两种中药虎皮楠和交让木化学成分的研究

交让木(Daphniphyllum macropodum)和虎皮楠(Daphniphyllum angustifolium)属于虎皮楠科虎皮楠属,为小乔木.近年来,从虎皮楠属植物中分离得到一系列结构非常复杂的、独特的、生物活性多样的聚环生物碱[1,2],我们从交让木(D.macropodum)中分得7个此类生物碱,根据NMR和MS数据鉴定了3个化合物的结构,其中1个为新化合物.另外4个化合物的结构正在鉴定中.经文献查阅发现对该属植物非生物碱部分的研究很少,我们从虎皮楠)(D.angustifolium)非生物碱部位分得18个化合物,并根据NMR,UV,和MS等数据鉴定了它们的结构,其中7个为新化合物.新化合物的结构如下所示:     

Daphnezomines A和B的四环核心骨架合成（英文）

在虎皮楠生物碱家族中, daphnezomine A型生物碱仅包含三位成员:daphnezomine A (1), daphnezomine B (2)以及dapholdhamineB.这些生物碱含有独特的氮杂金刚烷骨架,9个连续的手性立体中心,因此呈现出巨大的合成挑战性.报道了分子1和2的四环核心骨架的合成.关键步骤包括一个黄氏酰胺活化增环反应和一个Hutchins-Kabalka还原重排反应.     

交让木树皮中的新虎皮楠生物碱的结构研究

本文报道从虎皮楠科植物交让木的树皮中分到4个新的和7个已知的虎皮楠生物碱的结构研究。4个新生物碱分别命名为脱氧交让木碱（dehydroxymacropodumineA）(1), 4,21-脱乙酰-23-脱甲基-脱氧交让木胺（4,21-deacetyl-23-demethyl-deoxyyuzurimine） (2),7-氧杂--脱氧交让木胺（7-oxo-deoxyyuzurimine）(3),和4-乙酰氧-虎皮楠素B （4-acetoxydaphmanidinB）(4)。新化合物1-4的结构是通过仔细解析其波谱数据和与已知结构相关的化合物波谱数据比较而确定。脱氧交让木碱（dehydroxymacropodumineA）(1) 具有罕见的11元环的大环内酯结构,是从自然界中分到的第二个具有这一新颖结构特征的生物碱。     

一个新骨架二萜生物碱

从黄草乌(Aconitum vilmorinianum Kom.)根中分离得到一个新骨架二萜生物碱-黄乌定(vilmoridine, 1), 其骨架为B环对开海替定型, 还从该植物中分离到5个已知二萜生物碱。     

放线菌来源生物碱的生物合成机制

生物碱类天然产物通常具有复杂多样的化学结构和广泛的生物活性,因此备受生物学、化学、药学领域研究者的关注。微生物是仅次于植物的生物碱类天然产物重要来源,微生物尤其是放线菌产生的众多次生代谢产物中,也包括很多生物碱。对放线菌来源生物碱的骨架结构和药效基团生物合成研究,不仅能够丰富人们对天然产物结构形成原理的理解,还可以为运用合成生物学技术人工合成此类化合物提供重要的遗传元件。本文从模块化生物合成和非模块化生物合成两种方式,综述放线菌来源生物碱的生物合成基因簇、途径及其酶催化反应过程。     

环二肽合酶生物合成途径研究进展

二酮哌嗪类化合物(DKPs)的特征结构是由两个α-氨基酸通过肽键缩合而成的环二肽(CDPs),稳定的六元环骨架结构使DKPs在药物化学中成为一个重要的药效团,表现出丰富的生物活性.合成可作为药物先导物的DKPs已日益引起人们的关注,其中,开展生物合成研究是拓宽其化学结构多样性的一个有效途径.与早期阐明的非核糖体肽合成酶(NRPSs)生物合成途径不同,环二肽合酶(CDPSs)以氨酰-t RNAs(aa-t RNAs)作为底物合成环二肽,其后修饰过程发生在环二肽形成之后.目前国内外已研究的经CDPS途径合成的二酮哌嗪类化合物报道了6例.对近年来环二肽合酶(CDPSs)生物合成途径相关研究进展进行了综述.     

