leu-Thr对HepG2细胞酒精性损伤具有保护作用。     

灵芝孢子和抗性淀粉对糖尿病大鼠糖脂代谢及氧化应激的协同干预

目的：探讨灵芝孢子和抗性淀粉对Ⅱ型糖尿病大鼠糖脂代谢及氧化应激的作用和机制。方法：采用链脲佐菌素诱导的方法建立Ⅱ型糖尿病模型,考察灵芝孢子和抗性淀粉对糖尿病大鼠的血糖、血脂及氧化应激指标的影响。结果：抗性淀粉和灵芝孢子均可改善糖尿病大鼠血糖水平,对抗糖尿病引起的氧化应激损伤。抗性淀粉降血糖、抗氧化作用较强,灵芝孢子粉调节大鼠脂代谢紊乱效果明显,抗性淀粉和灵芝孢子协同作用可进一步改善脂代谢水平,增强二者抗氧化能力。结论：抗性淀粉和灵芝孢子粉协同干预模式和传送方式可有效降低糖尿病大鼠的血糖水平,改善脂代谢紊乱,提高抗氧化应激的能力,可作为一种较好的减缓糖尿病症状的有效饮食干预方法。     

牦牛乳酪蛋白酶解物对H_2O_2诱导的氧化损伤HepG2细胞蛋白羰基含量及抗氧化酶活性的影响

为探究牦牛乳酪蛋白酶解物缓解氧化应激损伤的作用,利用过氧化氢(H_2O_2)建立氧化损伤细胞模型,以细胞蛋白质羰基含量及超氧化物歧化酶(superoxide dismutase,SOD)、谷胱甘肽过氧化物酶(glutathione peroxidase,GSH-Px)、过氧化氢酶(catalase,CAT)的活性为指标评价牦牛乳酪蛋白酶解物的活性。结果表明,利用酶解物处理H_2O_2损伤的HepG2细胞,能够缓解H_2O_2诱导的蛋白质羰基含量升高,并增加细胞内SOD、CAT、GSHPx的活性,从而提高机体抗氧化能力,缓解H_2O_2引发的氧化应激状态。研究证明,牦牛乳酪蛋白酶解物具有缓解氧化应激损伤的作用,为牦牛乳资源的进一步开发利用及乳源活性肽应用于抗氧化功能食品提供了依据。     

植物多酚通过Nrf2/ARE信号通路抗氧化作用研究进展

植物多酚是植物体内重要的次生代谢产物,是重要的天然抗氧化剂,能够清除自由基和淬灭活性氧。Nrf2（NF-E2-related factor 2）/抗氧化反应元件（antioxidant response element,ARE）信号通路是增强机体抗氧化功能最重要的保护性信号途径,在细胞抵御氧化应激机制中有着重要的地位,是抗氧化研究领域的热点。本文综述了Nrf2/ARE信号通路的组成及其调节机制,总结植物多酚通过该信号通路增强机体抗氧化应激能力,减少细胞凋亡、参与神经保护、延缓衰老和减少氧化损伤等的能力,以期为植物多酚应用于抗氧化保健食品和药品的开发提供一定依据。     

乳清蛋白源抗氧化肽的酶法制备及评价方法的研究进展

氧化应激可引起细胞损伤和多种慢性疾病,饮食中的抗氧化剂可以帮助人体清除自由基。人工合成的抗氧化剂虽然具有很强的活性,但在机体内存在潜在的风险,因此,人们把目光转向了天然的抗氧化剂。近年来乳清中的乳清蛋白因其衍生肽具有较强的抗氧化活性而备受关注。该文综述了乳清蛋白源抗氧化肽的酶法制备及抗氧化的作用机理,归纳并对比了其抗氧化活性评价方法,指出了目前乳清蛋白源抗氧化肽在动物机体内的活性评价及作用机理方面的研究仍存在不够深入的问题,以期为进一步综合利用乳清蛋白产品提供思路。     

红毛藻多糖对H2O2诱导的Caco-2细胞氧化损伤的保护作用

目的：研究红毛藻多糖（Bangia fusco-purpurea polysaccharide,BFP）对H2O2诱导的人结肠腺癌（Caco-2）细胞氧化应激损伤的保护作用。方法：构建过氧化氢（H2O2）诱导的Caco-2细胞氧化损伤模型,通过形态学观察和测定细胞裂解液中的抗氧化物水平及相关酶活力,评价BFP对Caco-2细胞氧化损伤的保护作用。结果：BFP可明显提高H2O2诱导氧化损伤的Caco-2细胞活力,降低细胞内活性氧生成水平,提高细胞内超氧化物歧化酶和过氧化氢酶活力以及还原型谷胱甘肽水平,减少丙二醛生成,并通过抑制Caspase-3和Caspase-9活性来改善氧化应激损伤引起的细胞凋亡。结论：BFP对H2O2诱导氧化应激损伤的Caco-2细胞具有保护作用,可通过增强细胞内源性抗氧化酶活力、提高非酶类抗氧化物水平和抑制细胞凋亡明显缓解H2O2诱导的Caco-2细胞氧化应激损伤。     

