不同土壤类型烟叶组织结构及化学成分的差异比较

为探寻广东南雄紫色土、沙泥田、牛肝土田3种土壤类型上所种烤烟香气风格差异的原因,以粤烟98的中部叶为试验材料,对烟叶生长发育过程中的组织结构、烤后烟叶主要生物碱及常规化合物等化学成分进行了对比分析。结果表明,紫色土上所种烤烟栅栏组织开始快速增厚的时期较早,沙泥田上所种烤烟栅栏组织前期增厚较快而后期较慢,牛肝土田烟叶栅栏组织、海绵组织和叶片厚度均最大,但在前期生长较慢。烟叶烤后（C3F）总糖、还原糖的含量均以沙泥田最高,牛肝土田次之,紫色土最低;而糖碱比则相反。沙泥田上所种烟叶烤后新烟碱含量最高,假木贼碱含量最低;牛肝土田上所得烤烟降烟碱含量最高,新烟碱含量最低;紫色土上烤烟的降烟碱含量最低,而假木贼碱和烟碱含量最高,适于生产优良浓香型香烟。     

小檗属植物中生物碱成分及药理活性研究概述

本文对小檗属植物的生物碱成分及药理活性等方面的研究进行了概述。研究结果表明,小檗属植物主要含有效成分为生物碱类物质,常见类型为原小檗碱型及双苄基异喹啉型生物碱;在药理活性方面,小檗属植物具消炎抗菌、降血压、降血糖、抗心律失常、抗癌等作用。     

Subereamolline A as a Potent Breast Cancer Migration, Invasion and Proliferation Inhibitor and Bioactive Dibrominated Alkaloids from the Red Sea Sponge Pseudoceratina arabica

A new collection of several Red Sea sponges was investigated for the discovery of potential breast cancer migration inhibitors. Extracts of the Verongid sponges Pseudoceratina arabica and Suberea mollis were selected. Bioassay-directed fractionation of both sponges, using the wound-healing assay, resulted into the isolation of several new and known brominated alkaloids. Active fractions of the sponge Pseudoceratina arabica afforded five new alkaloids, ceratinines A–E (2–6), together with the known alkaloids moloka’iamine (1), hydroxymoloka’iamine (7) and moloka’iakitamide (8). The active fraction of the sponge Suberea mollis afforded the three known alkaloids subereamolline A (9), aerothionin (10) and homoaerothionin (11). Ceratinine B (3) possesses an unprecedented 5,7-dibrominated dihydroindole moiety with an epoxy ring on the side chain of a fully substituted aromatic moiety. Ceratinines D (5) and E (6) possess a terminal formamide moiety at the ethylamine side chain. Subereamolline A (9) potently inhibited the migration and invasion of the highly metastatic human breast cancer cells MDA-MB-231 at the nanomolar doses. Subereamolline A and related brominated alkaloids are novel scaffolds appropriate for further future use for the control of metastatic breast cancer.     

均匀设计法提取附子总生物碱的工艺研究

[目的]筛选附子中总生物碱的最佳提取工艺寻找适合工业化生产的操作程序。[方法]采用均匀设计法对中药附子中总生物碱进行提取,以样品总生物碱量为评价指标探讨乙醇提取的浓度、用量和提取时间对总提取量的影响,将优选出的最佳提取工艺条件,与其他文献中所使用的方法进行比较,判断是否适合工业化生产。即用TS-NS系列提取浓缩机组对附子进行提取浓缩,冷冻干燥后溶解并用滴定法测定测定附子中总生物碱的含量。[结果]最佳工艺条件为：提取剂乙醇浓度为85%,附子粒径60目,乙醇用量为药材量的9倍（1∶9,g∶m l）,提取时间为2 h。在此条件下,总生物碱得率为0.312%。[结论]该方法提取效果较好,可用于工业化生产。     

Actions of quinolizidine alkaloids on Periplaneta americana nicotinic acetylcholine receptors

BACKGROUND: Botanical insecticides do not play a major role as crop protectants, but they are beneficial in some applications. The authors investigated the actions of naturally occurring alkaloids on insect nicotinic acetylcholine (ACh) receptors (nAChRs) by evaluating their abilities to inhibit specific binding of [³H]imidacloprid (IMI) to nerve‐cord membranes from Periplaneta americana L. Two alkaloids were also tested for their actions on nAChRs expressed by cockroach neurons using patch‐clamp electrophysiology. RESULTS: Four natural quinolizidine alkaloids (matrine, sophocarpine, cytisine and aloperine) exhibited more than 50% inhibition of [³H]IMI binding at 10 µM , although other compounds were found to have no or low inhibitory activity. The rank order of potency based on concentration–inhibition curves was cytisine > sophocarpine ≥ aloperine ≥ matrine. Patch‐clamp analysis indicated that sophocarpine and aloperine were not agonists of nAChRs expressed in P. americana neurons, yet, at 10 µM , aloperine, but not sophocarpine, suppressed ACh‐induced inward currents significantly. CONCLUSION: Three of the four natural alkaloids tested possess structural moieties that are necessary for interaction with P. americana nAChRs. Aloperine, which possesses a unique structure and showed a distinctive dose–response curve, was found to act as an antagonist. Appropriate modifications of these alkaloids might result in novel insecticidal nAChR ligands. Copyright © 2008 Society of Chemical Industry     

