Chemical characterization and chemo-protective activity of cranberry phenolic powders in a model cell culture. Response of the antioxidant defenses and regulation of signaling pathways

Oxidative stress and reactive oxygen species (ROS)-mediated cell damage are implicated in various chronic pathologies. Emerging studies show that polyphenols may act by increasing endogenous antioxidant defense potential. Cranberry has one of the highest polyphenol content among commonly consumed fruits. In this study, the hepato-protective activity of a cranberry juice (CJ) and cranberry extract (CE) powders against oxidative stress was screened using HepG2 cells, looking at ROS production, intracellular non-enzymatic and enzymatic antioxidant defenses by reduced glutathione concentration (GSH), glutathione peroxidase (GPx) and glutathione reductase (GR) activity and lipid peroxidation biomarker malondialdehyde (MDA). Involvement of major protein kinase signaling pathways was also evaluated. Both powders in basal conditions did not affect cell viability but decreased ROS production and increased GPx activity, conditions that may place the cells in favorable conditions against oxidative stress. Powder pre-treatment of HepG2 cells for 20 h significantly reduced cell damage induced by 400 μM tert-butylhydroperoxide (t-BOOH) for 2 h. Both powders (5–50 μg/ml) reduced t-BOOH-induced increase of MDA by 20% (CJ) and 25% (CE), and significantly reduced over-activated GPx and GR. CE, with a significantly higher amount of polyphenols than CJ, prevented a reduction in GSH and significantly reduced ROS production. CJ reversed the t-BOOH-induced increase in phospho-c-Jun N-terminal kinase. This study demonstrates that cranberry polyphenols may help protect liver cells against oxidative insult by modulating GSH concentration, ROS and MDA generation, antioxidant enzyme activity and cell signaling pathways.     

Alleviation effect of heat-treated and in vitro gastrointestinal digested soymilks on AAPH-induced oxidative stress in human erythrocytes: Digested soymilks alleviate oxidative stress

To investigate the potential protective effect of raw and heat-treated soymilks after gastrointestinal digestion against chemical oxidative stress induced by 2,2′-azobis(2-amidinopropane) dihydrochloride (AAPH) on human erythrocytes, soymilk was subjected to heat treatment and in vitro gastrointestinal digestion. The inhibition rate of hemolysis, generation of reactive oxygen species (ROS), concentration of malondialdehyde (MDA), reduced glutathione (GSH) and oxidized glutathione (GSSH) and the enzyme activity of total superoxide dismutase (SOD) and cellular glutathione peroxidase (GPx) were evaluated as the biomarkers of oxidative status. Hemolysis of erythrocytes induced by AAPH was significantly inhibited by pretreatment with the digested raw soymilk (DRS) and digested heat-treated soymilk (DHS). Moreover, heat treatment prior to gastrointestinal digestion improved the inhibition effect of soymilk on erythrocytes hemolysis. The soymilk treated at 95 °C showed the highest inhibition rate, followed by 121 °C and 143 °C, revealed that the increase of temperature caused the decrease of hemolysis inhibition rate of DHS. Preincubation with the digested soymilks reduced the accumulation of MDA in erythrocytes, indicating the inhibition effect of the digested soymilks on lipid peroxidation. Results revealed that DRS and DHS alleviated the hemolysis of erythrocytes and lipid peroxidation resulted from oxidative stress by suppressing the accumulation of ROS, reducing the increase of SOD activity and decrease of non-enzymatic antioxidant GSH and enzymatic antioxidant GPx activity. Compared with raw soymilk, heat treatment improved the protective effect of the digested soymilk on erythrocytes against oxidative stress via enhancing the free radicals scavenging activity instead of improving the inhibition effect on the generation of free radicals.     

基于HepG2细胞模型研究普洱茶茶色素的抗氧化作用

采用正常培养和油酸诱导培养的HepG2细胞为模型,通过测定普洱茶茶色素对HepG2细胞外谷胱甘肽(glutathione,GSH)含量,过氧化氢酶(catalase,CAT)活力和细胞内丙二醛(malondialdehyde,MDA)含量的影响,以研究普洱茶茶色素的抗氧化作用。结果显示,普洱茶茶色素对正常培养的HepG2细胞的抗氧化作用影响不显著,而对油酸诱导的HepG2细胞模型抗氧化作用有显著的提高。抗氧化作用提高的程度依赖于普洱茶茶色素的质量浓度。当400μg/m L普洱茶茶色素作用HepG2油酸诱导模型24 h,细胞外GSH含量由0.004 4 g/L增加到0.010 3g/L,CAT活力由0.136 U/m L提高至1.174 U/m L,细胞内MDA含量由15.146 nmol/mg减少到7.635 nmol/mg,从而使这些指标接近正常培养HepG2细胞模型水平。因此,普洱茶茶色素的抗氧化作用是通过提高清除活性氧的酶活力和促进合成还原性物质来干预细胞的氧化应激。     

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...     

