不同谷物籽粒中脂肪酶活性的比较

用改进的铜皂法和放射性分析法对小麦、燕麦和大麦籽粒中的脂肪酶活性进行了研究。发现燕麦的脂肪酶活性显著地大于大麦和小麦的。有迹象表明,燕麦水解生成的脂肪酸会进一步发生降解反应。虽然被燕麦脂肪酶游离出来的多重不饱和脂肪酸的还原产物有发生氧化反应的可能,但是无论小麦还是燕麦的脂肪酶都丝毫没有显示出底物的专一性。本文比较详细地阐述了小麦脂肪酶的分布部位和来源。在室温条件下分析结果表明,虽然大部分活性(75％—80％)分布在籽粒麸皮中,但胚芽中也存在显著的活性(20％—25％)。活性的相对分布比例与温度有关,于75℃条件下培育的面粉各组分中有几乎同等的脂肪酶活性。温度稳定性研究结果表明,面粉2种组分中存在着各自独立的脂肪酶。另外,本研究还得到了微生物污染对小麦总脂肪酶活性影响的直接或间接的证据。     

人参(西洋参)抑制胰脂肪酶活性及其抗肥胖作用

肥胖可引发身体多种代谢异常,造成高血脂症、糖尿病、心脑血管疾病、高血压、动脉粥样硬化、脂肪肝,严重危及人类健康。胰脂肪酶,是水解膳食脂肪的最重要的酶,可水解50%～70%的食物脂肪。通过抑制胰脂肪酶活性可以控制高脂饮食引起的肥胖。人参和西洋参能够抑制胰脂肪酶活性,降低高脂饮食小鼠体重、脂肪组织的重量、血脂和肝脂的作用。本文综述了近年来不同部位的人参及西洋参、不同种类人参皂苷抑制胰脂肪酶活性及其抗肥胖方面的作用。     

籼稻脂肪酶基因的遗传分析及定位

对籼稻材料PT46（高脂肪酶活性）和WP20（低脂肪酶活性）及其F2群体进行了脂肪酶活性的定量测定和遗传分析。χ2测验结果表明,F2群体表现型分布符合1∶2∶1的孟德尔分离比,表明脂肪酶活性高低由1对单基因控制,低脂肪酶活性为隐性性状。结合SSR分子标记,以F2群体为定位群体,将脂肪酶活性基因定位在水稻第3染色体上,与SSR标记RM7和RM232之间的遗传距离分别为14.8 cM和4.1 cM,暂命名为la（lipase activity）。采用人工老化的方法,以种子发芽率和老化指数评价两亲本及其F2群体的耐储藏特性,结合所测定的脂肪酶活性数据进行相关性分析。结果表明,随着老化时间的延长,脂肪酶活性高的材料,发芽率降低迅速,老化指数增加很快,而脂肪酶活性较低的材料,老化指数变化相对较慢,即脂肪酶活性低的材料较耐储藏。经10、20 d人工加速老化处理后的种子老化指数与种胚脂肪酶活性的相关系数分别为0.6165**和0.4703**,表明老化指数与脂肪酶活性呈显著正相关。     

陈年乌龙茶的生化成分及其降脂降糖活性研究

对黄金桂、岭头单丛和大叶奇兰三个茶树品种的陈年乌龙茶的茶多酚、儿茶素、氨基酸、可溶性糖等生化成分的含量进行测定,并分别比较其体外抗氧化及抑制α-淀粉酶与胰脂肪酶的活性。结果表明:三个品种的陈年乌龙茶的茶多酚、儿茶素和氨基酸含量均表现为2016年比1990年高,没食子酸含量则相反,水浸出物、可溶性糖、黄酮类和咖啡碱含量没有明显规律。体外总抗氧化能力结果显示,岭头单丛和大叶奇兰陈年乌龙茶表现为2016年比1990年高,黄金桂则差别不大;三个品种的乌龙茶陈茶体外抑制α-淀粉酶和胰脂肪酶活性均表现为2016年比1990年高。灰色关联度分析结果表明,陈年乌龙茶茶多酚的总抗氧化能力(关联系数0.6292)和抑制α-淀粉酶活性(关联系数0.3136)贡献最大,而茶多糖对抑制胰脂肪酶活性(关联系数0.4715)贡献最大。     

天然抗氧化物质的保健功能及抗氧化活性研究进展

人体的衰老和各种疾病的发生与体内氧化与抗氧化反应动态平衡被打破有关,各种天然的抗氧化物质对于维持这种平衡起到很好的保健功效.测定各种天然抗氧化物质抗氧化活性的方法有很多,通过比较发现铁离子还原法(ferric reducing/antioxidant power assay,FRAP)是一种简单、有效的方法,值得推广.     

