莪术多糖的分离提取及其生物学活性研究

目的:从莪术饮片中分离多糖,并研究其生物学活性。方法:莪术饮片的热水浸提液经浓缩、醇析、活性碳吸附除色素、Savage 法除蛋白得其粗多糖,经DEAE-52柱层析,分离各组分。苯酚-硫酸法测多糖含量。采取腹腔注射与口服两种途径在小鼠测其生物学活性。结果:莪术饮片中总糖的含量为33.12%,多糖提取率为1.938%。莪术多糖可以提高小鼠的脾指数、淋巴细胞转化率;提高血液中超氧化物歧化酶的活力;具有抑瘤作用;体外具有抗羟自由基的能力。腹腔注射时抑瘤率明显高于口服途径,并呈现剂量依赖性。结论:莪术多糖可以提高小鼠的免疫调节能力,表现出抗氧化活性;并具有较高的抗H22肝癌腹水瘤的能力。     

芝麻素生物学活性研究进展

天然植物的现代药理研究是目前国内外医学研究热点^〔1〕。芝麻在我国资源丰富,长久以来,一直被视为滋补圣品,具有“补肝肾、润五脏、增气力、消炎止痛、生发”等功效。芝麻中的主要活性成分为木脂素类,主要包括芝麻素(Sesa-min)和芝麻林素,其中芝麻素约占总木脂素类含量的50%左右,在体内表现出较强的生物学活性^〔2〕,其药物作用近年逐渐被人们所重视。现将芝麻素的生物学活性研究进展综述如下。     

叶下珠属植物生物学活性研究近况

叶下珠属植物生物学活性研究近况陈锦综述郭维新审校目前，天然药用植物的研究和利用已引起世界各国的广泛重视。虽然我国利用植物防病治病的历史悠久，但对其生物学活性和有效成份缺乏系统的研究，而对此深入的探讨，将有利于自然资源的开发和利用，也将为疾病的治疗提供...     

中国螺旋藻产业战略联盟在京成立：中国螺旋藻产业战略联盟螺旋藻标准与检测方法

2006年12月20日，在国家发改委公众营养与发展中心、中国食品工业协会指导下，由云南绿A生物工程有限公司、福建福清新大泽螺旋藻有限公司、云南施普瑞生物工程有限公司共同组成的“中国螺旋藻产业战略联盟”在京隆重成立。这标志着中国螺旋藻产业的第一个规范性组织机构正式成立，意味着中国螺旋藻产业将告别无规范、无标准的无序竞争状态。联盟的成立将对中国螺旋藻产业的良性发展具有里程碑的意义。[编者按]     

螺旋藻中胡萝卜素半衰期实验研究

[目的 ]探讨螺旋藻主要成分胡萝卜素的半衰期与预测方法。 [方法 ]应用加速储存实验 ,观测不同温度下胡萝卜素含量变化的规律。 [结果 ]采用线性回归拟合方程 lny=6 .2 6 74- 0 .0 76 15 x (y为半衰期 ,x为储存温度 )和Arrhenius经验公式 Qi=2 .12 5 75 (50 - ti) /1 0 × 11.70 (ti为储存温度 ,Qi为半衰期 )推算任意温度下的半衰期 (d) ,两种方法计算结果很接近。 [结论 ]螺旋藻中胡萝卜素半衰期预测用线性回归方程法 ,比 Arrhenius经验公式推算结果 ,更加简单和稳定。     

海参的营养成分及海参多糖的抗肿瘤活性的研究

海参为海味珍品 ,可与人参媲美。我国古代文献《随息居饮食谱》、《本草从新》、《本草纲目拾遗》等都对海参的保健功能及药用价值有所记载。全世界有海参 1 1 0 0余种 ,有不同的形态和生态习性 ,多数海参栖息于温带或亚热带的波静水流稳、海藻茂密的岩礁或珊瑚礁海域。由于这些海参的生活环境不同、所食物质各异 ,所以其营养物质的多少存在差异 ,本研究分析不同海域三种海参的营养成分 ,为进一步开发利用海参提供科学根据。1　材　料　与　方　法1 .1　材料　　红参 ( H olothuria.sp)取于美国红参干粉 ;海茄子 ( Cucumaria cucumaria)取…     

