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1.
气相色谱分析测定奶油中c9,t11—共轭亚油酸的含量 总被引:2,自引:0,他引:2
共轭亚油酸 (conjugatedlinoleicacid ,CLA) (以下简称CLA)是一类共轭双键位置在 9和 1 1或 1 0和1 2的亚油酸 (linoleicacid,LA)同分异构体的混合物 ,每个双键可以成顺式或反式构型[1] ,因而CLA最基本的空间构象是形成 8种同分异构体[2 ] 。国外的大量研究表明 ,CLA具有很多重要的生物活性作用[3~ 10 ] ,如CLA具有抑癌作用、降低胆固醇和抗动脉粥样硬化作用、抗氧化作用 ,能有效地防止免疫刺激的分解代谢作用等 ,而c9,t1 1 CLA被认为是生物活性作用最强的共轭亚油酸异构体。目… 相似文献
2.
目的:用气相色谱内标法检测部分市售牛奶中c9,t11-共轭亚油酸含量(CLA),分析季节因素对牛奶中e9,t11-共轭亚油酸含量的影响。方法:采用气相色谱内标法,内标物为C17:00甲酯,程序升温,将样品提取、甲酯化后,测定并比较夏季和非夏季牛奶样品中c9,t11-共轭亚油酸的含量。结果:实验方法的回收率为83.67%,RSD=3.45%;精密度为RSD=2.09%。夏季和非夏季牛奶样品中c9,t11-共轭亚油酸含量均值范围分别为0~14.9me,/g脂肪和0~7.3mg/g脂肪。夏季牛奶样品中c9,t11-共轭亚油酸含量显著高于非夏季牛奶样品(P〈0.05)。结论:所建立的实验条件准确可靠,季节变化对牛奶样品中c9,t11-共轭亚油酸含量有显著影响。本研究对在国内开展共轭亚油酸强化乳制品的研究具有指导意义。 相似文献
3.
目的:研究75%c9,t11-共轭亚油酸(c9,t11-CLA)在不同条件下的氧化稳定性,并在同等条件下与亚油酸(LA)进行比较,探讨影响75%c9,t11-CLA氧化稳定性的因素。方法:测定75%c9,t11-CLA和LA在暴露于空气、充氮保护、加入0.02%没食子酸丙酯、色拉油中及0.02%Ca^2+存在条件下的过氧化值,同时进行气相色谱分析,观察5个不同时间75%c9,t11-CLA和IA含量的变化。结果:当75%c9,t11-CLA和LA在暴露于空气、充氮保护、加入0.02%没食子酸丙酯、色拉油中及0.02%Ca^2+存在的条件下,75%c9,t11-CLA在不同处理条件下的氧化稳定性顺序为:0.02%没食子酸丙酯组〉充氮保护组〉色拉油组〉暴露于空气组〉0.02%Ca^2+组(P〈0.05)。75%c9,t11-CLA的氧化速度快于亚油酸(IJA)的氧化速度(P〈0.05)。结论:0.02%没食子酸丙酯可明显提高c9,t11-CLA的氧化稳定性。增强c9,t11-CLA的稳定性已成为保护c9,t11-CLA有效生物活性的至关重要的因素。 相似文献
4.
气相色谱分析法测定奶油中c9,t11-共轭亚油酸的含量 总被引:1,自引:0,他引:1
共轭亚油酸(conjugated linoleic acid,CLA)(以下简称CLA)是一类共轭双键位置在9和11或10和12的亚油酸(linoleic acid, LA)同分异构体的混合物,每个双键可以成顺式或反式构型[1],因而CLA最基本的空间构象是形成8种同分异构体[2].国外的大量研究表明,CLA具有很多重要的生物活性作用[3~10],如CLA具有抑癌作用、降低胆固醇和抗动脉粥样硬化作用、抗氧化作用,能有效地防止免疫刺激的分解代谢作用等,而c9,t11-CLA被认为是生物活性作用最强的共轭亚油酸异构体.目前,国内在CLA抑癌作用方面的研究已取得了很大的进展,但是关于食物中CLA含量的测定这一领域尚属空白.我们采用气相色谱内标法对奶油中c9,t11-CLA的含量进行定量测定. 相似文献
5.