山莴苣苦素改善FFA诱导的HepG2细胞脂肪变性及氧化应激的研究

目的:研究山莴苣苦素对游离脂肪酸(FFA)诱导的HepG2细胞脂肪变性的改善作用,并初步探讨其可能作用机制.方法:观察山莴苣苦素对HepG2细胞活力的影响.采用FFA诱导培养HepG2细胞,构建脂肪变性模型(NAFLD体外模型),并用山莴苣苦素干预72h后,检测各组细胞内脂滴数量、甘油三酯(TG)和总胆固醇(TC)含量...     

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。     

玉簪多糖对细胞氧化应激损伤的保护作用机制

本实验以紫萼玉簪（Hosta ventricosa）为原材料，采用响应面法优化其根系多糖（Hosta ventricosa root polysaccharide，HVRP）的提取工艺，探索HVRP对叔丁基过氧化氢（tert-butyl hydroperoxide，t-BHP）诱导的HepG2细胞氧化应激损伤的保护作用机制。结果表明：在提取温度84 ℃、提取时间3 h、料液比1∶31条件下，HVRP平均提取率达到23.9%；HVRP中还原性糖、蛋白质、糖醛酸的质量分数分别为11.17%、0.6%、12.31%，含有多糖类物质的特征吸收峰，不存在三螺旋构象。体外抗氧化和细胞实验结果表明，HVRP具有较强的抗氧化活性，能显著或极显著降低t-BHP诱导氧化损伤HepG2细胞内活性氧、丙二醛含量并提高过氧化氢酶、超氧化物歧化酶、还原型谷胱甘肽及谷胱甘肽过氧化物酶水平（P＜0.05、P＜0.01）。通过实时荧光定量聚合酶链式反应和蛋白质免疫印迹分析发现，HVRP可通过调控Kelch样环氧氯丙烷相关蛋白1/核因子E2相关因子2/抗氧化反应元件信号通路促进抗氧化酶表达，从而改善t-BHP诱导的HepG2细胞氧化损伤。本研究可为阐明HVRP抗氧化作用机制及其在功能性食品中的应用提供理论依据。     

Dihydrocaffeic acid,a major microbial metabolite of chlorogenic acids,shows similar protective effect than a yerba mate phenolic extract against oxidative stress in HepG2 cells

The hepatoprotective effect of a yerba mate phenolic extract (YMPE), rich in chlorogenic acids, and its main circulating metabolites dihydrocaffeic (DHCA) and dihydroferulic (DHFA) acids were assessed in human hepatoma HepG2 cells subjected to oxidative damage induced by tert-butylhydroperoxide (t-BOOH). Direct treatment of HepG2 cells with realistic concentrations of YMPE (1, 10 and 50 μg/mL), DHCA or DHFA (0.2, 1, 10 μM) for 20 h was not cytotoxic and significantly decreased ROS generation. Pre-treatment with YMPE and DHCA prevented the cytotoxicity and macromolecular damage induced by t-BOOH. Moreover, decreased levels of reduced glutathione (GSH), and increased ROS levels and antioxidant enzyme activity induced by t-BOOH were dose-dependently recovered. DHFA only showed a slight protection against cell cytotoxicity, lipid oxidation and GSH depletion. In conclusion, YMPE and one of its major microbial metabolites, DHCA, confer significant protection against oxidative damage, adding evidences to the beneficial health effects associated with mate intake.     