螺旋藻类保健食品中核黄素的检测方法研究

目的建立螺旋藻类保健食品中核黄素测定的高效液相色谱（HPLC）法。方法样品直接在恒温干燥箱121℃、30min酸水解,再经混合酶液酶解后进行HPLC分析,经C18柱分离,以甲醇和乙酸钠为流动相,用荧光检测器检测,外标法定量。结果该方法检出限为0.2mg/kg,线性范围0-2.0mg/L,加标回收率为86.3%-94.0%。结论该法操作简便、准确可靠,适用于螺旋藻类保健食品中核黄素的测定。     

端粒酶生物学作用及活性调节

自Blackbum等在二十世纪八十年代先后发现了端粒、端粒酶以后，对它的研究已成为肿瘤学、毒理学、生殖遗传学等研究领域的热门课题。现已证明：端粒酶是一种由RNA和蛋白质组成的核糖核蛋白复合体，具有逆转录酶活性。它在正常组织细胞中不表达，仅在生殖细胞、干细胞、肿瘤细胞中表达。许多研究表明，端粒酶与细胞增殖、细胞衰老和生殖功能的稳定关系密切，因此近十多年来，     

海地瓜的营养成分及其降血脂功能

目的分析海地瓜的营养成分,探讨其降血脂功能。方法用高效液相色谱等技术分析了海地瓜的营养成分并同刺参进行了比较。以高脂饲料喂养雄性SD大鼠,建立高脂血症模型,观察海地瓜对肝指数和脂肪系数的变化情况及大鼠血脂水平、血清抗氧化功能的影响。结果海地瓜粗脂肪含量明显低于刺参,仅为0.43%,氨基酸含量丰富,包含人体所需的8种必需氨基酸,所测氨基酸中大部分含量高于刺参。海地瓜能显著降低大鼠肝指数和脂肪系数,能显著降低饲喂高脂饲料大鼠血清总胆固醇(TC)、甘油三酯(TG)、低密度脂蛋白胆固醇(LDL-C)、动脉硬化指数(LDL-C/HDL-C)水平,升高高密度脂蛋白胆固醇(HDL-C)和动脉硬化指数(HDL-C/TC)值;能提高血清谷胱甘肽过氧化物酶(GSH-Px)的活性,并能降低血清丙二醛(MDA)和游离脂肪酸(NEFA)含量。结论海地瓜氨基酸含量丰富,粗脂肪含量低,具有调节降低血脂水平和增强抗氧化功能的作用,可减少高脂膳食导致的氧化损伤。它是一种非常好的保健品原料,在某些方面可替代目前价位最高的刺参。     

螺旋藻中氨基酸含量水平测定及其营养保健价值

目的:研究螺旋藻中各种氨基酸含量及其营养保健价值。方法:用氨基酸分析仪检测螺旋藻中各种氨基酸的组成。结果:螺旋藻中含有赖氨酸、天门冬氨酸、胱氨酸、谷氨酸、苯丙氨酸、苏氨酸、色氨酸、缬氨酸等18种氨基酸,氨基酸总含量为55.20%;其中人体必需氨基酸总含量为25.83%;非必需氨基酸总含量为29.37%;必需氨基酸含量占总氨基酸含量的46.79%;必需氨基酸与非必需氨基酸之比为87.95%。结论:表明螺旋藻在营养学上有一定的研究价值与保健功效,具有很好的开发应用前景。     

倍半萜类化合物生物活性研究进展

倍半萜广泛存在于植物、海洋生物及某些昆虫、菌类中。虽然骨架仅有15个碳原子,但由于生物体内微妙的代谢过程而生成形形色色的基本骨架的化合物,并有复杂的立体结构,具有抗肿瘤、抗炎、抗菌消炎、抗神经毒性、抗虫活性和昆虫拒食作用,还有免疫抑制活性、抗病毒、保肝、强心活性、抑制组胺和乙酰胆碱、降血脂和调节植物生长作用。作者以国内外文献为依据,从植物来源、生物活性方面综述倍半萜类化合物及衍生物的研究进展。     

