共查询到16条相似文献，搜索用时 125 毫秒
1.
利用酶动力学方法测定了50％乙醇红茶萃取物和其主要活性成分茶黄素对存在于动物中的I型脂肪酸合酶的酮酰还原催化中心（KR）和存在于细菌中的II型脂肪酸合酶的酮酰还原酶（FabG）的抑制能力和抑制特征。这两个抑制剂对KR和FabG均有强的可逆抑制和不可逆抑制能力，是KR和FabG的底物NADPH的竞争性抑制剂，并且NADPH可以显著降低它们不可逆失活KR和FabG的速率，表明这两个抑制剂可能作用于两种酮酰还原酶的NADPH结合位点。两个抑制剂对KR和FabG的抑制特征基本一致，表明两种不同进化程度的酮酰还原酶的活性部位很相似。序列同源性分析表明它们有一段同源性很高的序列，可能与活性部位组成有关。因此，通过对FabG的研究能够了解KR活性部位的空间结构。由于抑制能力强和来源丰富，这二个抑制剂具有较高的应用潜力。 相似文献
2.
首乌藤提取物对动物脂肪酸合酶的抑制及其减肥抑食作用 总被引：1，自引：0，他引：1
最新报道脂肪酸合酶（FAS）是治疗肥胖症的潜在靶部位。实验测定表明，中药首乌藤的提取物对FAS具有很强的抑制作用，半抑制浓度为0.61±0.024g/ml。同时测定，该提取物对FAS中的酮酰还原反应有强抑制，半抑制浓度为2.14±0.12g/ml，说明FAS中的酮酰还原酶是该提取物的作用部位之一。抑制动力学分析表明，首乌藤提取物对FAS的抑制和底物乙酰辅酶A、丙二酸单酰辅酶A之间皆呈非竞争性关系；和NADPH之间在低抑制剂浓度下的表现近似反竞争性，在高抑制剂浓度下接近竞争性的关系。推测首乌藤中可能有多种FAS抑制剂。用首乌藤提取物口服饲喂大鼠和小鼠，可明显减低实验动物的摄食量和体重；测定实验组大鼠肝脏的FAS活性，明显低于对照组。实验结果对于研究FAS抑制剂和抑制机制以及在防治肥胖症的应用上可能具有重要的价值。 相似文献
3.
草莓提取物对脂肪酸合酶及脂肪细胞的抑制作用 总被引：1，自引：0，他引：1
脂肪酸合酶(FAS)是治疗肥胖症的潜在靶点.实验测定表明,草莓果肉渣及草莓叶的乙醇提取物再经乙酸乙酯萃取的有效组分对FAS具有强抑制作用,且分别对FAS的底物丙二酸单酰辅酶A、乙酰辅酶A呈非竞争性和竞争性抑制.经HPLC-MS分析,槲皮素和鞣花酸可能是草莓有效组分中起主要作用的物质.草莓叶及果肉渣乙酸乙酯提取组分均可有效抑制3T3-L1前脂肪细胞中脂滴积累,且呈剂量依赖性.实验结果对于研究草莓在防治肥胖症的应用上可能具有重要价值. 相似文献
4.
最新报道脂肪酸舍酶（EC．2．3．1．85,Fattyacidsynthase,FAS）是治疗癌症和肥胖的双重靶部位。本文对24种抗肿瘤中药进行抑制FAS活性研究。实验结果表明,这24种中药中有17种具有抑制FAS生物活性（抑制率I〉40％）,其中9种中药抑制FAS活性较高（抑制率I〉70哟,为寻找无毒、低成本的FAS抑制剂提供依据。 相似文献
5.
本文推导了一个新的鸡肝脂肪酸合成酶的作用动力学公式。该公式不仅可以解释乙酰辅酶 A 和丙二酰辅酶 A 的竞争性双底物抑制,而且反映了新的还原性辅酶Ⅱ的底物抑制,以及辅酶 A 的辅助底物作用,从而弥补了以前的脂肪酸合成酶作用动力学公式的不足。该公式符合实验结果,并可用它来计算一些有关动力学常数如下:K_(mA)=12μM,K_(mM)=17μM,K_(mN)=31μM。 相似文献
6.
中药寒热相关药性和抑制脂肪酸合酶能力关系的探索 总被引：1，自引：0，他引：1
测定了药典中106味温热性中药和119味寒凉性中药对脂肪酸合酶的抑制水平,发现温热药中对该酶强抑制的频数高于寒凉药约38％.进一步分析发现,温热药中的温里和散内寒药中强抑制药的频数大幅提高,而寒凉药中的清热泻火、明目、清虚热药中强抑制药的频数则进一步降低,差异均具有显著性.综合以上结果提出,直接影响能量代谢系统、造成能量代谢率变化是形成中药的寒热药性的因素之一. 相似文献
7.
8.
9.
<正>引言众所周知,茶叶是中国自古以来最重要的饮料,而它也走出中国,走向世界,成为世界三大饮料之一。改革开放以来,我国在茶业上的飞速发展,无论产量和种植面积都是全球之首。最近几年来,我国的茶叶出口量均逐年上升,出口金额再次创下新高。根据茶叶及其生产工艺不同,可分为绿茶、黄茶、白茶、红茶、乌龙茶,等等,其中在中国最受欢迎的一种是绿茶,无论花色还是品种之多均是无可争议的世界第一。绿茶中富含茶多酚、蛋白质、维生素、氨基酸等大量有机化学成分,并含有多种无机矿物元素,具有延缓衰老、强身健体的多重功效。 相似文献
10.
