共查询到20条相似文献,搜索用时 31 毫秒
1.
从中国广西药用植物苍白秤钩风(Diploclisia glaucescens)藤茎的95%乙醇提取物中分离得到5个脱皮甾酮类化合物(1-5)。通过NMR、MS以及化学沟通等方法分别将其结构鉴定为paristerone C-20,22-monoacetonide(1),paristerone(2),eodysterone(3),makisterone C(4)和capisterone(5)。化合物1为首次从自然界分得的天然产物,2,4,5亦为首次从该植物中分得。 相似文献
2.
Brahmachari G Mondal S Gangopadhyay A Gorai D Mukhopadhyay B Saha S Brahmachari AK 《化学与生物多样性》2004,1(11):1627-1651
A compilation of the constituents isolated from Swertia species covering the literature up to December 2003 is presented. The botanical classification and ethno-pharmacology of Swertia plants, as well as the biological activities and pharmacological applications of both distinct phytochemicals and medicinally active plant materials (formulations, extracts, etc.) are discussed in detail. 相似文献
3.
Purification and characterization of the acyl carrier protein of the Streptomyces glaucescens tetracenomycin C polyketide synthase.
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B Shen R G Summers H Gramajo M J Bibb C R Hutchinson 《Journal of bacteriology》1992,174(11):3818-3821
The acyl carrier protein (ACP) of the tetracenomycin C polyketide synthase, encoded by the tcmM gene, has been expressed in both Streptomyces glaucescens and Escherichia coli and purified to homogeneity. Expression of the tcmM gene in E. coli results mainly in the TcmM apo-ACP, whereas expression in S. glaucescens yields solely the holo-ACP. The purified holo-TcmM is active in a malonyl coenzyme A:ACP transacylase assay and is labeled by radioactive beta-alanine, confirming that it carries a 4'-phosphopantetheine prosthetic group. 相似文献
4.
本文综述了近十年来唐松草属植物化学成分的结构、来源及其药理活性的研究进展。 相似文献
5.
苍白秤钩风中木脂素类化学成分的研究 总被引:2,自引:0,他引:2
从中药苍白秤钩风Diploclisiaglaucescens的藤茎中首次分离得到三个木质素类化合物 ,根据理化性质 ,波谱分析 ,化学方法以及X衍射实验 ,分别将其结构确定为左旋丁香脂素 (1)、(7S ,8R ,8’R) 5 ,5’ 2甲氧基落叶松树脂醇 (2 )和 (7S ,8R) 二聚松柏醇 (3)。 相似文献
6.
大瘤足蕨和镰羽瘤足蕨的化学成分研究 总被引:1,自引:0,他引:1
对瘤足蕨属中的大瘤足蕨和镰羽瘤足蕨进行化学成分研究,从这两种植物中分离并鉴定了9个化合物,分别是:大波斯菊苷(1)、异山奈甲黄素(2)、astragalin(3)、3β,27-dihydroxylup-12-ene(4)、hydroxyhopanone(5)、plagiogyrin a(6)、androsin(7)、β-谷甾醇(8)、β-胡萝卜苷(9).所有化合物均为首次从这两种植物中分离得到,其中化合物1、4、7、9为这两种植物的共有成分. 相似文献
7.
崖豆藤属植物中异黄酮类化学成分及其药理活性的研究进展 总被引:5,自引:0,他引:5
本文对豆科崖豆藤属植物中的异黄酮类化学成分及此类成分药理活性的国内外研究进行综述。从崖豆藤属植物中分离得到异黄酮类化合物159个,包括异黄酮及其苷类、鱼藤酮类、异黄烷类、紫檀烷类、二氢异黄酮类,它们具有抗肿瘤、抗炎、抗雌激素等作用。 相似文献
8.