茯砖茶不同萃取物对消化酶活性的影响

将茯砖茶依次用三氯甲烷、乙酸乙酯及正丁醇萃取后制备样品,测定各部分样品对α-淀粉酶及胰脂肪酶活性的影响。研究发现茯砖茶各部分样品对胰脂肪酶活性的影响程度不同,三氯甲烷层稍有抑制作用,活性只有对照的0.82倍,水提物、乙酸乙酯萃取层及正丁醇萃取层有显著的激活作用,正丁醇萃取层部分激活作用最明显,达2.54倍。茯砖茶各部分样品对α-淀粉酶活性均有激活作用,其中以乙酸乙酯萃取层部位的激活作用最强,激活倍数为4.09,其次是水提物,其激活倍数为2.99,水层的激活作用不显著。三氯甲烷萃取层抑制作用不显著,活性只有对照的0.88倍。乙酸乙酯萃取层及正丁醇萃取层部分经过HP-20树脂再分离后,各部分仍有较高的活性。     

六堡茶茶褐素体外降脂功效研究

考察六堡茶茶褐素体外结合胆酸盐能力、抑制胰脂肪酶活性及胆固醇酯酶活性能力、吸附胆固醇及油脂能力,从而评价其体外降脂活性。研究结果显示,六堡茶茶褐素对花生油的吸附量为0.73 g·g^-1,对胆固醇的吸附量在酸性条件下为122.42 mg·g^-1、中性条件下为13.68 mg·g^-1;在茶褐素结合胆酸盐的试验中,随着茶褐素浓度的增加,与胆酸盐结合能力也呈上升趋势;茶褐素对胰脂肪酶起激活作用,且随着浓度的增加呈持续上升趋势;对胆固醇酯酶活性抑制IC₅₀值为57.2 mg·mL^-1。六堡茶茶褐素降脂机制可能主要通过与胆酸盐结合、吸附胆固醇和脂肪来实现。     

儿茶素单体EGC对胰脂肪酶的抑制作用及其机理研究

为研究儿茶素单体表没食子儿茶素（Epigallocatechin,EGC）对胰脂肪酶的抑制作用及机制,以干燥绿茶为原料,采用热水提取法、三氯甲烷脱色素和柱层析分离,得到EGC单体。采用扫描电子显微镜、傅里叶红外光谱、核磁共振氢谱对纯化的EGC单体进行结构表征,再通过滴定法研究EGC对胰脂肪酶的抑制作用及类型,然后通过荧光光谱法以及分子对接技术表征了EGC对胰脂肪酶结构的影响。结果表明,EGC以非竞争性方式对胰脂肪酶表现出抑制作用,并且抑制效果随EGC浓度的增加呈持续上升趋势,半抑制浓度为(1.62±0.085) mg·mL^-1。EGC对胰脂肪酶有荧光猝灭作用,可通过分子间氢键和疏水相互作用与酶中的氨基酸残基结合,导致酶的化学结构和空间构象发生变化,从而降低酶活性。EGC主要通过改变胰脂肪酶的化学结构和空间构象来抑制该酶活性,从而达到降血脂功效。     

乌龙余甘茶的研制

乌龙余甘茶是一种以马龙茶和余甘果为原料；出取条与果小的有效成分，经科学配制而成的一种新型的天然营养、方便的固体饮料．乌龙茶是一种天然饮料，含有多种有益人体健康的营养成分。具有醒脑提神、消暑止渴助消化，抗衰老防癌等功效。余甘果则是一种具味酸甜可食，食始酸涩后甘润的水果。经北农大食品科学系检测，余甘果富含维生素A、B、C、PR人体所需的各种氨基酸、有机酸和矿物质。VC含量特高，在370、1416。g／100克。且VC具有高度稳定性和耐热性，受热破坏．还含有人体所需的微量元素如Se等．金甘果还含有人体抗衰老的有效物质之…     

信息窗

21世纪将是碱性饮料的世界据国家饮料行业权威机构预测，21世则将是碱性饮料的世界。何为碱性饮料呢？在时常生活中人们所接触的食物，就其生物化学性质而言，可分为弱大类：一类是成酸性食物，如肉类、鱼类、蛋类、谷类等，由于其中所含硫磷矿物质较多，在人体中的最终代谢产物是酸性；另一类是成碱性食物含钾、钠、钙、镁等矿物质较多，在人体代谢最终产物里碱性，如蔬菜、水果、乳类以及某、咖啡等．而健康人体的血液是微碱性的，如果你不时补充一些碱性饮料与碱性食物就有利于人体对蛋白质的吸收和利用．反之，倘若过多摄人肉，禽、蛋等…     

Isolation and properties of lipolysis inhibitory proteins from wheat germ and wheat bran

Proteins inhibiting pancreatic lipasein vitro have been isolated from wheat germ and wheat bran, with relative molecular mass ranging from 24,400 to 27,500. Inhibition of pancreatic lipase by the wheat germ proteins is related to their ability to interact with the emulsified substrate and to hinder the adsorption of the enzyme on the interface. The extent of inhibition depends on the amount of substrate and is independent of the enzyme concentration. Bile salts forming micelles in the concentration range used are able to partially reverse the inhibition of pancreatic lipase by the wheat germ proteins. The nutritional significance of the data obtained is discussed.     