抑癌基因PTEN是双特异性磷酸脂酶．在多种恶性肿瘤中发生突变或缺失,导致其抑癌功能减弱或丧失．在多种恶性肿瘤的发生、发展中起重要作用．PTEN通过复杂的信号转导网络（P13K／AKT．FAK／MAPK．PTEN／P53／MDM2）调控细胞周期．促进细胞凋亡．抑制肿瘤的血管形成和侵袭转移等．对PTEN基因的深入研究将为恶性肿瘤的早期诊断、临床监测、基因靶向治疗．预后评估、新药研发和一级预防提供科学的理论依据。 相似文献
11.
BackgroundInferior Tieguanyin oolong tea leaves were treated with tannase. The content and bioactivity of catechins in extracts from the treated tea leaves were investigated to assess the improvement in the quality of inferior Tieguanyin oolong tea.ResultsAnalysis showed that after treatment, the esterified catechin content decreased by 23.5%, whereas non-galloylated catechin and gallic acid contents increased by 15.3% and 182%, respectively. The extracts from tannase-treated tea leaves showed reduced ability to bind to BSA and decreased tea cream levels. The extracts also exhibited increased antioxidant ability to scavenge OH and DPPH radicals, increased ferric reducing power, and decreased inhibitory effects on pancreatic α-amylase and lipase activities.ConclusionsThese results suggested that tannase treatment could improve the quality of inferior Tieguanyin oolong tea leaves. 相似文献
12.
13.
Ramesh Chander A. K. Khanna Kanwal Raj A. K. Rastogi 《Indian journal of clinical biochemistry : IJCB》2005,20(1):153-159
Indian black tea; CTC leaf and dust, produced by Tata Tea Limited, Kolkata, (India) was studiedin vitro as potential scavenger of oxygen free radicals. Super oxide anions were generated in a system containing xanthine—xanthine
oxidase (enzymic system) and by NADH- phenozine methosulphate (non enzymic system). Anions were assayed in terms of uric acid
formation and reduction of nitroblue tetrazolium salt, which were shown to be suppressed by tea extracts. Extracts from both
leaf and dust also inhibted the formation of hydroxyl radicalsin vitro in the enzymic system comprising hypoxanthine—Cu+2—sodium ascorbate and xanthine oxidase and in non enzymic system of deoxyribose—Cu+2—sodium ascorbate and H2O2 as well as the Cu+2 induced lipid peroxidation in human low density lipoprotein. Feeding with black tea in normal rats for sixty days increased
their antioxidant activity and their liver microsomes were shown to be protected against peroxidation of lipids as stimulated
by metal ions with enzymic or non enzymic reactants. Furthermore feeding with tea extracts in normal as well as triton WR—1339
induced hyperlipidemic rats caused decrease in their plasma levels of total cholesterol, phospholipids and triglycerides.
The antioxidant and lipid lowering activities of both extracts from CTC leaf and dust tea was comparable and may be due to
the presence of natural products like catechin and others. 相似文献
14.
BackgroundChia seeds are gaining increasing interest among food producers and consumers because of their prohealth properties.ResultsThe aim of this work was to evaluate the potential of chia seeds to act as acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitors. The highest inhibitory activity against AChE and BChE was observed for colored seed ethanol extracts. A positive correlation was found between the presence of quercetin and isoquercetin as well as protocatechuic, hydroxybenzoic, and coumaric acids and the activity of extracts as AChE and BChE inhibitors. It has also been shown that grain fragmentation affects the increase in the activity of seeds against cholinesterases (ChE). Furthermore, seeds have been shown to be a source of substances that inhibit microbial growth.ConclusionsIt was found that the chia seed extracts are rich in polyphenols and inhibit the activity of ChEs; therefore, their use can be considered in further research in the field of treatment and prevention of neurodegenerative diseases.How to cite: Kobus-Cisowska J, Szymanowska D, Maciejewska P, et al. In vitro screening for acetylcholinesterase and butyrylcholinoesterase inhibition and antimicrobial activity of chia seeds (Salvia hispanica). Electron J Biotechnol 2019;37. https://doi.org/10.1016/j.ejbt.2018.10.002 相似文献
15.
绿茶多酚类化合物抗肿瘤作用研究 总被引：2，自引：0，他引：2
对荷瘤小鼠喂服一定剂量(每千克体重喂40mg、80mg和120mg)的绿茶多酚后,测定其对移植性肿瘤细胞的抑制作用,结果显示:对EAC重量的抑制率分别为65.3％、51.0％和48.7％;对S180的抑制率为66.3％、68.5％和59.8％;对EAC细胞增殖数抑制率为81.4％、77.0％和50.5％.同时测得三个试验组EAC鼠的胸腺细胞增加率为248.2％、69.6％和44.6％;脾细胞增殖率为13.5％、61.5％和22.9％;对S180鼠的胸腺细胞增加率为200.7％、73.9％和138.0％;脾细胞增加率为34.4％、31.1％和20.0％.实验结果表明:茶多酚抗肿瘤作用可能是通过增强机体免疫力来抑制体内肿瘤细胞的生长. 相似文献
16.
四川生态茶园的建设与我国其它地区有其相似性和特殊性。本文从四川茶区的生态气候和植被区系特点出发，从理论和实践角度探讨了建设四川生态茶园的可行性和不同适宜类型。以及适合茶园间作的林、果、药、绿肥等植物的种类和布置方法。 相似文献