草苁蓉提取物对HepG2细胞氧化应激损伤的保护作用

目的：研究草苁蓉乙醇提取物（Boschniakia rossica ethanol extract,BREE）对H2O2诱导的HepG2细胞氧化应激损伤的保护作用。方法：用H2O2诱导HepG2细胞氧化应激损伤,采用噻唑蓝（methylthiazolyldiphenyltetrazoliumbromide,MTT）比色法检测BREE对HepG2细胞氧化损伤的保护作用;比色法测定培养液中乳酸脱氢酶（lactate dehydrogenase,LDH）、谷丙转氨酶（alanine aminotransferase,ALT）、谷草转氨酶（aspartateaminotransferase,AST）的释放率,以及细胞中超氧化物歧化酶（superoxide dismutase,SOD）、还原型谷胱甘肽（reduced glutathione,GSH）及丙二醛（malondialdelyde,MDA）水平;蛋白印迹法测定细胞外信号调节蛋白激酶（extracellular signal-regulated kinase,ERK）、c-Jun氨基末端激酶（c-Jun N-terminal kinase,JNK）、p38丝裂原活化蛋白激酶（p38 mitogen-activated protein kinase,p38 MAPK）总蛋白及其磷酸化形式的表达水平以及核转录因子-κB（nuclear factor-κB,NF-κB）的核内转移。结果：BREE单独处理时,在所测质量浓度范围内对HepG2细胞增殖无显著影响。与模型组相比,BREE能显著提高氧化损伤细胞的存活率;降低氧化损伤细胞培养液中LDH、ALT和AST的释放;降低细胞MDA水平,增高细胞SOD活性和GSH含量。氧化损伤发生的不同时期,ERK、JNK、p38 MAPK和NF-κB蛋白均有激活,而BREE在氧化损伤发生1 h时减少ERK激活和NF-κB核转移,氧化损伤发生12 h时减少JNK蛋白激活。结论：BREE对H2O2所致HepG2细胞氧化应激损伤具有保护作用,此作用可能与其抑制ERK、JNK的活化和NF-κB的核内转移有关。     

Hepatoprotective effects of lycopene against carbon tetrachloride-induced acute liver injury in rats

Lycopene, the major carotenoid in tomatoes, is a known antioxidant that may lower oxidative stress biomarkers by a mechanism that is not fully elucidated. The intoxication of rats with carbon tetrachloride (CCl₄) resulted in significant histological hepatic degradation accompanied by a marked increase in reactive oxygen species (ROS) and in the number of apoptotic cells. The induced oxidative stress in turn results in a significant elevation of lipid peroxidation and H₂O₂ generation, together with a decrease in the concentration of reduced glutathione (GSH) and a significant reduction in activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and glutathione S transferase (GST). CCl₄-intoxicated rats, pre-treated with lycopene, showed strongly reduced cell damage and ROS generation. The level of markers for hepatic integrity in lycopene pre-treated rats was close to the controls in the absence of CCl₄ treatment, indicating the protective effect of lycopene pre-treatment. In the same way, lycopene pre-treated rats significantly increased SOD, CAT, GPx, GST activities and GSH level. In addition, we measured an increased lipoxygenase (LOX) activity in CCl₄-intoxicated rats. This activity was reduced in lycopene pre-treated rats to values close to those observed in the controls, suggesting a potential pharmacological application of this dietary carotenoid.     

Chemo-protective activity and characterization of phenolic extracts from Corema album

There is currently substantial interest in the cyto-protective effects of natural compounds against oxidative stress and in studying of the defense mechanisms involved. Corema album fruit is an edible berry consumed along the Atlantic littoral of the Iberian Peninsula. The aim of this study was to characterize the phenolic composition and evaluate the chemo-protective effects against oxidative stress of three phenolic extracts from this fruit on liver cells.Characterization of phenolic compounds, achieved by liquid chromatography and diode-array, mass spectrometry and electrospray ionization-time of flight-mass spectrometry detection, showed a main fraction of hydroxycinnamic acids. Liver HepG2 cells were treated with 1–40 μg/mL of the extracts and exposed to oxidative stress chemically induced. Cell viability, reactive oxygen species (ROS), reduced glutathione (GSH), antioxidant enzymes and biomarkers of oxidative damage were evaluated.Treatment of HepG2 cells with the extracts partially prevented ROS increase, GSH depletion, antioxidant enzymes over-activity and oxidative damage to proteins and lipids induced by stress. The results support the traditional use of C. album as a medicinal plant and suggest that inclusion of its berries in the diet would contribute to the protection afforded by fruits, vegetables and plant-derived beverages against oxidative stress related diseases.     