c9,t11-共轭亚油酸对巨噬细胞因子表达的影响 总被引:6,自引:0,他引:6
目的 研究c9,t11-共轭亚油酸(Conjugated linoleic acid,CLA)对C57小鼠巨噬细胞杀伤黑色索瘤细胞(B16-MB)能力的影响。方法用0,25,50,75,100μmol/L CLA处理巨噬细胞24h后,分别用MTT法检测CLA处理的巨噬细胞对B16-MB细胞的杀伤能力;RT-PCR方法检测C57小鼠巨噬细胞细胞因子IL-6、TNF-α和iNOS mRNA表达。结果 在100,75μmol/L CLA处理后,巨噬细胞对肿瘤的杀伤率分别为18%和14.5%:同时,IL-6、TNF-α和iNOS mRNA表达增加。结论 c9,tll-CLA增强C57小鼠巨噬细胞对B16-MB细胞的杀伤能力,并与其诱导IL-6、TNF-α和iNOS mRNA的表达有关。推测CLA发挥抗肿瘤作用可能与其参与机体免疫调节作用有关. 相似文献
6.
目的 研究c9,t11-共轭亚油酸(c9,t11-CLA)抑制人胃腺癌细胞(SGC-7901)转移作用与亚油酸代谢途径中限速酶环氧合酶-2(COX-2)的关系。方法采用体外细胞培养方法,用COX-2的选择性抑制剂NS.398抑制SGC-7901细胞中COX-2的活性,再加入200、100、50和25μmol/L浓度的c9,t11-CLA,利用重组基底膜侵袭实验、黏附实验、趋向运动实验检测c9,t11-CLA抑制肿瘤细胞转移的作用与COX-2的关系。结果与NS-398组比较,NS-398+100Ixmol/Lc9,t11-CLA和NS-398+200μmol/L c9,t11-CLA对SGC-7901细胞的侵袭有明显的抑制作用,穿过膜的细胞数分别为48.7±1.5(F=14.309,P=0.000)和43.7±4.0(F=19.005,P=0.000);NS-398+200μmol/L c9,t11-CLA组能显著降低SGC-7901细胞对基质成分层粘连蛋白、纤维粘连蛋白和基质胶的黏附作用,所测吸光度值(A值)分别为0.052±0.011,0.058±0.008(F=3.063,P=0.021)和0.042±0.004(F=6.692,P=0.001;F=11.999,P=0.000);NS-398+200ixmol/L c9,t11-CLA对SGC-7901细胞的趋向运动能力无明显的抑制作用(F=1.380,P=0.276),其中NS-398+2001xmol/L c9,t11-CLA组细胞数为26.6±3.4。结论 c9,t11-CLA具有抑制SGC-7901细胞体外侵袭能力、黏附能力和趋向运动能力,这种抑制作用可能与COX-2途径有关。 相似文献
7.
共轭亚油酸对正常动物细胞和人体肿瘤细胞间通讯功能的影响 总被引:2,自引:0,他引:2
为探讨c9,t11-共轭亚油酸 (CLA)的抑癌作用可能机制 ,在促癌物 (TPA)存在下 ,对正常细胞(CHL)以及人体肿瘤细胞 (SGC 790 1细胞和MCF 7细胞 )的细胞间隙连接通讯功能 (GJIC)的影响 ,采用划痕标记染料示踪技术 (SLDT) ;c9,t11 CLA剂量为 2 5 (mol L ,5 0 (mol L ,10 0 (mol L和 2 0 0 (mol L ,阴性对照为乙醇。结果显示 ,c9,t11 CLA可明显地提高TPA对CHL细胞的GJIC的抑制效应 ,当c9,t11 CLA浓度为 2 0 0 (mol L作用 48h时 ,细胞间隙通讯功能基本上与阴性对照组相近 ;当用c9,t11 CLA作用SGC 790 1细胞和MCF 7细胞2 4h和 48h时 ,可见 (2 4h 10 0 μmol L的MCF 7细胞 ) 2 4h 2 0 0 μmol L和 48h 10 0、2 0 0 μmol L剂量组的肿瘤细胞有一定的细胞间隙通讯功能。提示c9,t11 CLA可提高SGC 790 1细胞和MCF 7细胞的GJIC的功能 ,并且不同程度的拮抗TPA对CHL细胞GJIC的抑制效应 相似文献
8.