膳食营养素与高尿酸血症关系的研究进展

目的 综述各类膳食营养素与高尿酸血症（HUA）关系的研究进展。方法 以“膳食”、“营养素”和“高尿酸血症”作为CNKI数据库和万方数据库的检索词,以“diet”、“nutrients”和“hyperuricemia”作为PubMed数据库的检索词,参考文献33篇。结果 高嘌呤食物、维生素、蛋白质、脂肪、碳水化合物、矿物质、酒精等膳食营养素的摄入与HUA密切相关。结论 应根据各危险因素合理调整各营养素的摄入,以提高HUA患者的生存质量,加强健康膳食模式的推广和普及。     

膳食营养素对砷毒性的影响

环境砷暴露是一个世界范围内的公共卫生问题,长期接触无机砷与心血管疾病、糖尿病以及恶性肿瘤等疾病关系密切。膳食结构的不同以及某些特定营养素的摄入对砷的致病效应可能产生重要影响。本文概述了膳食营养素对砷毒性的影响,为后续砷毒性研究以及通过营养干预来降低与砷有关的疾病风险提供参考。     

Blood and urinary benzene determined by headspace gas chromatography with photoionization detection: application in biological monitoring of low-level nonoccupational exposure

A simple and sensitive gas chromatography (GC) headspace method was developed for the determination of benzene in blood and urine. 1.0 ml of venous blood or urine sample in a headspace vial containing chlorobenzene as an internal standard was incubated at 60°C for 30 min and 0.5 ml headspace gas was used for GC analysis. Unmetabolized benzene in blood or urine was detected at 2.5 min using a silicone gum capillary column and a photoionization detector. The proposed method appears to be more sensitive and reliable than other existing methods, with recovery and reproducibility generally over 90% and a detection limit of 0.64 and 0.51 nmol/l for blood and urinary benzene, respectively. The proposed method was validated with blood and urine samples collected from 25 nonsmokers and 50 smokers. The blood and urine concentrations of benzene in nonsmokers were significantly lower (P < 0.001) than those in smokers: the mean concentrations for blood and urinary benzene, respectively, were 1.42 and 4.21 nmol/l for nonsmokers and 1.49 and 5.19 nmol/l for smokers. A significant correlation (r = 0.61, P < 0.001) was also found between benzene in blood and benzene in urine. These findings suggest that benzene in urine as well as benzene in blood can be used for the biological monitoring of low levels of benzene exposure. Although there was a close correlation between benzene in blood and benzene in urine, no correlation was found between benzene in blood or benzene in urine and the number of cigarettes smoked.     

Effect of simultaneous exposure to toluene and xylene on their respective biological exposure indices in humans

Summary Studies that specifically address the influence of controlled human exposure to a combination of solvents on the biological monitoring of exposure are limited in number. The present study was undertaken to investigate whether simultaneous exposure of human volunteers to toluene and xylene could modify the respective metabolic disposition of these solvents. Five adult Caucasian men were exposed for 7 consecutive h/day over 3 consecutive days to 50 ppm toluene and 40 ppm xylene either separately or in combination in a dynamic, controlled exposure chamber (low-level exposure). The experiment was repeated three times at intervals of 2 weeks. In another experiment, three subjects were exposed to 95 ppm toluene and 80 ppm xylene or a combination of both for 4h (high-level exposure). The concentration of unchanged solvents in blood (B) and in end-exhaled air (EA) as well as the urinary excretion of hippuric acid (HA) and methylhippuric acids (MHAs) were determined. Simultaneous exposure to the lowest level of solvents did not alter the concentration of unchanged solvents in blood or in exhaled air (average of 3-weekly means; single vs mixed exposure at 6.5 h exposure): B-toluene, 77.1 vs 78.1 g/100 ml; B-xylene, 67.6 vs 77.8 g/100 ml; EA-toluene, 9.9 vs 9.5 ppm; EA-xylene, 5.3 vs 4.8 ppm. Similarly, mixed exposure did not modify the excretion of urinary metabolites during the 3- to 7-h exposure period: HA, 1.11 vs 1.11 g/g creatinine; MHAs, 0.9 vs 0.87 g/g creatinine. However, simultaneous exposure to higher levels did affect the concentration of unchanged solvents in blood and in exhaled air as measured at 3.5 h exposure (mean value for three subjects ± SD): B-toluene, 135.7 ± 26.7 vs 215.7 ± 34.9 g/100 ml; B-xylene, 114 ± 19 vs 127.6 ± 22.1 g/100 ml; EA-toluene, 16.6 ± 0.4 vs 20.5 ± 2.8 ppm; EA-xylene, 9.9 ± 0.6 vs 12.3 ± 1.2 ppm. Such effects were accompanied by a significant delay in the urinary excretion of HA but not of MHAs. These data suggest that there is a threshold level below which metabolic interaction between toluene and xylene is not likely to occur in humans.     