芦荟多糖对D-半乳糖致HepG2细胞氧化损伤的保护作用

目的:探讨芦荟多糖对HepG2细胞氧化损伤的保护作用,分析其体外抗氧化能力。方法:以HepG2细胞为研究对象,建立D-半乳糖诱导细胞氧化损伤模型,以不同浓度芦荟多糖进行预保护处理。采用细胞增殖与毒性检测试剂盒测定HepG2细胞存活率,生物化学法检测细胞超氧化物歧化酶、过氧化氢酶、谷胱甘肽过氧化物酶活力,酶联免疫吸附法测定细胞总抗氧化能力及丙二醛（malondialdehyde,MDA）含量,实时荧光定量PCR检测细胞Keap1、Nrf2、NQO1和HO-1基因表达水平。结果:与D-半乳糖模型组比较,25、50、100 μg/mL的芦荟多糖预保护处理能不同程度地提高HepG2细胞存活率;芦荟多糖能显著增强细胞中抗氧化酶的活性,降低细胞MDA的生成量（P<0.05）,且作用效果与芦荟多糖浓度成正比;细胞中Keap1基因表达显著降低,Nrf2、NQO1、HO-1 mRNA表达显著提高（P<0.05）。结论:芦荟多糖可以减轻HepG2细胞的氧化应激损伤,激活Nrf2表达并抑制其泛素化降解,提高下游NQO1、HO-1的转录水平,增强细胞抗氧化酶系活性并调控细胞氧化还原系统,以达到减轻细胞氧化损伤程度、提高细胞抗氧化应激损伤的效果。     

线粒体氧化应激与天然抗氧化剂研究进展

活性氧主要来源于线粒体呼吸,是一柄“双刃剑”,其在生理浓度时广泛参与细胞的信号转导和生命过程,过量时又能引起线粒体氧化应激,从而导致衰老及相关疾病的发生。如何保持细胞内的氧化与抗氧化平衡（氧化还原平衡）,既不过度氧化损伤,也不过度抗氧化而影响正常的信号转导,这对健康极为重要。因此,细胞氧化还原调控与衰老机制不再是简单的“衰老的自由基学说”,也不再是简单的抗氧化延缓衰老。抗氧化剂是身体健康所必需的,富含抗氧化剂的膳食有助于心血管疾病、神经退行性疾病、癌症等重大疾病发病率的降低。本文从线粒体氧化应激、抗氧化剂的必要性和来源、抗氧化防御系统、氧化还原平衡与抗氧化悖论、天然抗氧化剂等方面阐述氧化与抗氧化平衡对健康的重要性,为促进健康并延缓衰老提供新的思路。     

Dietary Intake of Natural Antioxidants: Vitamins and Polyphenols

Oxidative stress is a condition in which oxidant metabolites exert their toxic effect because of an increased production or an altered cellular mechanism of protection; oxidative stress is rapidly gaining recognition as a key phenomenon in chronic diseases. Antioxidants terminate these chain reactions by removing free radical intermediates, and inhibit other oxidation reactions by being oxidized themselves. Endogenous defence mechanisms are inadequate for the complete prevention of oxidative damage, and different sources of dietary antioxidants may be especially important. This article calls attention to the dietary antioxidants, such as vitamins A, C, and E and polyphenols. Compelling evidence has led to the conclusion that diet is a key environmental factor and a potential tool for the control of chronic diseases. More specifically, fruits and vegetables have been shown to exert a protective effect. The high content of minerals and natural antioxidant as vitamins A, C, and E and polyphenols in fruits and vegetables may be a main factor responsible for these effects.     

Invited review: Whey proteins as antioxidants and promoters of cellular antioxidant pathways

Oxidative stress contributes to cell injury and aggravates several chronic diseases. Dietary antioxidants help the body to fight against free radicals and, therefore, avoid or reduce oxidative stress. Recently, proteins from milk whey liquid have been described as antioxidants. This review summarizes the evidence that whey products exhibit radical scavenging activity and reducing power. It examines the processing and treatment attempts to increase the antioxidant bioactivity and identifies 1 enzyme, subtilisin, which consistently produces the most potent whey fractions. The review compares whey from different milk sources and puts whey proteins in the context of other known food antioxidants. However, for efficacy, the antioxidant activity of whey proteins must not only survive processing, but also upper gut transit and arrival in the bloodstream, if whey products are to promote antioxidant levels in target organs. Studies reveal that direct cell exposure to whey samples increases intracellular antioxidants such as glutathione. However, the physiological relevance of these in vitro assays is questionable, and evidence is conflicting from dietary intervention trials, with both rats and humans, that whey products can boost cellular antioxidant biomarkers.     