通过对短葶飞蓬(Erigeron breviscapus)不同产地的44个种群植株的总黄酮、灯盏乙素和总咖啡酸酯含量与产地土壤全氮(N)和速效N含量的相关分析, 探讨了产地间土壤N含量变化在药用植物短葶飞蓬植株次生代谢有效成分含量变化中的作用机制。结果显示: 土壤全N含量与种群植株中总黄酮含量呈显著的负相关(r=-0.391, p<0.01), 而与总咖啡酸酯和灯盏乙素关系不显著; 土壤速效N含量与种群植株中总黄酮(r=-0.528, p<0.01)、灯盏乙素(r=-0.490, p<0.01)和总咖啡酸酯含量(r=-0.471, p<0.01)都表现出更高的极显著负相关关系。全部44个种群中, 有效N供应量变化只能解释次生代谢产物含量的17%~30%的变化。非石灰土壤与石灰土壤的种群分开进行线性回归, 可解释总黄酮含量产地间约80%的变化, 以及灯盏乙素和总咖啡酸酯含量约60%的变化。植株总黄酮、灯盏乙素和总咖啡酸酯含量都与植株含N量存在显著的负相关关系。研究表明: 土壤丰富的有效N供应不利于黄酮和咖啡酸酯的合成积累, 与“碳素/营养平衡假说”的预测一致; 土壤有效N对植物次生代谢产物的影响会受到植物体内外因素的影响。不同产地的短葶飞蓬的黄酮等酚类次生代谢产物含量的差异, 可能是产地间不同的土壤N供应量和其他生态因子及遗传变异共同作用的结果。 相似文献
9.
铁线莲属植物的化学成分研究进展 总被引:1,自引:0,他引:1
多年来,铁线莲属许多植物的根作为传统中药“威灵仙”入药。近几十年来,从该属植物中分离得到多种化合物,如三萜皂苷、黄酮、生物碱、原白头翁素等成分。文章重点介绍了铁线莲属植物的化学成分研究进展,有助于对该属植物做进一步的开发。 相似文献
10.
As part of an ongoing study of traditional Chinese medicinal plants, the root tissue of Salvia miltiorrhiza was further investigated for its chemical constituents. Five naturally occurring products along with 13 known constituents were isolated from an ethyl acetate-soluble portion of its ethanol extract. Their structures were elucidated by means of spectroscopic methods. Some selected compounds were also evaluated for biological activity. 相似文献
11.
Four kinds of crystal constituents were isolated from the roots of Ostericum citriodorum (Hance) Shah et Yuan. They were identified by IR, NMR and MS, as (E)-isodillapiol, β-sitosterol, isodillapiolglycol and the other one crystal constituent will study continuously. The (E)-isodillapiol is first isolated from the plants and the isodillapiolglycol is a new compound. 相似文献
12.
川产八角莲中鬼臼毒素的分离鉴定及含量测定 总被引:5,自引:1,他引:4
为了寻找和开发抗癌药的半合成原料鬼臼毒素,我们对川产八角莲的化学成分进行了研究。从川八角莲[Dysosma veitchii(Hemsl et wils)Fu.]的根茎中分离得到一种单体成分,经薄层对照,熔点,UV,IR,MS和H’—NMR测定,证明为鬼臼毒素(Podophyllo-toxin)。同时,作者采用薄层层析—紫外分光光度法,对川八角莲和小八角莲[D.difformis(Hernsl et wils)T.H·wang ]中的鬼臼毒素进行了含量测定,分别为0.057%和0.15%。为进一步开发利用鬼臼类植物提供了科学依据。 相似文献
13.
14.
本文综述了迄今为止从石蒜科龙舌兰属植物中分离得到的化学成分及其分布,并介绍了。一些植物和化合物的药理作用。 相似文献
15.