目的 采用体外细胞培养方法,研究不同浓度c9,t11 共轭亚油酸对人胃腺癌细胞(SGC- 790 1)的亚油酸代谢途径中限速酶———环氧合酶(COX -2 )及其产物前列腺素E2 (PGE2 )的影响。方法 采用逆转录聚合酶链反应(RT- PCR)和Westernblot方法检测不同浓度c9,t11 CLA处理后的SGC 790 1细胞中COX- 2mRNA和蛋白的表达,放射免疫方法检测细胞分泌的PGE2 浓度。结果 在2 5、5 0、10 0和2 0 0 μmol L浓度时,c9,t11 CLA均可下调COX 2mRNA和蛋白的表达,同时降低细胞中PGE2 的分泌。结论 环氧合酶2是c9,t11 CLA抑制肿瘤细胞增殖的作用靶点。 相似文献
9.
共轭亚油酸诱导人乳腺癌细胞(MCF-7)凋亡的作用 总被引:4,自引:0,他引:4
目的 为了研究共轭亚油酸单体 (c9,t11 CLA)对人乳腺癌细胞 (MCF 7)凋亡的影响。方法 采用细胞生长曲线 ,凋亡细胞的荧光显微镜和电镜观察、流式细胞光度术的检测以及p5 3蛋白表达的方法 ,观察了用不同浓度c9,t11 CLA(2 5、5 0、10 0和 2 0 0 μmol L)诱导MCF 7细胞凋亡作用。结果 c9,t11 CLA可明显抑制MCF 7细胞生长 ,8天的抑制率分别为 -6 0 %、4 5 2 %、99 0 %和 99 4 %。通过荧光显微镜和电镜技术观察到了发生凋亡的MCF 7细胞 ;用流式细胞光度术也检测到c9,t11 CLA可诱导MCF 7细胞产生凋亡 ,并随着c9,t11 CLA浓度的增加 ,细胞凋亡率逐渐增加 ;而p5 3蛋白表达则随着c9,t11 CLA浓度的增加呈现逐渐降低的趋势。结论 c9,t11 CLA可诱导MCF 7细胞产生凋亡 ,这可能是c9,t11 CLA抑制肿瘤细胞生长的机制之一。 相似文献
10.
目的通过研究t10,c12-共轭亚油酸(t10,c12-CLA)对高游离脂肪酸环境中骨骼肌细胞脂肪酸代谢的影响,探讨t10,c12-CLA改善脂代谢的作用机制。方法体外培养成熟的C2C12骨骼肌细胞,通过施加软脂酸在体外模拟高游离脂肪酸环境,再给予不同浓度的t10,c12-CLA(20、30和40μmol/L),通过荧光免疫法利用激光共聚焦显微镜观察t10,c12-CLA对细胞脂肪酸转运蛋白(FAT/CD36)的影响,应用Western blot法检测t10,c12-CLA对C2C12细胞脂肪酸代谢相关酶及AMP激活的蛋白激酶(AMPK)的作用。结果t10,c12-CLA剂量依赖性的增加了高游离脂肪酸环境中细胞对脂肪酸的摄取,抑制了乙酰辅酶A羧化酶(ACC)的活性,增加了肉碱酰基转移酶-1(CPT-1)的表达,并且激活了AMPK。结论t10,c12-CLA可通过激活AMPK增强细胞对脂肪酸的氧化代谢。 相似文献
11.