A new potent natural antioxidant mixture provides global protection against oxidative skin cell damage

Oxidative stress occurs when there is an over production of free radicals and cells are not able to neutralize them by their own antioxidant mechanisms. These excess of free radicals will attack cellular macromolecules leading to cell damage, function impairment or death. Because of that, antioxidant substances have been largely used in products to offer complementary protection. In this study a new mixture of three known antioxidants (cocoa, green tea and alpha‐tocopherol) was evaluated and its antioxidant protection was assessed focusing on its capacity to protect main cell macromolecules. Results have shown that it has a high antioxidant capacity by protecting lipids, DNA and proteins against oxidative damage. The antioxidant effect of the mixture on cells was also investigated and it was able to reduce oxidative stress generated by lipopolisacharide in human fibroblasts. Finally, as the mixture has proved to be highly antioxidant, its effect on cell senescence was evaluated, and it was demonstrated that fibroblasts in culture had delayed senescence when treated with these actives on a mixture. All results together provide important data about a new antioxidant mixture that uses a small amount of actives and is able to protect cell against oxidative damages in a global way.     

Chemoprotective action of l-(+)-selenomethionine on the modulation of genes involved in oxidative stress and in the UPR pathway

The installation of oxidative process arises from an imbalance between oxidants and antioxidants compounds, in favor of excessive generation of free radicals. This process can affect cellular components, like endoplasmic reticulum (ER). The ER is extremely sensitive to changes in homeostasis, where, on different stimuli, may result in adaptation to survival or induction of apoptosis (unfolded protein response, “UPR” pathway). The oxidative damage caused by endogenous or exogenous agents or a dysregulation of the UPR pathway can lead to adverse conditions, whose chronicity has important implications for the etiology of chronic diseases, including cancer. Therefore, it becomes important to search for chemoprotective agents aiming their role in preventive medicine. Between these substances, selenium’s antioxidant activity seems to be effective in treating diseases which have the oxidative stress as its development. We evaluated the modulating action of l-(+)-selenomethionine (SeMet) in HepG2 cells against cellular stress induced by H₂O₂ through MTT assay, comet assay, and gene expression by qRT-PCR of genes related to oxidative stress, UPR pathway, and apoptosis. In MTT assay, the lower concentrations of SeMet showed a cytoprotective action against the damage caused by H₂O₂. Likewise, it was verified in the comet assay that the concentration of 50 ng/mL reduced the genotoxic damage caused by H₂O₂. SeMet at 50 ng/mL regulated the genes tested in the qRT-PCR, showing an antiapoptotic and antioxidant effect. These results suggest that SeMet positively modulates the genes of oxidative stress and ER, leading to a chemoprotective and antioxidant effect, becoming an alternative in preventive medicine.     

抗氧化剂耦合非生物胁迫调控微藻油脂和类胡萝卜素合成的研究进展北大核心CSCD

微藻代谢物产率低的问题制约了微藻的产业化发展,近年来利用抗氧化剂耦合非生物胁迫成为有效解决微藻代谢物产率低的方法之一。为了对微藻在非生物胁迫条件下高效合成油脂和类胡萝卜素提供新的思路,综述了抗氧化剂耦合非生物胁迫调控微藻合成油脂和类胡萝卜素的研究进展,并进一步分析了抗氧化剂调控次级代谢产物合成和微藻细胞抗性的作用机制。抗氧化剂可通过调控微藻细胞内氧化还原平衡、信号转导和相关基因的转录水平,维持微藻生长,促进代谢产物的积累,并缓解氧化损伤。     

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.     

酒精诱导氧化应激小鼠模型建立及姜黄素抗氧化活性的初步研究

目的建立酒精诱导的氧化应激小鼠模型,对姜黄素的抗氧化活性进行初步评价,探讨补充生物活性因子的抗氧化功能评价方法。方法8周龄,昆明小鼠60只,动物房适应1周,按体重随机分为5组。实验周期内,每日按0.2ml/10g·BW给予各组实验小鼠连续灌服相应剂量受试物。实验结束时,处死全部小鼠,取血,测定肝脏相关生化指标。结果酒精模型组血浆和肝脏谷胱甘肽过氧化酶GPx的酶活性均显著低于正常对照组(P0.05);肝脏蛋白质羰基含量(PCO)显著高于正常对照组(P0.05)。结论长期摄入低浓度酒精,可以诱导建立氧化应激小鼠模型;实验中姜黄素的抗氧化活性得到初步证实;蛋白质羰基含量的测定显示,其可有效补充生物活性因子抗氧化功能评价方法。