不同多糖配伍对H2O2诱导的皮肤细胞老化的抑制作用

本研究为明确混合多糖配伍使用抑制皮肤细胞衰老的作用是否优于单一多糖,通过利用不同浓度的H_2O_2诱导人皮肤成纤维细胞(HSF)、人角质形成细胞(Ha Ca T)出现损伤老化,在此基础上,采用MTT法和生化试剂盒检测,分别检测细胞的存活率及超氧化物歧化酶(SOD)、丙二醛(MDA)、羟脯氨酸(HYP)的含量。本实验所建立的Ha Ca T及HSF细胞过氧化模型的存活率分别约为72.00%和65.00%,研究发现四种单一多糖组对两种细胞老化模型的存活率与模型组相比差异没有统计学意义(p0.05);其中SOD、MDA、HYP的含量与模型组相比,除个别指标外,差异没有统计学意义(p0.05)。在Ha Ca T细胞老化模型中,混合多糖组的存活率在74.93%～80.43%之间,SOD含量在6.99 U/mg～7.56 U/mg之间,MDA含量在7.44μmol/g～8.41μmol/g之间,HYP含量表达在2.30μmol/g～2.43μmol/g之间;在HSF细胞老化模型中,混合多糖组的存活率在76.23%～78.14%之间,SOD含量在6.30 U/mg～8.90U/mg之间,MDA含量在7.03μmol/g～8.93μmol/g之间,HYP含量在2.19μmol/g～2.53μmol/g之间;以上指标与模型组相比差异均有统计学意义(p0.01或p0.05)。因此,混合多糖组的整体改善效果更为显著,它能够提高衰老表皮细胞生存率,提高模型细胞SOD、HYP含量,使MDA含量降低。研究提示我们在对抗H_2O_2诱导的HSF、Ha Ca T细胞氧化衰老实验中,在相同干预浓度下,不同多糖配伍后的混合多糖比组分单一多糖单独使用效果显著。     

软枣猕猴桃原花青素对H2O2诱导细胞损伤的预保护作用

研究软枣猕猴桃中原花青素类化合物对过氧化氢损伤人永生化表皮细胞(Ha Cat)的保护作用。以浏阳市大围山软枣猕猴桃为试材,以体外培养的Ha Cat细胞为实验对象。试验分为3组,分别为对照组、过氧化氢损伤组、处理组(软枣猕猴桃原花青素5～1000μg/mL预处理),以细胞内细胞存活率(凋亡率)、SOD(超氧化物歧化酶)、GSH-PX(谷胱甘肽过氧化物酶)、ROS(活性氧簇)、Nrf2基因及其蛋白表达水平为综合评价指标,评价其抗氧化性强弱。实验结果表明:当加入原花青素类化合物对细胞进行预保护后,5～500μg/L浓度的原花青素对损伤细胞的存活率为77%左右,较模型组提高了2.88倍。处理组细胞内SOD(10.46 U/mg prot)、GSH-PX水平(33.83 U/mg prot)较模型组升高了108.28%、137.48%,且存在明显差异(p0.05);而ROS水平显著下降,与模型组(96.21)相比细胞内平均荧光强度下降了48.60%。此时Nrf2基因及其蛋白表达量分别为1.40、35.11较模型组分别提高了63.93%、80.70%。这说明软枣猕猴桃中原花青素类化合物对H_2O_2造成Ha Cat细胞的氧化损伤具有一定的预保护作用,可进一步将其开发成相应的天然有效抗氧化剂产品应用于市场中。     

富硒油茶籽油对H2O2诱导HaCaT细胞氧化损伤的保护作用研究

探究油茶籽油对过氧化氢诱导人永生化表皮细胞(HaCaT)氧化损伤的保护作用。以油茶果经物理压榨所得油茶籽油为材料,以体外培养的HaCaT细胞为试验对象,试验分为空白对照组、过氧化氢(H_2O_2)模型损伤组、阳性对照组(VC)、处理组(油茶籽油5～500μg/m L预处理),以细胞内细胞存活率(凋亡率)、SOD、GSH-PX、ROS及其Nrf2基因表达水平为综合评价指标,评价油茶籽油的抗氧化性。结果表明:当加入油茶籽油对细胞进行预保护后,质量浓度50～200μg/m L的油茶籽油对损伤细胞的存活率在70%～82%之间,较H_2O_2模型损伤组的高。50μg/m L油茶籽油处理组细胞凋亡率为4. 49%,较H_2O_2模型损伤组降低了44. 77%;细胞内SOD水平(22. 09 U/mg)、GSH-PX水平(64. 50 U/mg)较H_2O_2模型损伤组升高了46. 68%、63. 66%,且存在明显差异(P 0. 05);而ROS水平显著下降,与H_2O_2模型损伤组(88. 27)相比细胞内平均荧光强度下降了37. 66%;此时Nrf2基因相对表达量为1. 13,较模型组提高了101. 78%;各指标均较优于阳性对照50μg/m L VC处理组的效果。说明油茶籽油对H_2O_2造成的氧化损伤具有一定的预保护作用,且好于相同质量浓度的VC处理效果,可进一步将其开发成相应的天然有效抗氧化剂产品。     

