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排序方式: 共有85条查询结果,搜索用时 36 毫秒
1.
Purpose: Oxidative stress and systemic inflammation are the root cause of several deleterious effects of chronic psychological stress. We hypothesize that the antioxidant and anti-inflammatory capabilities of the macular carotenoids (MCs) lutein, zeaxanthin, and meso-zeaxanthin could, via daily supplementation, provide a dietary means of benefit.

Methods: A total of 59 young healthy subjects participated in a 12-month, double-blind, placebo-controlled trial to evaluate the effects of MC supplementation on blood cortisol, psychological stress ratings, behavioural measures of mood, and symptoms of sub-optimal health. Subjects were randomly assigned to one of three groups: placebo, 13?mg, or 27?mg / day total MCs. All parameters were assessed at baseline, 6 months, and 12 months. Serum MCs were determined via HPLC, serum cortisol via ELISA, and macular pigment optical density (MPOD) via customized heterochromatic flicker photometry. Behavioural data were obtained via questionnaire.

Results: Significant baseline correlations were found between MPOD and Beck anxiety scores (r?=??0.28; P?=?0.032), MPOD and Brief Symptom Inventory scores (r?=?0.27; P?=?0.037), and serum cortisol and psychological stress scores (r?=?0.46; P?P?Conclusions: Supplementation with the MCs significantly reduces stress, cortisol, and symptoms of sub-optimal emotional and physical health. Determining the basis for these effects, whether systemic or a more central (i.e. brain) is a question that warrants further study.  相似文献   
2.
目的:观察叶黄素(lutein)对叔丁基过氧化氢(t-BHP)处理的视网膜神经节细胞(RGC-5细胞系)的保护效应并探讨其作用机制。方法:用免疫荧光染色检测视网膜神经节特异性蛋白Brn-3和神经微管结合蛋白MAP-2的表达来鉴定RGC-5细胞;将RGC-5细胞随机分为对照组、t-BHP处理组、t-BHP和lutein共同处理组、lutein处理组,培养24 h,MTT实验检测细胞活力;Annexin V-FITC/PI双染流式细胞术检测细胞凋亡;免疫细胞化学技术检测caspase-3蛋白的活化情况;Western blot检测Bcl-2/Bax、cleaved caspase-3、JNK和c-Jun蛋白的变化。结果:MTT实验和流式细胞检测结果显示,lutein能提高t-BHP处理的RGC-5细胞的活力,并降低t-BHP诱导的RGC-5细胞凋亡;免疫荧光结果显示lutein能抑制t-BHP诱导的caspase-3的活化;与对照组比较,t-BHP处理后RGC-5细胞抗凋亡蛋白Bcl-2表达下调(P0.05),Bax/Bcl-2比率升高,cleaved caspase-3表达上调(P0.05),JNK和c-Jun蛋白的磷酸化水平增加(P0.05),t-BHP的上述作用可被lutein部分逆转。结论:Lutein能够降低t-BHP诱导的RGC-5细胞凋亡,其机制与其上调Bcl-2的表达、抑制caspase-3的活化并降低JNK和c-Jun蛋白的磷酸化有关。  相似文献   
3.
There is increasing interest by consumers, researchers, and regulators into the roles that certain bioactive compounds, derived from plants and other natural sources, can play in health maintenance and promotion, and even prolonging a productive quality of life. Research has rapidly emerged suggesting that a wide range of compounds and mixtures in and from plants (such as fruits and vegetables, tea and cocoa) and animals (such as fish and probiotics) may exert substantial health benefits. There is interest in exploring the possibility of establishing recommended intakes or dietary guidance for certain bioactive substances to help educate consumers. A key aspect of establishing dietary guidance is the assessment of safety/toxicity of these substances. Toxicologists need to be involved in both the development of the safety framework and in the evaluation of the science to establish maximum intake/upper limits.  相似文献   
4.
目的:建立C30-高效液相色谱(high performance liquid chromatography,HPLC)内标法测定血清叶黄素、玉米黄素和β-胡萝卜素。方法:应用Develosil C30-UG色谱柱(250 mm×4.6 mm,5μm),流动相A为乙腈∶甲醇(体积比60∶40),流动相B为甲基叔丁基醚,梯度洗脱。流速1 mL/min,检测波长450 nm,进样量20μL,柱温25℃。内标物为全反式-β-阿扑-8'-胡萝卜醛。结果:血清叶黄素、玉米黄素和β-胡萝卜素的分离效果良好,保留时间分别为9.9min、10.3 min和21.2 min,日内相对标准差分别为3.22%、3.81%和1.60%。血清叶黄素、β-胡萝卜素在0.012 5~12.5 mg/L(r=0.999 5、r=0.999 7),玉米黄素在0.005~5.0 mg/L(r=1)范围内呈良好线性关系。58名正常老年人(年龄50岁)血清叶黄素、玉米黄素和β-胡萝卜素的平均浓度分别为0.410μmol/L、0.054μmol/L和0.128μmol/L。结论:该C30-HPLC内标法是定量分析血清叶黄素、玉米黄素和β-胡萝卜素的可靠方法之一。  相似文献   
5.
高效液相色谱法测定保健食品中的叶黄素   总被引:2,自引:0,他引:2  
目的:建立测定保健食品中叶黄素含量的方法。方法:采用无水乙醇对试样进行提取,纯甲醇体系作为流动相,ODS C18柱,高效液相色谱(HPLC)进行分离检测。结果:方法的检出限为0.1μg/g,线性范围在0.3μg/ml~6.2μg/ml之间,RSD为5.9%,平均回收率为92%~105%。结论:该方法具有简便、快速、可靠、容易推广等优点,适用于液体、片剂、粉剂、胶囊、软胶囊样品的测定。  相似文献   
6.