营养素和食物成分的风险-收益评估

风险-收益评估是对某种物质/行为的风险和收益进行综合评定的一种方法。当某物质/行为对人类健康既可能有益又可能有害时,就需要对其风险与收益同时进行定性/定量比较。本综述系统介绍风险-收益评估的概念、步骤与适用场景,以及营养素/食物(成分)的风险-收益评估的常用模型及其应用等,并进一步提出该研究领域的若干挑战与展望。     

Structure activity relationship of some 2,3-diaryl-2H-1-benzopyrans to their anti-implantation, estrogenic and antiestrogenic activities in rat

In an endeavour to develop potent anti-implantation agents, a new antiestrogen, CDRI 85/287 (2-(4-2-piperidinoethoxy)phenyl-3-phenyl(2H)benzo(b)pyran), virtually devoid of agonistic activity, was identified. The present study deals with anti-implantation and estrogen agonistic-antagonistic activities of four structural analogues of 85/287. Results show that none of the compounds induced vaginal cornification, even at doses as high as 2.5 mg/kg. Compounds having p-hydroxyphenyl group at position-3 or hydroxy group at position- 7 showed better estrogen receptor affinity (6.6 and 25.3% E₂) as well as antiestogenic activity. When 3-p-hydroxyphenyl was replaced by 3-p-methoxyphenyl, a marked reduction in the receptor affinity was observed. However, this compound was relatively more potent as an anti-implantation agent, possibly due to its conversion to hydroxylated metabolite in vivo. The provision of aminoethoxy side chain at para-position and a shift in the piperidinoethoxy side chain from position-4 to position-2 in these molecules resulted in a decrease in estrogenicity and increase in antagonistic property. Results are discussed with regard to molecular configuration, relative binding affinity of these compounds to their biological profile.     

干法消化-原子荧光光谱法同时测定螺旋藻粉中砷和锑

目的建立干法消化和氢化物发生—原子荧光光谱法同时测定螺旋藻粉中砷和锑的方法。方法将螺旋藻粉干法消化后,利用氢化物发生—原子荧光光谱法同时测定砷和锑。对仪器条件进行了优化,比较了不同还原剂的增敏效果,考察了常见干扰离子对测定的影响。结果采用本方法测定,砷的线性范围为0～10μg/L,γ=0.9992,DL=0.16μg/L,回收率为96.0%～111.2%,精密度(RSD%)为2.37;锑的线性范围为0～10μg/L,γ=0.9998,DL=0.11μg/L,回收率为90.2%～109.0%,精密度(RSD%)为5.91。结论测定方法简单快捷,省时省力省试剂,结果准确,满足测定要求。     

Synthesis and biological activity of some new benzoxazoles

The synthesis and antimicrobial activity of a new series of 5-ethylsulphonyl-2-(substituted-phenyl/substituted-benzyl and/or phenylethyl)benzoxazole derivatives (3a-3t) except 3a, 3g, 3h, 3k [R.S. Pottorf, N.K. Chadha, M. Katkevies, V. Ozola, E. Suna, H. Ghane, T. Regberg, M.R. Player, Tetrahedron Lett. 44 (1) (2003) 175] were described. The in vitro antimicrobial activity of the compounds was determined against some Gram-positive, Gram-negative bacteria, a fungi Candida albicans and their drug-resistant isolates in comparison with standard drugs. Antimicrobial results indicated that the synthesized compounds possessed a broad spectrum of activity with MIC values 250-7.81 microg/ml. While all compounds are less potent than fluconazole against C. albicans, most of them are more potent than fluconazole against C. albicans isolate.