伏康树中单萜吲哚类生物碱及其NMR波谱特征

伏康树中主要化学成分为生物碱类化合物。自1956年首次从非洲马铃果中分离得到老刺木灵至今,已从该植物中分离出多种吲哚类生物碱。该类生物碱在天然产物中生物活性优异而广泛,尤其是近年来研究发现其在抗肿瘤方面表现良好,因此对该类化合物进行研究具有重要意义。本文查阅国内外研究文献,将伏康树中分离得到的生物碱及NMR波谱特征进行归纳、总结。迄今已从伏康树中分离鉴定了69个生物碱,均为单萜吲哚类生物碱,其中单萜吲哚生物碱46个,双聚单萜吲哚生物碱23个。这些生物碱结构复杂,骨架类型丰富,但在结构上有一定规律,根据单萜部分结构变化对其结构进行分类,同时对各类型单萜吲哚类生物碱波谱规律进行总结,对进一步鉴定该类化合物结构以及进行波谱数据的归属都起着重要的作用。     

萝芙木Srictosidine合成酶cDNA克隆:核苷酸序列确定及在大肠杆菌中的表达

1968年人们发现生物碱糖苷,strictosidine,是类单萜吲哚生物碱生物合成的前体。然而对于类单萜吲哚生物碱生物合成途径第一个中间产物的strictosidine立体化学,直到发现和鉴定色胺和双联色木鳖酸立体专一性缩合反应的酶后才被弄清楚。 Strictosidine是1800种以上吲哚生物碱的前体,在这些吲哚生物碱中有些有很高的商业价值。Strictosidine已被证实带有3α(S)一构型。催化strictosidine形成的酶被命名为strictosidine合成酶。一个方便的试     

法国天然产物化学研究近况

本文简述了近年来法国在天然产物化学领域的研究近况。文章以 P.Potier,H.P.Husson等领导的法国几个主要的天然药物化学实验室开展的研究为主,介绍了这几年法国在天然产物分离,结构鉴定和合成方面的研究进展。综述表明,近年来法国天然药化重点研究对象是紫杉醇及其衍生物和生物活性的吲噪生物碱。     

吲哚生物碱生物合成研究进展

生物碱种类繁多,吲哚类生物碱是迄今为止发现最多的一类,是许多药用植物的药效成分,具有多样的生物活性。随着代谢组学技术的发展,研究药效物质的生物合成途径对阐明植物体内代谢的分子机制以及代谢调控机理具有重要意义,对进一步研究提高药效物质的生物合成产量具有指导意义。本文按照吲哚生物碱结构进行分类,对数种吲哚生物碱的生物合成途径研究进展进行综述,以期为吲哚生物碱的生物合成机制的进一步研究奠定基础,为其他吲哚生物碱类成分的生物合成研究提供参考依据。     

抗肿瘤药用植物有效成分研究概况

从药用植物抗肿瘤活性成分的化学结构、药理活性及其构效关系等方面综述了近几年来国内外有关喹啉类生物碱，吲哚类生物碱，芪类化合物，二萜类化合物，五环三萜类化合物，黄酮类化合物，内酯类化合物，醌类化合物，多糖类化合物，蛋白质类化合物以及一些具有抗癌活性的多炔类化合物等中草药活性成分在抗肿瘤方面的研究进展。总结并探讨了当今抗肿瘤天然产物研究发展的新方向。     

钩藤中吲哚类生物碱化学成分及药理活性研究进展

钩藤,原名钓藤,入药历史悠久,主要用来治疗风热头痛、头晕目眩、小儿惊厥、高血压等症状.近年来,大量药理实验证明,钩藤中的主要活性成分是吲哚类生物碱.就钩藤中的吲哚类生物碱的化学成分及其药理活性进行系统性综述,为进一步开发利用中药钩藤提供理论依据.     