Protective effect of Perilla frutescens cv. Chookyoupjaso mutant water extract against oxidative injury in vitro and in vivo

The aim of this study was to elucidate the protective ability of the Perilla frutescens cv. Chookyoupjaso mutant water extract (PFWE) against oxidative injury in vitro and in vivo. In in vitro experiments, our results showed that PFWE indicated the intracellular reactive oxygen species (ROS) scavenging activity as well as cytoprotective effect in SIN-1-treated HepG2 cells. The intracellular ROS scavenging activity of PFWE was 44% at 50 μg/mL, 50% at 100 μg/mL, and 56% at 200 μg/mL. Furthermore, in vivo results showed that treatment with PFWE attenuated the activity of serum alkaline phosphatase (ALP) and lipid peroxidation increased by carbon tetrachloride (CCl₄) and also markedly recovered the activity of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and glutathione reductase (GR) decreased by CCl₄ in BALB/c mice. GPx activity was elevated almost 3-fold compared to control group at 50 mg/kg of PFWE. The present study suggests that PFWE possesses significant protective effects against oxidative injury.     

荔枝果壳原花青素对中波紫外线诱导HaCaT细胞氧化损伤的保护作用

为评价荔枝果壳原花青素对中波紫外线（ultraviolet B,UVB）（波长280～320 nm）诱导人永生化角质形成细胞（HaCaT）氧化损伤的保护作用。构建UVB辐射HaCaT细胞氧化损伤模型,研究荔枝果壳低聚原花青素（litchi pericarp oligomolymeric procyanidins,LPOPC）及从中分离鉴定的6 种单体化合物对HaCaT细胞氧化损伤的保护作用。实验分为对照组、UVB照射组、实验组（阳性对照对氨基苯甲酸（para-aminobenzoic acid,PABA）、LPOPC及6 种单体化合物）,以CCK-8法测定各组细胞活力,采用试剂盒检测各组细胞内活性氧自由基（reactive oxygen species,ROS）相对含量,超氧化物歧化酶（superoxide dismutase,SOD）、过氧化氢酶（catalase,CAT）、谷胱甘肽过氧化物酶（glutathione peroxidase,GSH-Px）活力,还原型谷胱甘肽（glutathione,GSH）及丙二醛（malondialdehyde,MDA）含量。结果表明：LPOPC及6 种单体化合物的干预处理均可明显提高UVB诱导氧化损伤的HaCaT细胞活力,减少细胞内ROS和MDA的生成,增加SOD、CAT、GSH-Px的活力和GSH水平。6 种单体化合物中,原花青素A2的保护作用最明显,与阳性药物PABA的效果相当。结论：LPOPC及6 种单体化合物均可通过增强细胞内抗氧化能力、抑制脂质过氧化来明显改善受损细胞氧化应激损伤,对UVB诱导氧化损伤的HaCaT细胞具有良好的保护作用,提示原花青素A2是荔枝果壳原花青素中对氧化应激损伤防护作用最强的活性组分。     

Protective effect of carvacrol from <Emphasis Type="Italic">Thymus quinquecostatus</Emphasis> Celak against <Emphasis Type="Italic">tert</Emphasis>-butyl hydroperoxide-induced oxidative damage in Chang cells

Carvacrol is a monoterpenic phenol present in Thymus quinquecostatus Celak. The protective effects of carvacrol against tert-butyl hydroperoxide (t-BHP)-induced oxidative damage were investigated in human Chang cells. Cells treated with carvacrol extracts promoted Chang cell survival and protection was associated with stabilization of the mitochondrial membrane potential (MMP), prevention of oxidative stress-triggered reactive oxygen species (ROS), and lipid peroxidation (MDA production). In addition, Annexin V/PI, observed using Hoechst staining, indicated that carvacrol inhibited t-BHP-induced cell damage and stimulated the antioxidant capability of Chang cells due to elevation of glutathione (GSH) levels, which were reduced by t-BHP treatment. Carvacrol prevented oxidative stress-induced Chang cell damage via suppression of ROS and MDA levels, and increased GSH levels.     

采用HepG2细胞模型评价酒醅中短肽VPD和KGP的抗氧化活性

本研究针对前期实验从白酒酒醅中分离、提取和鉴定出的两种短肽Val-Pro-Asp (VPD)和Lys-Gly-Pro (KGP)的细胞水平抗氧化活性进行研究。以AAPH诱导氧化损伤的人体肝癌细胞(Human hepatoma cell,HepG2 cell)为模型,测定短肽对细胞内活性氧(ROS)含量、抗氧化酶的活性等指标。结果表明,VPD和KGP具有细胞内抗氧化活性,其作用机制体现在可以显著降低细胞内ROS含量,提高过氧化氢酶(CAT)、谷胱甘肽过氧化物酶(GSH-Px)和超氧化物歧化酶(SOD)三种酶的活力以及还原型谷胱甘肽(GSH)的含量,同时也能够通过降低细胞内脂质过氧化水平,如丙二醛(MDA)的含量来保护细胞免受氧化损伤,并且两种多肽的抗氧化能力随着浓度的上升基本呈现一定的增强趋势。综上所述,两种短肽在细胞水平具有一定的抗氧化能力,这为后续通过调整白酒蒸馏工艺条件,从而提高酒醅中功能性多肽进入白酒中的含量提供了可能。     