目的 探讨经阴道彩色多普勒超声对妊娠卵巢黄体和宫外孕的鉴别诊断。方法 测量经病理证实的50例宫外孕患者附件包块的大小、血流频谱及50例早孕合并卵巢黄体患者的黄体大小及血流频谱。测量的血流频谱参数包括搏动指数(PI)、阻力指数(RI)和胎儿脐动脉收缩压与舒张压的比值S/D。结果 宫外孕包块大小不等;卵巢黄体上下径(17.28±2.70)mm、前后径(15.18±3.15)mm、左右径(17.06±3.79)mm;妊娠卵巢黄体超声表现为低回声型、厚壁囊型、薄壁囊肿内部回声型;宫外孕包块超声表现为妊娠囊型、复杂型。经阴道彩色脉冲多普勒测及卵巢黄体的各血流参数均低于宫外孕包块(P<0.05);宫外孕包块血流频谱表现多样,卵巢黄体多呈单向血流频谱。结论 经阴道彩色多普勒超声对鉴别妊娠卵巢黄体及宫外孕有重要临床价值。  相似文献   
7.
目的 探究叶黄素对人前列腺癌PC3细胞增殖和凋亡影响的作用机制,为前列腺癌预防及治疗提供新的理论依据。方法 不同浓度叶黄素作用于PC3细胞,CCK8法检测细胞增殖情况;流式细胞仪检测细胞周期分布和凋亡变化;细胞划痕和Transwell实验观察细胞迁移和侵袭能力;RT-PCR和Western blot技术检测细胞中Bax、Bcl-2的mRNA水平和蛋白表达。结果 叶黄素显著抑制PC3细胞的增殖,并呈时间和浓度依赖性。叶黄素可以将细胞生长阻滞在G0/G1期,抑制细胞迁移和侵袭;还可促进细胞凋亡,使Bcl-2表达下降,Bax表达上升。叶黄素可在转录水平上下调Bcl-2 mRNA和上调BaxmRNA。结论 叶黄素抑制PC3细胞增殖并促进其凋亡,其机制可能与阻滞细胞周期、抑制细胞迁移、侵袭以及调节凋亡相关基因和蛋白表达有关。  相似文献   
8.
目的:建立高效液相色谱法同时测定奶粉中的叶黄素(Lut)、α-胡萝卜素(α-C)和β-胡萝卜素(β-C)的测定方法。方法:样品经皂化、石油醚-乙醚(1∶1)提取、水洗和浓缩后,以含2%水的甲醇-乙腈混合液(25∶75)和叔丁基甲基醚为流动相,在Waters C30柱中分离,二极管阵列检测器检测,外标法定量。结果:上述3种胡萝卜素在0.05μg/ml~4μg/ml范围内有良好的线性,相关系数R2均大于0.998,三水平加标平均回收率在80%~104%之间,每个加标水平的6次重复试验RSD<7.7%。结论:该方法可同时测定奶粉中的叶黄素、α-胡萝卜素和β-胡萝卜素含量,方法简便、快速、准确。  相似文献   
9.
叶黄素对人食管鳞癌细胞诱导分化效应与机制探讨   总被引:1,自引:0,他引:1  
目的 探讨叶黄素对食管癌EC9706 细胞诱导分化的影响及其机制.方法 食管癌EC9706细胞采用开放式单层贴壁培养.实验设溶剂对照及叶黄素3个剂量组,采用MTT法及流式细胞术,对EC9706 细胞的增殖和细胞周期进行分析,HE染色对细胞的形态学进行观察,酸解DNA甲绿-派洛宁技术了解增殖与分化型细胞比例,免疫组化检测cyclin D1的表达.结果 与溶剂对照组比较,叶黄素(100 μg/mL和150 μg/mL)可明显抑制EC9706 细胞的增殖,阻滞细胞周期于G0/G1期, 降低细胞增殖指数,细胞形态趋向良性分化,cyclin D1 表达水平降低.结论 叶黄素可通过抑制cyclin D1 表达而介导食管癌EC9706细胞增殖抑制和诱导成熟分化.  相似文献   
10.
Despite its serious adverse effects, recent accumulating evidence suggests that a physiological retinoic acid receptor (RAR) agonist, all-trans retinoic acid (atRA), exhibits preventive effects on atherogenesis. Therefore, the present study was designed to explore novel natural RAR ligands with anti-atherogenic effects in order to identify and develop a drug without severe side effects. Among xanthophylls and carotenoids studied, beta-cryptoxanthin and lutein exhibited RAR ligand activity in yeast two-hybrid system that was found to be completely abolished by the RAR pan-antagonist LE540. Furthermore, these molecules can bind the RAR ligand-binding domain in the CoA-BAP system but not RXR ligand-binding domain. These results indicate that both beta-cryptoxanthin and lutein serve as ligands for RAR, but not RXR, although their binding affinity was three orders of magnitude lower than that of atRA. Additionally, when applied to macrophages, beta-cryptoxanthin indeed was found to induce the ATP-binding cassette transporter A1 (ABCA1) and ABCG1 mRNAs, which exert anti-atherosclerotic effects by preventing cholesteryl ester accumulation in macrophages. The induction of ABCA1 proteins by beta-cryptoxanthin as well as atRA was abrogated by LE540. In summary, beta-cryptoxanthin appears to be more an efficient provitamin A source than other carotenoids and xanthophylls including beta-carotene, since beta-cryptoxanthin can act not only as a RAR agonist but also a source of vitamin A. Taking into account that the pharmacodynamics difference between beta-cryptoxanthin and atRA, beta-cryptoxanthin appears to exert beneficial effects on atherogenesis through RAR activation in the manner different from atRA.  相似文献   
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