植物来源的糖类似物——多羟基生物碱的研究进展

多羟基生物碱是糖环上的氧原子被氮原子取代而形成的一系列衍生物, 广泛存在于植物与微生物中, 药理学研究已经证实多羟基生物碱具有高效的糖苷酶抑制活性, 糖苷酶在肠道的消化、糖蛋白加工、溶酶体代谢等方面都起着十分重要的作用, 因此多羟基生物碱具有抗糖尿病、抗癌、抗病毒、治疗溶酶体疾病等多种药理活性. 综述了这类化合物的结构、来源、分离纯化、生物活性及结构与活性的关系并对其应用前景进行了展望.     

单萜吲哚生物碱的合成生物学研究进展

单萜吲哚生物碱是一类具有重要药用价值的天然产物,但是在其宿主的生物含量很低;虽然通过有机化学的方法可以实现该类复杂结构化合物的全合成,但是难以大量快速获得,而且围绕核心骨架的进一步衍生化修饰也有一定的瓶颈.随着单萜吲哚生物碱生物合成途径的解析和合成生物学使能技术的发展,利用合成生物学策略结合化学半合成将是实现该类化合物的合成制造和通量结构衍生化的重要发展趋势.单萜吲哚生物碱基因元件的挖掘鉴定和生物合成途径的解析是进行合成生物学研究的前提条件.异胡豆苷是单萜吲哚生物碱合成的关键骨架化合物,由色胺和开环马钱子苷汇聚合成,这一过程被称为上游合成途径;以异胡豆苷为骨架形成各种单萜吲哚生物碱的过程称为下游合成途径.从这两个方面对近30年来单萜吲哚生物碱合成元件的发现和合成生物学研究进展进行了综述,为后续合成生物学的应用研究奠定基础.     

中国番荔枝科植物抗癌有效成分研究

介绍了近年来我们实验室中国番荔枝科植物抗癌有效成分研究工作。从番荔枝科5种紫玉盘属植物,5种哥纳香属植物,1种番荔枝属植物,1种囊瓣木属植物中分离得到59种新的番荔枝内酯,32种新的多氧取代环己烯,12种新的苯乙烯吡喃酮和3种新的生物碱,并通过化学和光谱方法鉴定了它们的结构。大部分化合物显示了较强的抗癌活性。并对抗癌活性成分海南哥纳香醇甲进行了全合成。     

中国大戟属植物中二萜成分的化学及生物活性

大约有80种大戟属植物广泛分布于我国,并在民间用来治疗皮肤病、水肿、结核或作为泻药和利尿剂使用.本文综述了近20年来中国产大戟属植物中14个骨架类型共150多个二萜类成分的化学研究,包括最近报道的4个具有新骨架的二萜和2个二聚体.中国产大戟属植物中的一些二萜类成分具有抗肿瘤、抗病毒、促进神经生长因子增长、皮肤刺激、致癌以及镇痛安神的活性.本文还就大戟属中二萜类成分可能的生源代谢途径提出了假设,并对该属未来的研究进行了展望.     

Daphnicyclidins A-H, novel hexa- or pentacyclic alkaloids from two species of Daphniphyllum.

Eight highly modified Daphniphyllum alkaloids with unprecedented fused hexa- or pentacyclic skeletons, daphnicyclidins A-H (1-8), have been isolated from the stems of Daphniphyllum humile and D.teijsmanni, and their structures were elucidated on the basis of spectroscopic data and chemical means. The stereochemistry was elucidated by combination of NOESY correlations, X-ray crystallographic data, and CD analyses.     

Daphnicyclidins J and K, unique polycyclic alkaloids from Daphniphyllum humile

Two Daphniphyllum alkaloids with unprecedented polycyclic skeletons, daphnicyclidins J (1) and K (2), have been isolated from the stems of Daphniphyllum humile, and the structures and relative stereochemistry were elucidated on the basis of spectroscopic data. The absolute stereochemistry of 1 was established by chemical correlation with a known-related alkaloid, daphnicyclidin D (3), through a modified Polonovski reaction.     

Macropodumines D and E, two new alkaloids with unusual skeletons from Daphniphyllum macropodum Miq

[structure: see text] Two new complex polycyclic alkaloids, macropodumines D (1) and E (2), both possessing unprecedented skeletons, along with four known related alkaloids, were isolated from the leaves and barks of Daphniphyllum macropodum Miq. The structures including the relative stereochemistry of new compounds 1 and 2 were elucidated on the basis of detailed spectroscopic data analysis.     