不同形态硒与VE联用对H_2O_2诱导人脐静脉血管内皮细胞氧化应激损伤的保护作用

目的:研究不同形态硒化合物(有机硒:L-硒甲基硒代半胱氨酸;无机硒:亚硒酸钠)单独使用及其与VE联合使用后对H_2O_2诱导人脐静脉血管内皮细胞(human umbilical vein endothelial cells,HUVECs)产生氧化应激损伤的保护作用。方法:采用体外细胞培养方法,将HUVECs随机分为7组:对照组、H_2O_2组、L-硒甲基硒代半胱氨酸(L-Se-methylselenocysteine,L-Se MSC)组、亚硒酸钠(sodium selenite,SS)组、VE组、L-Se MSC+VE联用组、SS+VE联用组。经不同样品干预处理后,采用四甲基偶氮唑蓝(methyl thiazolyl tetrazolium,MTT)法检测HUVECs存活率;检测各组细胞内脂质氧化终产物丙二醛(malondialdehyde,MDA)含量以及超氧化物歧化酶(superoxide dismutase,SOD)、谷胱甘肽过氧化物酶(glutathione peroxidase,GSH-Px)活性的变化。结果:各处理组HUVECs存活率之间没有显著差异;与H_2O_2组比较,0.1 mg/L亚硒酸钠、10 mg/L VE处理能使HUVECs内MDA生成量显著减少,SOD和GSH-Px活性显著升高,并且亚硒酸钠和VE联合使用在细胞水平上具有显著的协同作用,而L-Se MSC组与对照组无显著差异。结论:亚硒酸钠和VE均可保护由H_2O_2诱导引起的HUVECs氧化损伤,提高HUVECs抗氧化能力,并且亚硒酸钠和VE联用具有明显的协同抗氧化作用。     

Oxidative effects of Tartrazine (CAS No. 1934-21-0) and New Coccin (CAS No. 2611-82-7) azo dyes on CHO cells

Color is an indispensible characteristic of food because it makes foods easily recognizable and attractive in our modern society. Numerous food colors have been removed from the national and international lists of ??accepted food colors?? due to their mutagenic and carcinogenic activities based on a number of toxicity studies that have been conducted since food colors were first identified as carcinogenic by researchers. This study investigated the changes in oxidative stress parameters such as glutathione (GSH), malondialdehyde (MDA), glutathione peroxidase (GPx) activity, and catalase (CAT) activity that occurred when Chinese hamster ovary (CHO) cells were exposed to Tartrazine (CAS No. 1934-21-0) and New Coccin (CAS No. 2611-82-7), commonly-used azo dyes in the food industry. It was found that intracellular GSH significantly decreased, MDA levels increased, and GPx and CAT levels remained the same, (as compared to the control), when CHO cells were exposed to these food colors. Based on our results, Tartrazine and New Coccin food colors can be regarded as toxic. Considering the possible oxidative damage induced by these food colors, due to the depletion of GSH (a cell??s major antioxidant), and a significant increase in MDA levels, we strongly believe that the use of these potentially toxic colors in food needs to be reconsidered.     

Alterations in antioxidant enzyme activities and oxidative damage in alcoholic rat tissues: Protective role of Thespesia populnea

Recent advances in our understanding of the pathogenesis of alcohol-induced hepato-renal injury and the development of new approaches to its treatment have been reported in various works. This study involves alcohol-induced oxidative stress linked to the metabolism of ethanol involving both mitochondrial and peroxisomal fractions of liver and kidney. Alcohol treatment resulted in the depletion of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR), Glutathione-S-Transferase (GST) activities, and reduced glutathione (GSH) content, higher level of malondialdehyde (MDA) and lower levels of protein carbonyls (PC) causing malfunction of hepatic and renal tissues, when compared to control rats. Thespesia populnea (TP) leaf extracts, administered to chronic alcohol ingested rats, were envisaged to possess significant antioxidant defence properties and help in the recovery of tissues from alcohol-induced oxidative damage. The results showed that degenerative changes in hepatic and renal cells of alcoholic groups were minimized by the administration of TP leaf extracts as also revealed by histopathological examination. The current findings indicate that treatment with TP extracts reduces alcohol-induced oxidative stress, thereby protecting the hepatic and renal tissue from alcohol-induced damage.     