对天然产物抑制HIV-1逆转录酶的评价

对HIV-1逆转录酶的抑制是目前被认为是预防爱滋病有益的新进展。天然产物已广泛用作HIV-1逆转录酶(HIV-1RT)的抑制剂。作者开发的在病毒粒子中检测HIV-1的方法,可作为天然产物对HIV-1RT的抑制作用的筛选方法,作者筛选了156种纯天然产物。鸟成髓细咆血症病毒逆转录酶的抑制剂苯并菲啶生物碱氯化崖椒宁(fagarnoninechloride)和氯化两面针碱(nitidine chloride)对HIV-1RT具有显著活性,因此以这两个化合物作为筛选时的阳性对照。作者发现非洲汉防己碱(columbamine)和另一些原小檗碱异奎宁碱(如o-methyl psychotrine sulfate和iri-doid fulvo plumierin)具有抑制作用。而一些吲哚类等其它类型的生物碱却无活性。作者筛     

天然药物吴茱萸生物碱研究进展

吴茱萸碱及吴茱萸次碱是色胺吲哚类生物碱，主要存在于吴茱萸中。吴茱萸碱及吴茱萸次碱具有护心降低血压，调脂、镇痛及抗炎等作用。而最近研究表明，吴茱萸生物碱对皮肤病也具有明显的临床疗效。     

天然药物吴茱萸生物碱研究进展△

吴茱萸碱及吴茱萸次碱是色胺吲哚类生物碱，主要存在于吴茱萸中。吴茱萸碱及吴茱萸次碱具有护心降低血压，调脂、镇痛及抗炎等作用。而最近研究表明，吴茱萸生物碱对皮肤病也具有明显的临床疗效。     

长春花萜类吲哚生物碱生物合成与调控研究

长春花含有多种具有重要药理活性的萜类吲哚生物碱(TIA)。TIA的生物合成与调控及其合成生物学研究受到广泛关注。3α(S)-异胡豆苷是TIA生物合成的重要节点,由裂环马钱子苷和色胺缩合而成。前者通过环烯醚萜途径生成;后者通过吲哚途径生成。由3α(S)-异胡豆苷分别经过多步酶促反应生成文多灵和长春质碱,然后两者缩合生成α-3,4-脱水长春碱,进而生成长春碱和长春新碱。AP2/ERF和WRKY等多种转录因子参与了TIA合成的调控。长春花TIA生物合成途径的逐步解析为其合成生物学研究奠定了基础。目前已在酿酒酵母实现了3α(S)-异胡豆苷和文多灵等的异源合成。长春花TIA生物合成与调控的研究将为TIA类药物的生产和研发提供支撑。     

作用于微管的天然产物

微管在有丝分裂中扮演着重要的角色,微管靶点药物是抗肿瘤药物的重要组成部分。很多天然产物能作用于微管的不同部位,其中包括紫杉醇类和长春花碱类。根据这些天然产物对微管蛋白聚合所起的促进作用或抑制作用,将其划分成两类,着重讨论它们的来源、作用机制和生物活性。     

Countercurrent separation of natural products

An assessment of the technology and method development in countercurrent chromatography (CCC) and centrifugal partition chromatography (CPC), collectively referred to as countercurrent separation (CS), is provided. More than six decades of CS theory and applications are critically reviewed and developed into a practical guide to CS for natural products research. The necessary theoretical foundation is given for better use of CS in the separation of biological molecules of any size, small to large, and from any matrix, simple to complex. The three operational fundamentals of CS--instrumentation, biphasic solvent systems, and theory--are covered in a prismatic fashion. The goal of this review is to provide the necessary background and references for an up-to-date perspective of CS and to point out its potential for the natural products scientist for applications in natural products chemistry, metabolome, and proteome research involving organisms from terrestrial and marine sources.     

海洋天然产物研究概述

近年来海洋天然产物越来越引起科学家们的注意,在浩瀚的海洋中存在着大量令人激动、活性独特、结构新颖的次生代谢产物。海洋天然产物已成为发现重要先导药物和新的生物作用机制的主要源泉。对目前海洋天然产物研究概况进行综述,其中重点介绍大环内酯类和聚醚类等化合物。     

A review of antimycobacterial natural products

Tuberculosis is a chronic infectious disease caused by several species of mycobacteria. Due to multi-drug resistant strains of mycobacteria and to a high prevalence of tuberculosis in patients who have acquired human immunodeficiency syndrome (AIDS), the number of patients infected with the disease is increasing worldwide. Thus there is an urgent need for new effective antimycobacterial agents to replace those currently in use. In this instance, the plant kingdom is undoubtedly a valuable source for new anti-tuberculosis agents. The present review article reports the findings from an extensive literature search of all plants that have been assessed for antimycobacterial/antitubercular activity over the past 20-30 years. An attempt has been made to summarize the information in order to highlight those promising plant species which are worthy of further investigation as leads for drug development. Over 350 plant species from a wide range of families and origins, containing various chemical classes of compounds, have been screened for such activity. A review of the relevant in vitro assays using different species of pathogenic and non-pathogenic mycobacteria is also included.     