超声法提取骆驼蒿总生物碱的工艺研究

为优化骆驼蒿地上部分总生物碱的提取工艺,在单因素试验的基础上,选取乙醇浓度、提取温度、提取时间3个因素进行正交试验。结果表明:超声提取的影响因素排序为乙醇浓度>提取温度>提取时间;最佳提取条件为10倍量的80%乙醇提取3次,每次50 min,提取温度50℃,总生物碱提取量为1.960 mg.g-1。     

茶树等植物中嘌呤生物碱代谢研究进展

咖啡碱等嘌呤生物碱分布于自然界多种植物中,由于过量摄入咖啡碱会对人体产生副作用,因此对嘌呤碱代谢进行调控,培育低咖啡碱植物品种具有重要的意义。本文综述了嘌呤生物碱在不同属种植物中的分布、生物合成与降解的主要路径及非主要路径、参与嘌呤碱代谢的酶及相应编码基因克隆的研究进展,并对培育低咖啡碱茶树品种中存在的问题与今后的努力方向进行了讨论和展望。     

气-质联用(GC/MS)法测定烟草生物碱的方法优化

采用气相色谱-质谱法(GC/MS),通过优化相关技术参数建立了能够快速准确测定烟草中烟碱和微量生物碱(降烟碱、麦斯明、假木贼碱和新烟草碱)含量的方法.经正交试验确定了超声提取和有机溶剂萃取前处理方法的最佳条件,结果表明:烟碱、降烟碱、麦斯明和假木贼碱的线性范围分别为20～600、30～300、3.2～12、16～60mg/L,检测限分别为0.11、0.09、0.02和0.04mg/kg,回收率介于88.5%～105.4%,相对标准偏差(n=5)介于2.4%～9.2%.该方法具有检测烟草生物碱灵敏度高和重现性好的特点,且操作简便,解决了已有方法存在的生物碱各个组分提取不完全和含量极低的麦斯明检测效果不理想等问题.     

Psammaceratin A: A Cytotoxic Psammaplysin Dimer Featuring an Unprecedented (2Z,3Z)-2,3-Bis(aminomethylene)succinamide Backbone from the Red Sea Sponge Pseudoceratina arabica

Bioassay-guided partition of the extract of the Red Sea sponge Pseudoceratina arabica and HPLC purification of the active fraction gave a psammaplysin dimer, psammaceratin A (1), along with psammaplysin A (2). The dimer comprises two units of psammaplysin A (2) connected via the terminal amines with an unprecedented (2Z,3Z)-2,3-bis(aminomethylene)succinamide moiety, and it represents the first dimer to be identified among the psammaplysin family. Data from 1D- and 2D-NMR and HRMS supported the chemical structures of the compounds. Psammaceratin A (1) and psammaplysin A (2) exhibited significant growth inhibition of HCT 116, HeLa, and MBA-MB-231 cells down to 3.1 μM.     

Inhibitory activities of venom alkaloids of Red Imported Fire Ant against Clavibacter michiganensis subsp. michiganensis in vitro and the application of piperidine alkaloids to manage symptom development of bacterial canker on tomato in the greenhouse

Tomato bacterial canker caused by Clavibacter michiganensis subsp. michiganensis (CMM) is a highly destructive disease that has caused major economic losses in tomato production worldwide. In seeking disease management alternatives, the inhibitory activity of alkaloids extracted from the Red Imported Fire Ant was studied in the laboratory and the greenhouse. Piperidine and piperideine alkaloids each significantly inhibited CMM growth on nutrient agar plates. The inhibitory activity of piperidine alkaloids was stable at 4 ^° C and 22 ^° C for 12 weeks and at 54 ^° C for 4 weeks. The growth of CMM was negatively correlated with the concentration of piperidine alkaloids in nutrient broth. In the greenhouse, piperidine alkaloids also significantly reduced the symptom development on two tomato cultivars, Better Boy and DRK7018F1. This is the first demonstration that piperidine and piperideine alkaloids from the Red Imported Fire Ant are highly inhibitory against a plant-pathogenic bacterium, viz. CMM. Piperidine alkaloids could provide satisfactory management of CMM bacterial canker on tomato seedlings in the greenhouse. Our findings may lead to the development of a new group of bactericides.