草苁蓉多糖对HepG2细胞氧化应激的抑制作用

研究草苁蓉多糖(BRPS)对过氧化氢(H_2O_2)所致HepG2细胞氧化应激的抑制作用。以HepG2细胞为研究对象,通过H_2O_2诱导细胞氧化应激损伤模型,采用四甲基偶氮唑盐比色(MTT)法检测细胞存活率;比色法检测培养液中乳酸脱氢酶(LDH)、谷草转氨酶(AST)、谷丙转氨酶(ALT)活性以及细胞中超氧化物歧化酶(SOD)、还原型谷胱甘肽(GSH)及丙二醛(MDA)水平;蛋白印迹法测定细胞外信号调节蛋白激酶(ERK)、c-Jun氨基末端激酶(JNK)、p38丝裂原活化蛋白激酶(p38)活化水平。结果表明,BRPS在质量浓度12.5 mg/L~50 mg/L范围内对HepG2细胞存活率无显著影响,对细胞安全。而H_2O_2诱导使HepG2细胞存活率和抗氧化能力下降,细胞内ERK和JNK磷酸化水平升高。与H_2O_2模型组相比,BRPS预处理可提高细胞存活率;降低培养液中LDH、AST和ALT活性;降低细胞内MDA含量,升高细胞中SOD活性和GSH含量,降低细胞内ERK和JNK磷酸化水平。提示,BRPS对H_2O_2所致HepG2细胞氧化应激具有抑制作用,减轻其细胞损伤。     

诸葛菜碱Ⅰ对H_2O_2所致HepG2细胞氧化损伤的保护作用

本文采用柱色谱技术对诸葛菜种子的提取物进行分离纯化,采用波谱技术结合化学方法进行结构鉴定,首次获得新化合物,命名为诸葛菜碱Ⅰ,并通过建立H_2O_2诱导的细胞损伤模型,对诸葛菜碱Ⅰ保护H_2O_2所致Hep G2细胞氧化损伤的作用及其机制进行了研究。于H_2O_2刺激前,加入不同浓度的诸葛菜碱Ⅰ预处理Hep G2细胞12 h,然后以400μmol/L H_2O_2损伤细胞2 h建立模型。MTT法检测细胞存活率,微板法检测细胞培养液中LDH活性和细胞MDA含量及SOD、GSH-PX的活性,Western Blot检测细胞内Nrf 2、HO-1蛋白表达,以评价诸葛菜碱Ⅰ对H_2O_2所致Hep G2细胞氧化损伤的保护作用。结果表明,与模型组相比,诸葛菜碱I给药组(53.5、107、214μmol/L)预处理12 h后,增加了细胞存活率(p0.01),显著降低LDH向细胞外液的释放(p0.01),显著降低细胞内MDA含量(p0.05,p0.01),显著提高细胞内SOD、GSH-PX的活性(p0.05,p0.01),增高了Nrf2蛋白水平。因此,诸葛菜碱Ⅰ对H_2O_2所致Hep G2细胞氧化损伤具有保护作用。     

蔓越莓抑制UVB诱导HaCaT细胞氧化损伤和凋亡的研究

研究蔓越莓对中波紫外线(UVB)诱导的人表皮角质形成细胞(Ha Ca T)光损伤的保护作用。用3个不同剂量的蔓越莓果汁预处理Ha Ca T细胞6 h,采用60 m J/cm~2强度UVB照射细胞;然后用MTT法检测细胞的生存率,吸取细胞上清液采用比色法检测丙二醛(MDA)、羟脯氨酸(Hyp)的含量和超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)、乳酸脱氢酶(LDH)的活性变化,用荧光法检测细胞内活性氧自由基(ROS)含量,用倒置显微镜和流式细胞仪观察检测细胞凋亡状况。UVB辐射对Ha Ca T细胞造成比较严重的损伤;相比于空白对照组,UVB辐射模型组Ha Ca T细胞活性下降了29.54%,SOD和GSH-Px活性极显著降低(P0.01);相比于模型组,蔓越莓各剂量组可显著提高UVB照射后Ha Ca T细胞的活力(P0.05或P0.01),提高SOD和GSH-Px活性(P0.01),减少MDA和ROS含量(P0.05或P0.01),并且降低LDH活性和增加Hyp含量(P0.01),呈剂量依赖关系,从而降低UVB所导致的细胞损伤及凋亡率升高。蔓越莓可以明显减少UVB诱导Ha Ca T细胞的氧化损伤和凋亡,具有显著的光保护功效,其作用机制与增强细胞抗氧化能力、加速清除氧自由基以及促进胶原蛋白合成有关。     