Angustimine and angustifolimine: two new alkaloids from Daphniphyllum angustifolium

Two new alkaloids, angustimine (1) featuring an unprecedented skeleton, and angustifolimine (2) being a rare diamino Daphniphyllum alkaloid, were isolated from Daphniphyllum angustifolium. Their structures were elucidated by extensive spectroscopic analysis. The biosynthetic origin of 1 was postulated. Cytotoxic activities of 1 and 2 were tested, and all of them were inactive.     

Characterization and identification of steroidal alkaloids in Fritillaria species using liquid chromatography coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry

Liquid chromatography coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry (LC/ESI-QTOF-MS/MS) was performed to study the fragmentation behaviors of steroidal alkaloids from Fritillaria species, the antitussive and expectorant herbs widely used in traditional Chinese medicine. We propose, herein, a strategy that combining key diagnostic fragment ions and the relative abundances and amounts of major fragment ions (the ions exceeding 10% in abundance) to distinguish different sub-classes of Fritillaria alkaloids (FAs). It was found that hydrogen rearrangement and induction effects result in ring cleavage of the basic skeletons occurred in the MS/MS process and produced characteristic fragment ions, which are useful for structural elucidation. This method was finally used to investigate the primary steroidal alkaloids in the extracts of eight major Fritillaria species. As a result, 41 steroidal alkaloids (29 cevanine type, 1 jervine type, 6 veratramine type and 5 secosolanidine type alkaloids) were selectively identified in these Fritillaria species. Twenty-six compounds were unambiguously identified by comparing with the reference compounds and 15 compounds were tentatively identified or deduced according to their MS/MS data. Logical fragmentation pathways for different types of FAs have been proposed and are useful for the identification of these types of steroidal alkaloids in natural products especially when there are no reference compounds available.     

Calyciphyllines A and B,two novel hexacyclic alkaloids from Daphniphyllum calycinum

[structure: see text] Two types of Daphniphyllum alkaloids with unprecedented fused-hexacyclic ring systems, calyciphyllines A (1) and B (2), have been isolated from the leaves of Daphniphyllum calycinum (Daphniphyllaceae), and the structures and relative stereochemistry were elucidated on the basis of spectroscopic data.     

Daphniglaucins A and B,novel polycyclic quaternary alkaloids from Daphniphyllum glaucescens

[structure: see text] Two cytotoxic quaternary Daphniphyllum alkaloids with an unprecedented fused-polycyclic skeleton containing a 1-azoniatetracyclo[5.2.2.0.(1,6)0.(4,9)]undecane ring system, daphniglaucins A (1) and B (2), have been isolated from the leaves of Daphniphyllum glaucescens. Their structures and relative stereochemistry were elucidated on the basis of spectroscopic data.     

Three New Alkaloids,Paxiphyllines C – E,from Daphniphyllum paxianum

Nine Daphniphyllum alkaloids, including three new ones, paxiphyllines C–E ( 1 – 3 , resp.), were isolated from the twigs and the leaves of Daphniphyllum paxianum. Paxiphylline C ( 1 ) represents the first example of Daphniphyllum alkaloids with a carbonyldioxy group. Their structures were elucidated on the basis of spectroscopic data.     

Daphnoldines A and B,Two New Yuzurine Alkaloids with a Four‐Ring System,from the Fruits of Daphniphyllum oldhami

Two new yuzurine alkaloids, daphnoldines A ( 1 ) and B ( 2 ), possessing a rare four‐ring system, were isolated from the fruits of Daphniphyllum oldhami. Their structures were established on the basis of extensive spectroscopic analyses. Daphnoldine A ( 1 ) is the first example of Daphniphyllum alkaloids bearing a hydroxymethyl group at C(14).     

Alkaloids from Fruits of Daphniphyllum oldhamii

Seventeen Daphniphyllum alkaloids, including two new pentacyclic alkaloids, yuzuric acid ( 1 ) and daphnezomic acid ( 2 ), and 15 known ones, were isolated from the fruits of Daphniphyllum oldhamii. The structures and configuration of the two new alkaloids were determined on the basis of spectroscopic methods, especially 2D NMR techniques.