Paula A. Lopes Susana V. Martins Mário S. Pinho Cristina M. Alfaia Carlos M.G.A. Fontes Pedro O. Rodrigues Graça S.L. Morais Matilde F. Castro Rui Pinto José A.M. Prates 《Nutrition Research》2008
Previous reports have demonstrated that conjugated linoleic acid (CLA) acts on body fat accumulation in a variety of animal models. The aim of the present study was to investigate the effect of cis (c)-9,trans (t)-11 and t10,c12 CLA isomers on the number and size of adipocytes from the inguinal and retroperitoneal fats in Wistar male rats. A 5.1% palm oil–based diet was supplemented with CLA isomers as follows: 0.6% of c9,t11, 0.6% of t10,c12, 1.3% of c9,t11 and t10,c12 isomers in mixture, and a control nonsupplemented group for comparative purposes. Fat tissues were prepared on microscope slides for histologic examination using an image-analysis software to count the number of adipocytes and measure cell sizes. The results showed that CLA isomers did not affect (P > .05) either final body and fat depot weights or serum lipids (with the exception of triacylglycerols) and adipocytokines (leptin and adiponectin). Animals fed the c9,t11 CLA isomer diet showed larger adipocytes when compared to other groups. Independently of the CLA dietary treatment, retroperitoneal fat showed larger adipocytes (3319 μm2) and therefore a smaller number of adipocytes per unit of area, compared to inguinal fat (3055 μm2). Taken together, the data suggest that a palm oil–based diet supplemented with the c9,t11 CLA isomer in Wistar rats, in contrast to the t10,c12 isomer and the mixture of both isomers, increases adipocyte dimensions in inguinal and retroperitoneal fat depots, while having a minor effect in serum lipids and adipocytokines. 相似文献
12.
Liu JR Chen BQ Yang YM Han XH Xue YB Wang XL Zheng YM Liu RH 《Environmental health and preventive medicine》2002,7(5):205-210
Objectives To determine the effect of cis-9, trans-11-conjugated linoleic acid on the cell cycle of mammary cancer cells (MCF-7) and
its possible mechanism of inhibition cancer growth.
Methods Using cell culture and immunocytochemical techniques, we examined the cell growth, DNA synthesis, expression of PCNA, cyclin
A, B1, D1, p16ink4a and p21cip/wafl of MCF-7 cells which were treated with various c9, t11-CLA concentrations (25 mM, 50 mM, 100 mM and 200 mM) of c9, t11-CLA
for 24 and 48 h, with negative controls (0.1% ethanol).
Results The cell growth and DNA synthesis of MCF-7 cells were inhibited by c9, t11-CLA. MCF-7 cells, after treatment with various
c9, t11-CLA doses mentioned above for 8 days, the inhibition frequency was 27.18%, 35.43%, 91.05%, and 92.86%, respectively
and the inhibitory effect of c9, t11-CLA on DNA synthesis (except for 25 mM, 24 h) incorporated significantly less3H-TdR than did the negative control (P<0.05 andP<0.01). To further investigate the influence on the cell cycle progression, we found that c9, t11-CLA may arrest the cell
cycle of MCF-7 cells. Immunocytochemical staining demonstrated that MCF-7 cells preincubated in media supplemented with different
c9, t11-CLA concentrations at various times significantly decreased the expressions of PCNA, and Cyclin, A, B1, D1 compared with the negative controls (P<0.01), whereas the expressions of p16ink4a and p21cip/wafl, cyclin-dependent kinases inhibitors (CDKI), were increased.
Conclusions The cell growth and proliferation of MCF-7 cells is inhibited by c9, t11-CLA by blocking the cell cycle, which reduces expressions
of cyclin A, B1, D1 and enhances expressions of CDKI (p16ink4a and p21cip/wafl). 相似文献
13.