槟榔花中酚类物质对HSF细胞氧化损伤的保护作用

为了探讨槟榔花中3种主要酚类物质(表儿茶素、没食子酸、香豆酸)对人皮肤成纤维细胞(HSF)氧化损伤的保护作用,以H_2O_2(150μmol/L)处理HSF细胞24 h,建立氧化损伤模型,MTT法测定细胞存活率分光光度法检测细胞内总抗氧化能力和线粒体膜肿胀度,DCFH-DA染色法测定细胞内活性氧的含量。结果表明表儿茶素和没食子酸均能改善H_2O_2引起的HSF细胞的氧化损伤而香豆酸却没有保护作用。与H_2O_2模型组相比表儿茶素和没食子酸均能提高氧化损伤细胞的存活率,并将细胞内总抗氧化能力提高了4.73%~31.66%,细胞内活性氧和线粒体膜肿胀度也明显降低。表明槟榔花中2种主要的酚类物质表儿茶素和没食子酸对HSF细胞氧化损伤具有保护作用。     

沙棘粕提取物对H2O2诱导的B16F10细胞氧化损伤的保护及修复

研究了沙棘粕提取物(SBSE)对B16F10细胞氧化应激损伤的保护及修复作用。首先建立了过氧化氢(H_2O_2)诱导的B16F10细胞氧化损伤模型,完成了流式细胞术对损伤模型的评价;其次,研究了SBSE预处理对细胞防御H_2O_2诱导的氧化损伤细胞活力的影响,以及对损伤模型的修复作用;再次,比较了各SBSE处理组与模型组细胞谷胱甘肽过氧化物酶(GSH-Px)、超氧化物歧化酶(SOD)和过氧化氢酶(CAT)活性以及丙二醛(MDA)水平。结果:H_2O_2的诱导条件为300μg/mL处理4 h,流式细胞术检测发现,H_2O_2处理4 h后活细胞百分比由(91.61±1.14)%降至(49.77±2.74)%(P0.01),早期凋亡细胞由(1.97±0.34)%升至(17.91±3.55)%(P0.01),晚期凋亡率升至(21.24±2.61)%,并且H_2O_2处理6 h的晚期凋亡细胞显著上升,晚期凋亡率在60%以上。利用H_2O_2刺激SBSE预处理后的B16F10细胞,结果发现0.10 mg/mL SBSE处理后的细胞活力显著高于模型组(P0.05),抗氧化酶活力显著提升,细胞内MDA的积累显著降低;不同浓度SBSE处理损伤模型,0.10mg/mL SBSE具有一定的修复作用(P0.05),其GSH-Px、CAT和SOD活力显著高于模型组(P0.05,P0.01,P0.01),MDA水平显著降低(P0.05)。由此可见,SBSE通过提高细胞GSH-Px、CAT和SOD的活性,降低过氧化产物MDA的含量来保护和修复H_2O_2诱导的B16F10细胞氧化损伤。     

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。     

牡蛎寡肽对H2O2氧化损伤L02人肝细胞的保护作用

为了研究牡蛎寡肽对自由基清除作用及对人肝细胞L02细胞氧化损伤的保护作用,测定了牡蛎寡肽对羟自由基(·OH)的清除率,并建立过氧化氢(hydrogen peroxide,H_2O_2)氧化损伤人肝细胞L02的模型,研究牡蛎寡肽对氧化损伤L02细胞的存活率、活性氧(Reactive Oxygen Species,ROS)、抗氧化酶系(superoxide dismutase/SOD,glutathione/GSH)含量的影响。结果表明,牡蛎寡肽对羟自由基的IC_(50)为0.38 mg/m L。2 mg/m L牡蛎寡肽对于L02细胞的增殖率仍为123.98%。模型组SOD和GSH水平分别降低了40%、64.87%,而ROS增加了1倍。当添加不同剂量牡蛎寡肽后,中剂量组细胞中SOD含量几乎恢复到正常组水平,GSH活性也提高了118.89%,ROS水平降到模型组的62.43%,说明牡蛎寡肽对L02细胞无毒,能降低氧化损伤的L02细胞内的ROS水平,显著提高SOD和GSH含量,对细胞起到保护作用。因此,牡蛎寡肽对H2O2致氧化损伤的人肝L02细胞具有保护作用,可能是通过清除自由基,保护细胞内抗氧化酶系活性,抑制ROS的过多积累来实现。     