Intracellular ROS scavenging and antioxidant enzyme regulating capacities of corn gluten meal-derived antioxidant peptides in HepG2 cells

The objective of this study was to investigate the intracellular reactive oxygen species (ROS) scavenging activities and antioxidant enzyme regulating capacities of corn gluten peptide fractions (CPFs) in HepG2 cells. A cellular antioxidant activity (CAA) assay was used to assess their antioxidant activities and revealed that both CPF1 (molecular weight < 1 kDa) and CPF2 (molecular weight between 1 and 3 kDa) exhibited high cellular antioxidant activities with EC₅₀ values of 2.85 ± 0.19 mg/mL and 5.05 ± 0.32 mg/mL, respectively. Both CPFs also exhibited cytoprotective effects and intracellular ROS scavenging activities in HepG2 cells subjected to oxidative stress by oxidation with H₂O₂. In addition, at concentrations of 2.50 mg/mL, the CPFs increased the activity levels of superoxide dismutase (SOD), catalase (CAT), and glutathione reductase (GR), as well as the total glutathione (GSH) levels in oxidized HepG2 cells (from 86.54% to 114.14% (CPF1) or 109.72% (CPF2) for SOD activity; from 71.91% to 107.64% (CPF1) or 106.50% (CPF2) for CAT activity; from 70.52% to 103.01% (CPF1) or 104.10% (CPF2) for GR activity; and from 81.39% to 114.00% (CPF1) or 108.82% (CPF2) for total GSH levels). These results suggested that both CPF1 and CPF2 exhibited positive effects on the activities of the intracellular antioxidant enzymes SOD, CAT and GR, as well as on the total GSH levels in HepG2 cells under conditions of oxidative stress. Furthermore, size exclusion gel chromatography and MALDI-TOF/TOF mass spectrometry revealed that the molecular weights of the antioxidant peptides in CPF1 were between 500 Da to 900 Da, and a novel antioxidant peptide consisting of GLLLPH (Gly-Leu-Leu-Leu-Pro-His) was identified in CPF1.     

韩国产芝麻酱油对AAPH诱发LLC-PK1细胞氧化应激的保护作用

以芝麻酿造酱油乙醇提取物(ethanol extract sesame sauce,SSE)为研究对象,探讨其对1 mmol/L 2,2’-偶氮二异丁基脒二盐酸盐(2,2’-azobis(2-methylpropionamidine)dihydrochloride,AAPH)引发的LLC-PK1猪肾近曲小管上皮细胞氧化应激损伤的保护作用。方法:LLC-PK1细胞与不同质量浓度(10~100μg/m L)的SSE预先共同培养24 h后,用含AAPH的DMEM培养液继续培养4 h建立细胞损伤模型。细胞存活率用四甲基偶氮唑蓝法检测,细胞内丙二醛(malondialdehyde,MDA)含量和总活性氧簇(reactive oxygen species,ROS)水平分别以硫代巴比妥酸比色法和2’,7’-二氢二氯荧光黄双乙酸钠探针法测定。细胞内过氧化氢酶(catalase,CAT)、超氧化物歧化酶(superoxide dismutase,SOD)、谷胱甘肽过氧化酶(glutathione peroxidase,GSH-Px)、谷胱甘肽巯基转移酶(glutathione S-transferase,GST)、γ-谷氨酰半胱氨酸合成酶(γ-glutamylcysteine synthetase,γ-GCS)活力和谷胱甘肽(glutathione,GSH)含量按试剂盒说明书以比色法测定。结果表明,SSE预处理可以提高受损细胞存活率,降低细胞内总ROS水平和MDA含量。同时,SSE还能提高受损细胞内抗氧化酶(CAT、SOD、GSH-Px)及γ-GCS活力并提高细胞内GSH含量。实时荧光定量聚合酶链式反应分析也提示SSE能上调细胞内抗氧化物酶(CAT、SOD和GSH-Px)的m RNA表达量。此外,SSE可以通过提高细胞内源性抗氧化系统能力来降低细胞内MDA和ROS水平,并由此缓解AAPH对LLC-PK1细胞所造成的氧化应激损伤。