Conjugated linoleic acid (CLA) is a polyunsaturated fatty acid that has numerous biologic activities. Previous studies in rodents demonstrated that chronic intake of CLA t10,c12 or CLA c9,t11 isomers perturbs the metabolism of retinoids (vitamin A and its derivatives). Specifically, although both isomers increased liver retinoid levels, only CLA t10,c12 also stimulated hepatic retinol secretion into the bloodstream. Given that retinoid homeostasis in mammalian serum and tissues is crucial to maintain health, it is important to gain more insights into the mode of action of this nutrient-nutrient interaction. Here we hypothesized that an acute administration of either CLA isomer may also influence vitamin A metabolism. By gavaging wild-type and retinol-binding protein knockout mice with an oral bolus of radiolabeled retinol containing 1 of these 2 isomers, we showed that both CLA t10,c12 and CLA c9,t11 rapidly enhance hepatic uptake of dietary vitamin A and its resecretion from the liver in the form of retinol bound to retinol-binding protein. Indeed, in mice lacking this protein, the sole specific carrier for retinol in the circulation, this latter effect was blunted. In addition, by using a pharmacologic inhibitor of the clearance of chylomicrons, which distribute recently ingested vitamin A and lipids throughout the body, we provided evidence that CLA intake might rapidly enhance intestinal absorption of dietary vitamin A. These data demonstrate the existence of multiple levels of interaction between dietary CLA and retinoid metabolism and warrant further studies to understand the molecular mechanisms underlying these effects and their implications for human health. 相似文献
14.
Yunkyoung Lee 《Nutrition Research And Practice》2008,2(4):326-330
Conjugated linoleic acids (CLA) were identified in 1980''s, since then it has been intensively studied due to its various beneficial health effects such as anti-inflammatory, anti-atherogenic, anti-carcinogenic and anti-diabetic/obesity effects. Isomer specificity of a number of CLA isomers, especially predominant isomer 9Z,11E- and 10E,12Z-CLA, is now recognized. However, the less prevalent CLA isomers have not been well characterized. Recently, studies have reported the distinctively different effects of 9E,11E-CLA in colon cancer cells, endothelial cells, and macrophage cells compared to the rest of CLA isomers. In this review, various effects of CLAs, especially anti-inflammatory and anti-atherogenic effects, will be discussed with focusing on the isomer-specific effects and potential mechanism of action of CLA. At last, recent studies about 9E,11E-CLA in in vitro and animal models will be discussed. 相似文献
15.
Quantitative determination of conjugated linoleic acid isomers by silver ion HPLC in ewe milk fat 总被引:2,自引:0,他引:2
José Luis Rodríguez-Castañedas María Jesús Peña-Egido Matilde García-Marino Concepción García-Moreno 《Journal of food composition and analysis》2011,24(7):1004-1008
The aim of this research was to validate a method for the quantification of conjugated linoleic acid (CLA) isomers in the fat of ewe's milk. The isomers in the form of methyl ester (FAME) are separated by silver ion high performance liquid chromatography (Ag+HPLC) and the quantification was based on the measurement of the integrated area under the 231 nm peaks, using external CLA reference standards. The response linearity is maintained in a wide range of concentrations and the quantification limit estimated was of 0.005 μg/injection for the cis-9,trans-11 and trans-10,cis-12 isomers. Referred to the samples this limit would be 0.008 mg/g of fat in the usual working conditions. In the precision assay an RSDr of 2.14% for the isomer cis-9,trans-11 was calculated and for the rest of the CLA isomers varied between 2.08 and 7.5%. The recovery assays were performed adding CLA cis-9,trans-11 triglyceride and the mean recovery was 96%. The method proposed allows the determination of the individual content of different CLA isomers using one single technique, HPLC and supposes saving time and resources. 相似文献