马铃薯蛋白组分的分离提取和功能性质研究

采用透析与等电点沉淀相结合的工艺方法提取分离马铃薯块茎蛋白组分;并对其理化性质和功能性质进行检测。结果显示：此提取工艺流程合理易行,马铃薯块茎酸性蛋白组分和碱性蛋白组分的得率分别为0 .535%、0.741%;纯度分别为92.5%、89.2%;酸性蛋白组分沉降系数5S,分子质量82kD;碱性性蛋白组分沉降系数8S,分子质量140kD。SDS-PAGE 电泳图谱表明5S 蛋白组分有1 条亚基带;8S 蛋白组分有4 条亚基带。5S 蛋白组分的表面疏水性、吸油能力、乳化性显著高于8S 蛋白组分;而8S 蛋白组分的总巯基含量以及起泡性高于5S 蛋白组分。马铃薯蛋白组分可以作为功能食品的蛋白添加原料。     

Butteroil Emulsification with Milk-Derived Membrane and Protein Fractions

Butteroil was emulsified by homogenization or ultrasound dispersal into aqueous phases containing milk lipid globule membrane, or combinations of membrane with lipid globule-derived and milk serum proteins. Stable emulsions containing about 50 mg protein/g butteroil were produced with all combinations. Protein composition of emulsions closely reflected protein composition of starting materials. Emulsions of equal stability, and with churn times equivalent to that of cream, were obtained with unprocessed butteroil and with a cholesterol-reduced butteroil produced by steam-stripping. Electron microscopic examination of fixed material showed that emulsions produced with all formulations predominantly were of the water-in-oil type, and not the oil-in-water type typical of milk lipid globules.     

Flavor Protein Interactions: Characteristics of 2-Nonanone Binding to Isolated Soy Protein Fractions

THE ABSORPTION COEFFICIENTS at 280 nm of 1% solutions of pure soy protein, β-conglycinin, glycinin, the acidic and basic sub-units of glycinin were 6.04, 4.4, 8.04, 7.18, and 8.8, respectively. Using equilibrium dialysis the binding affinities of these proteins for the model flavor compound 2-nonanone were determined. On an equivalent weight basis soy protein, β-conglycinin and glycinin had approximately 5,2 and 3 primary binding sites per 100,000 daltons and affinity constants (K) of 570, 3050 and 540 m^-1, respectively, i.e., β-conglycinin showed a fivefold greater affinity for nonanone than the other soy protein. The acidic and basic subunits showed binding behavior similar to that of glycinin.     

Air Classification and Extrusion of Navy Bean Fractions

Pilot plant air classification or raw beans (Phaseolus vulgaris) produced high-protein fractions (HPF) containing 51.4% protein and high-starch fractions (HSF) having about 50% starch. Particle size distribution analyses and scanning electron micrographs confinned the fractionation of starchy and proteinaceous materials. Extruded corn/HSF blends had lower water absorption and water solubility indices, higher protein content, and a better balanced amino acid pattern than pure corn extrudates. Extrusion-texturized vegetable proteins obtained by substituting HPF for defatted soy flour at levels of 10, 20 and 30% had similar functional properties as the 100% texturized soy. Air classification followed by extrusion-cooking is a feasible alternative for dry-processing of beans into products for human consumption.     

Amaranth Flour Blends and Fractions for Baking Applications

Selected Amaranthus eruentus ecotypes from different places of origin were used to prepare baking products. Amylograph, alveograph and farinograph data of mixtures of white wheat flour with whole amaranth grain flour from raw, toasted and popped amaranth seeds, as well as with higher protein fractions obtained by air classification, presented clear differences with respect to wheat flour. Six selected amaranth lines displayed different behaviors according to their origin and the seeds, previous treatment. Results indicate the opportunity of employing wheat-amaranth mixtures in programs developed to improve the diet of the population's marginal sectors. Enriched cookies and "bolillos" (French bread) with NPR values of 3.63 and 4.35, respectively, slightly higher than casein (3.0 and 4.0). are especially recommended for this purpose.     