Many doubts still persist even today when it comes to selection of the solvents for extracting the active constituents from
various Indian medicinal plants. This study was aimed at assessing and establishing the best solvent for extracting the active
constituents from 10 plant extracts. Thin layer chromatography (TLC) was used to separate and establish the active constituents
present in each of the medicinal plants. Active constituents from each plant were extracted by using three different solvent
systems namely diethyl ether, chloroform and hexane and were tested against three species of gram negative and three species
of gram positive bacteria (Escherichia coli, Pseudomonas aureginosa, Streptococcus pneumoniae, Aeromonas hydrophila, Staphylococcus aereus, Bacillus cereus) by means of agar well diffusion assay. Studies on the antioxidant activity studies were also carried out for these plant
extracts by using Diphenylpicryl-hydrazyl (DPPH) method. For the antimicrobial activity, the study revealed that among the
selected plants, Azadiracta indica, Pongamia pinnata, Aloe barbadensis had the maximum antibacterial activity. Among the extraction procedures diethyl ether was found to be the best solvent that
could be used for the extraction procedure. On the antioxidant activity part, Coleus amboinicus and Calotropis procera were found to have high antioxidant activity of 91.64% and 88.72% respectively and the further results are reported and discussed. 相似文献
16.
17.
Identification of two histidines as copper ligands in Streptomyces glaucescens tyrosinase 总被引:2,自引:0,他引:2
The physiochemical properties of wild type and two mutants of Streptomyces glaucescens tyrosinase are reported. The native enzyme contains two coppers at the active site which are EPR nondetectable. The two coppers react stoichiometrically with one hydrogen peroxide molecule giving rise to oxytyrosinase. Its optical features are similar to those reported earlier for a molluscan hemocyanin. The two mutants in which histidine-62 and -189 were changed to asparagine by site-directed mutagenesis have lost their enzymatic activity and their ability to bind oxygen and contain only one copper ion which is fully EPR detectable. The EPR parameters indicate that the remaining copper is in a tetragonally distorted ligand environment. These data are in agreement with His-62 and His-189 serving as copper ligands in S. glaucescens tyrosinase. 相似文献
18.
Köhler I Jenett-Siems K Kraft C Siems K Abbiw D Bienzle U Eich E 《Zeitschrift für Naturforschung. C, Journal of biosciences》2002,57(11-12):1022-1027
Different extracts from 11 West African plants traditionally used against malaria in Ghana were tested against both the chloroquine-sensitive strain PoW and the chloroquine-resistant clone Dd2 of Plasmodium falciparum. Due to the promising in vitro activity of the lipophilic extract [IC50: 10.5 microg/ml (PoW); 13.1 microg/ml (Dd2)], Microglossa pyrifolia (Lam.) Kuntze (Asteraceae) was chosen for further phytochemical investigation. From active fractions 13 compounds were isolated; their structures were established on the basis of spectroscopic methods. 1-Acetyl-6E-geranylgeraniol-19-oic acid and sinapyl diangelate represent new natural compounds. The two diterpenes E-phytol [IC50: 8.5 microM (PoW); 11.5 microM (Dd2)], and 6E-geranylgeraniol-19-oic acid [IC50: 12.9 microM (PoW); 15.6 microM (Dd2)] proved to be the most active constituents in our test system. 相似文献
19.
近几十年来,从木槿属植物中分离得到多种化合物,如木脂素、黄酮、萜类、mansonones类等化合物类型。文章重点介绍了木槿属及该属植物海滨木槿的研究进展,有助于对该属植物海滨木槿的进一步开发与研究。 相似文献
20.
Renu Bhardwaj Sukhbir Kaur Pramodh Kumar Nagar Hardesh Kumar Arora 《Plant Growth Regulation》2007,53(1):1-5
Brassinosteroids play an important role in growth and development of plants. They have been reported universally in all the
plants. The present study deals with the presence of these compounds in immature tea seeds. Five brassinosteroids, i.e. 6-deoxo-28-norcathasterone,
6-deoxo-28-norteasterone, 3-dehydro-6-deoxo-28-norteasterone, 6-deoxo-28-nortyphasterol and 6-deoxo-28-norcastasterone have
been isolated and identified by GC–MS. The identified brassinosteroids and their derivatives are active constituents of late
C-6 oxidation pathway, thereby suggesting the biosynthesis of brassinosteroids in tea seeds by late C-6 oxidation pathway. 相似文献