Microbial Oligosaccharides with Biomedical Applications

Microbial oligosaccharides have been regarded as one of the most appealing natural products attributable to their potent and selective bioactivities, such as antimicrobial activity, inhibition of α-glucosidases and lipase, interference of cellular recognition and signal transduction, and disruption of cell wall biosynthesis. Accordingly, a handful of bioactive oligosaccharides have been developed for the treatment of bacterial infections and type II diabetes mellitus. Given that naturally occurring oligosaccharides have increasingly gained recognition in recent years, a comprehensive review is needed. The current review highlights the chemical structures, biological activities and divergent biosynthetic origins of three subgroups of oligomers including the acarviosine-containing oligosaccharides, saccharomicins, and orthosomycins.     

Effects of raw soy flour feeding in weanling pigs: comparison with rats and monkeys

Feeding of raw and heated soy flour (RSF & HSF) for 4 or 8 weeks to weanling swine was compared with feeding of casein diets. There was essentially no growth in pigs fed RSF, whereas body weight increased 4.5 fold over 8 weeks with either casein or HSF. No change in pancrease weight as percent body weight was found in any group in either experiment. Both total pancreatic RNA and DNA were decreased in RSF groups, although RNA and DNA/mg pancreas were increased by the RSF diets. Total pancreatic protein, as well as protein/mg, were decreased in RSF-fed pigs compared to casein and HSF. Pancreatic trypsin, chymotrypsin, lipase, and amylase, and fecal trypsin were decreased in RSF-fed pigs to varying degrees compared to either HSF or casein. HSF and casein performance was equivalent in all parameters measured. Results of these experiments are compared with results of feeding similar diets to rats and monkeys.     

Inhibition of Key Enzymes Linked to Obesity by Preparations From Mediterranean Dietary Plants: Effects on α-Amylase and Pancreatic Lipase Activities

One of the most important strategy in the treatment of obesity includes the development of nutrient digestion and absorption inhibitors. Inhibition of digestive enzymes is one of the most widely studied mechanisms used to determine the potential efficacy of natural products as hypolipidemic and hypoglycaemic agents. In vitro studies here reported were performed to evaluate the inhibitory activity of five species (as hydroalcoholic extracts) of edible plants from Calabria region (Italy) on amylase and lipase by monitoring the hydrolysis of p-NPC and the hydrolysis of glycoside bonds in digestible carbohydrate foods. The formulation obtained from Clematis vitalba L. exhibited the strongest inhibitory effect on pancreatic lipase (IC₅₀?=?0.99 mg/ml) and on α-amylase (IC₅₀?=?31.52 μg/ml). In order to explore metabolome production HPTLC analysis of the extracts was performed, revealing the predominance of (±)-catechin, caffeic acid and chlorogenic acid in C. vitalba formulation at concentration of 23.18?±?3.14, 13.63?±?0.65 and 18.88?±?0.76 mg/g, respectively. GC/MS analysis was used to identify fatty acids and terpene composition.     

Signal Transducers and Activators of Transcription (STAT) Regulatory Networks in Marine Organisms: From Physiological Observations towards Marine Drug Discovery

Part of our ocean’s richness comes from its extensive history of supporting life, resulting in a highly diverse ecological system. To date, over 250,000 species of marine organisms have been identified, but it is speculated that the actual number of marine species exceeds one million, including several hundreds of millions of species of marine microorganisms. Past studies suggest that approximately 70% of all deep-sea microorganisms, gorgonians, and sea sponges produce secondary metabolites with anti-cancer activities. Recently, novel FDA-approved drugs derived from marine sponges have been shown to reduce metastatic breast cancer, malignant lymphoma, and Hodgkin’s disease. Despite the fact that many marine natural products have been shown to possess a good inhibition potential against most of the cancer-related cell signaling pathways, only a few marine natural products have been shown to target JAK/STAT signaling. In the present paper, we describe the JAK/STAT signaling pathways found in marine organisms, before elaborating on the recent advances in the field of STAT inhibition by marine natural products and the potential application in anti-cancer drug discovery.     

Antitumor Compounds from Marine Actinomycetes

Chemotherapy is one of the main treatments used to combat cancer. A great number of antitumor compounds are natural products or their derivatives, mainly produced by microorganisms. In particular, actinomycetes are the producers of a large number of natural products with different biological activities, including antitumor properties. These antitumor compounds belong to several structural classes such as anthracyclines, enediynes, indolocarbazoles, isoprenoides, macrolides, non-ribosomal peptides and others, and they exert antitumor activity by inducing apoptosis through DNA cleavage mediated by topoisomerase I or II inhibition, mitochondria permeabilization, inhibition of key enzymes involved in signal transduction like proteases, or cellular metabolism and in some cases by inhibiting tumor-induced angiogenesis. Marine organisms have attracted special attention in the last years for their ability to produce interesting pharmacological lead compounds.