Biosynthesis of unusual aminocyclitol-containing natural products

The aminocyclitol family of natural products is a class of sugar-derived microbial secondary metabolites that demonstrate significant biological activities. Within this class of natural products are the C7N-aminocyclitol-containing compounds, which were originally associated with potent sugar-hydrolase inhibition. However, recent discoveries indicate a broader array of chemical structures and biological activities of this class of compounds. Using both conventional feeding experiments and contemporary molecular genetic approaches, some progress has been made in understanding the biosynthesis of this class of natural products. Results of in silico investigation also suggest a wide distribution of this class of natural products or closely related compounds across different classes of microorganisms, including cyanobacteria and fungi. This review describes our recent progress in the biosynthetic studies of a number of C7N-aminocyclitol-containing compounds and the potential use of bioinformatic approaches to search for novel aminocyclitol-containing natural products.     

天然药物化学史话:天然产物的生物合成

天然产物因其独特的化学结构,往往具有特定靶点、专一性结合的能力而表现出良好的生物活性,因而一直是生物活性前体化合物和新药发现的重要源泉。植物体通过一次代谢过程和二次代谢过程,仅用简单的原料二氧化碳和水,在酶的作用下就合成了结构千差万别的各类型天然产物。其中一些结构特异、生物活性较强的化合物也成了有机合成化学家们竞相研究的热点。阐明天然产物的生物合成途径,不仅有助于天然产物人工合成的设计和结构推导;同时,生物合成的原理、反应类型及反应机制也为有机合成研究领域提供了灵感,开拓了思路,催生了许多新颖的合成方法;以天然产物化学和分子生物学的发展和融合为基础的化学生物学和合成生物学的诞生将催生下一次生物技术革命。     

Antimutagenic agents from natural products.

Certain secondary metabolites found in terrestrial and marine plants and organisms have evinced the capability for inhibiting the mutagenicity toward Salmonella typhimurium of a number of mutagens. These include 2-aminoanthracene (2AN), ethylmethanesulfonate (EMS), and benzo-[a]pyrene(B[alpha]P). The sensitivity of the antimutagenicity assay is such that crude extracts can be evaluated and purification of extracts readily followed. Major classes of antimutagenic compounds that have been isolated include flavonoids, coumarins, and cymopols.     

Dereplication of microbial natural products by LC-DAD-TOFMS

Dereplication, the rapid identification of known compounds present in a mixture, is crucial to the fast discovery of novel natural products. Determining the elemental composition of compounds in mixtures and tentatively identifying natural products using MS/MS and UV/vis spectra is becoming easier with advances in analytical equipment and better compound databases. Here we demonstrate the use of LC-UV/vis-MS-based dereplication using data from UV/vis diode array detection and ESI+/ESI- time-of-flight MS for assignment of 719 microbial natural product and mycotoxin reference standards. ESI+ was the most versatile ionization method, detecting 93% of the compounds, although with 12% ionizing poorly. Using ESI+ alone, 56.1% of the compounds could be unambiguously assigned based on characteristic patterns of multiple adduct ions. Using ESI-, 36.4% of the compounds could have their molecular mass assigned unambiguously using multiple adduct ions, while a further 41% of the compounds were detected only as [M - H]-. The most reliable interpretations of conflicting ESI+ and ESI- data on a chromatographic peak were from the ionization polarity with the most intense ionization. Poor ionization was most common with small molecules (<200 Da). In ESI-, these were often polar and basic, while in ESI+ they were small aromatic acids or anthraquinones. No single ion-source settings could be applied over a m/z 60-2000 range. However, continuous switching among three settings (e.g., for 0.5 s each) during the chromatographic run allowed MS of both small labile molecules and large peptides, and pseudo MS/MS data on labile molecules since the settings for large molecules often induce fragmentation into small molecules.     

Potential of natural products as insect antifeedants

Insect antifeedants are the substances that play a significant role in host plant selection by phytophagous insects. Extensive work has been done on natural antifeedants and a large number of these compounds have been identified belonging to different classes during the past decade. The present article deals with various chemical and biological aspects of insect antifeedants and with their possible role in insect pest management.