Functional Properties of Extrudates from High Starch Fractions of Navy and Pinto Beans and Corn Meal Blended with Legume High Protein Fractions

High protein fractions (HPF) of navy and pinto beans were mixed with high starch fraction (HSF) or corn meal and extrusion-cooked. HSF of pintos blended with hull fractions was extruded at 132°C. Expansion index (EI), density, color, water absorption (WAI), water (WSI) and nitrogen solubility (NSI), oil absorption (OAC) and emulsification (OEC) were evaluated. Extruded blends had lower EI and OAC, higher protein density and OEC than extruded corn or HSF. WAI and WSI were variable. EI decreased with increased protein. Scanning electronic microscopy showed protein level had pronounced influence on microstructure, size of air cells and smoothness of cell walls. Hull fraction added to HSF, caused decreases in EI, WAI, WSI while NSI, OAC and OEC were unaffected.     

驴乳中蛋白质组分的分离纯化与鉴定

目的：分离纯化并鉴定驴乳乳清中蛋白质组分,为进一步研究驴乳用于辅助治疗疾病,以及为作为人乳替代品提供参考。方法：采用DEAE-52 离子交换层析和Sephadex G-100 凝胶层析分离纯化驴乳乳清中蛋白质组分,并通过十二烷基硫酸钠--聚丙烯酰胺凝胶电泳法和高效凝胶渗透色谱法对所纯化蛋白质进行鉴定。结果：与牛乳乳清中蛋白组分相对比,发现驴乳乳清中存在3 种未知蛋白质,分子质量分别为32、70.1、72.2kD。结论：驴乳中除了含有与牛乳相似的营养成分外,还具有其他生物活性成分,它们可能是一些保护性蛋白,在机体的抗病机制方面起着重要作用。     

Proteolytic and Milk Clotting Fractions in Milk Clotting Preparations

Five different milk clotting preparations were fractionated on Sephadex G-100 and then tested for milk clotting activity and for proteolysis of denatured hemoglobin. Two preparations were also tested for proteolytic activity on casein. Proteolytic activities on hemoglobin were correlated with clotting ability of bovine rennet, calf rennet, and rennin-pepsin mixture at pH 1.6 and with Mucor miehei protease at pH 5.2. Modified Mucor miehei protease activities on hemoglobin correlated equally well at pH 1.6 and 5.2. Gel filtration through Sephadex G-100 and elimination of nonclotting fractions reduced the proteolytic activities on hemoglobin at pH 5.2 of calf rennet, bovine rennet, Mucor miehei protease, modified Mucor miehei protease, and rennin-pepsin mixture by 68.6, 88.5, 3.7, 53.7, and 91.2%, respectively. At pH 1.6, proteolysis was reduced by 54.2, 41.2, 51.8, 59.5, and 60.8%. Proteolytic activities of bovine rennet and renninpepsin mixture on casein were reduced by 59.8 and 72%, respectively.     

不同级分蔗渣的制浆性能

选用不同目数的筛网对蔗渣进行分级处理,研究了不同级分蔗渣的纤维形态及由其制得的化学浆和化机浆的性能。结果表明,随着筛网目数的增大,各级分蔗渣原料的平均纤维长度逐渐减小,纤维粗度先减小后增大;蔗渣各级分制得浆的性能存在一定差异,通过40目筛网的级分与其他各级分差别较大。对化学浆而言,保留在40目筛网以上的各个级分的卡伯值和得率相差不是太大,而40目筛网以下级分的化学浆性能很差,应尽量予以除去;对化机浆而言,通过40目筛网的级分制得浆的松厚度较其他级分大,尘埃度极高,对抗张强度和耐破度影响较大,对环压强度和挺度影响相对较小。若对纸浆白度的要求不高,可适当保留40目筛网以下的级分,以提高松厚度。无论是化学浆还是化机浆,40目筛网以上的各个级分之间的机械强度差异均不是太大。     

Oxidative Stability of Cholesterol-Free Egg Lipid Fractions

Lipids were extracted from fresh egg yolk using hexane:isopropanol (3:2.v/v) and separated on a silicic acid column into triacylglycerol (TG), phospholipid (PL), cholesteryl ester and cholesterol fractions using hexane, ethyl acetate and methanol. TG and PL fractions were cholesterol-free. Oxidative stability at 35° C of crude lipids, TG, PL and combined TG + PL was evaluated over 12 days by measuring conjugated dienes, conjugated trienes and thiobarbituric acid reactive substances. PL and TG exhibited significantly higher oxidation than the crude lipids (alpha = 0.01). Combined TG + PL was not significantly different than the crude lipids (alpha = 0.01), showing much higher stability than individual TG or PL fractions.