露蕊乌头总生物碱提取工艺的优化研究

[目的]优选露蕊乌头药材中总生物碱的提取工艺。[方法]以提取物得率和乌头碱的含量为考察指标,采用L9(34)正交试验法探讨温度、浸润时间和超声波提取时间等因素对总生物碱提取的影响,并利用中和法测定总生物碱的含量。[结果]影响露蕊乌头总生物碱提取含量的各因素主次顺序为超声波提取时间(C)>浸润时间(B)>温度(A);最佳提取工艺条件为:A3B3C2,即温度80℃,浸润时间36 h,超声波处理30 min;在此条件下,乌头碱的含量最高。[结论]该方法简便快捷,稳定性好,提取工艺有一定的特异性,且在操作流程中减少了乌头碱有效成分的损失。该方法优化了露蕊乌头总生物碱的提取工艺,为露蕊乌头总生物碱的进一步研究奠定了基础。     

Bioassay‐guided isolation and identification of active compounds from Macleaya microcarpa (Maxim) Fedde against fish pathogenic bacteria

Four alkaloids (Sanguinarine, 6‐Methoxyl‐dihydro‐chelerythrine, Cryptopine and β‐Allocryptopine) were isolated from aerial parts of Macleaya microcarpa (Maxim) Fedde using bioassay‐guided isolation method, and the inhibitory activity of ethanolic extract, various fractions and these four alkaloids against four fish pathogenic bacteria (Aeromonas hydrophila, Aeromonas salmonicida, Vibrio anguillarum and Vibrio harveyi) was assessed in vitro using the agar dilution method and the microdilution assay method respectively. A. hydrophila was the most sensitive strain to all the tested compounds. Minimum inhibitory concentration (MIC) values were lower for sanguinarine against all tested Gram‐negative strains than other three alkaloids, with MIC values of 12.5 mg L^?1 for A. hydrophila and 50 mg L^?1 to other pathogenic bacteria. Followed by 6‐methoxyl‐dihydro‐chelerythrine, which showed considerable antibacterial activity with MIC values of 80 mg L^?1 for A. hydrophila, 100 mg L^?1 for V. harveyi, and 125 mg L^?1 for both V. anguillarum and A. salmonicida. Cryptopine and β‐allocryptopine revealed similar inhibitory activity with MIC values of 100 mg L^?1 for A. hydrophila and 200 mg L^?1 for other three bacterial species. These finding provided evidence that extract, as well as isolated compounds from M. microcarpa might be potential sources novel antibacterial agents for the treatment of fish infectious diseases.     

A Practical Strategy to Discover New Antitumor Compounds by Activating Silent Metabolite Production in Fungi by Diethyl Sulphate Mutagenesis

Many fungal biosynthetic pathways are silent in standard culture conditions, and activation of the silent pathways may enable access to new metabolites with antitumor activities. The aim of the present study was to develop a practical strategy for microbial chemists to access silent metabolites in fungi. We demonstrated this strategy using a marine-derived fungus Penicillium purpurogenum G59 and a modified diethyl sulphate mutagenesis procedure. Using this strategy, we discovered four new antitumor compounds named penicimutanolone (1), penicimutanin A (2), penicimutanin B (3), and penicimutatin (4). Structures of the new compounds were elucidated by spectroscopic methods, especially extensive 2D NMR analysis. Antitumor activities were assayed by the MTT method using human cancer cell lines. Bioassays and HPLC-photodiode array detector (PDAD)-UV and HPLC-electron spray ionization (ESI)-MS analyses were used to estimate the activated secondary metabolite production. Compounds 2 and 3 had novel structures, and 1 was a new compound belonging to a class of very rare natural products from which only four members are so far known. Compounds 1–3 inhibited several human cancer cell lines with IC₅₀ values lower than 20 μM, and 4 inhibited the cell lines to some extent. These results demonstrated the effectiveness of this strategy to discover new compounds by activating silent fungal metabolic pathways. These discoveries provide rationale for the increased use of chemical mutagenesis strategies in silent fungal metabolite studies.     

Progress in NMR-based metabolomics of Catharanthus roseus

Metabolomics has been rapidly developed as an important field in plant sciences and natural products chemistry. As the only natural source for a diversity of monoterpenoid indole alkaloids (MIAs), especially the low-abundance antitumor agents vinblastine and vincristine, Catharanthus roseus is highly valued and has been studied extensively as a model for medicinal plants improvement. Due to multistep enzymatic biosynthesis and complex regulation, genetic modification in the MIA pathway has resulted in complicated changes of both secondary and primary metabolism in C. roseus, affecting not only the MIA pathway but also other pathways. Research at the metabolic level is necessary to increase knowledge on the genetic regulation of the whole metabolic network connected to MIA biosynthesis. Nuclear magnetic resonance (NMR) is a very suitable and powerful complementary technique for the identification and quantification of metabolites in the plant matrix. NMR-based metabolomics has been used in studies of C. roseus for pathway elucidation, understanding stress responses, classification among different cultivars, safety and quality controls of transgenic plants, cross talk between pathways, and diversion of carbon fluxes, with the aim of fully unravelling MIA biosynthesis, its regulation and the function of the alkaloids in the plant from a systems biology point of view.     

天南星科植物生物碱成分研究进展

总结了天南星科植物含有的生物碱类型主要包括吡咯和四氢吡咯类、吡啶和哌啶类、环二肽类、哌嗪类、吲哚和β-咔啉类、Homonojirimycin类生物碱,且此类次生代谢产物具有细胞毒与抗肿瘤、抗菌、抗氧化、抗凝血、昆虫毒杀以及糖苷酶抑制等活性,针对天南星科植物资源开发利用过程中存在的问题提出相应的建议,为该科植物资源的进一步研究与开发提供参考。     

中心组合设计-响应面分析法优选平贝母总生物碱

为了优化平贝母中总生物碱的提取工艺,采用中心组合设计方法,研究乙醇浓度、超声时间、液固比及其交互作用对总生物碱提取率的影响。应用SAS软件和响应面分析相结合的方法,模拟得到回归方程的预测模型和可信度,并通过岭脊分析得到最佳的提取条件为：乙醇浓度81.4%、超声时间74.9 min、液固比30.9 mL/g。该条件下提取率为0.158%。该实验研究,为平贝母总生物碱的工业化生产提供了必要的技术支持。     

Potential of gamma radiation enhancing the biosynthesis of tropane alkaloids in black henbane (Hyoscyamus niger L.)

Summary A productive yellow flowered mutant with high tropane alkaloid content was isolated in the M₂ generation of gamma irradiated (Co⁶⁰ at 40 kr) progenies ofHyoscyamus niger. Mutant progenies, on an average, were capable of synthetising more than twice crude alkaloid (0.147% to 0.221%) in M₃ through M₆ generations compared to the parental control (0.065 to 0.106%). In pilot scale trial (M₇), two elite lines, Y-15 and Y-17 were found to contain 0.390% and 0.318% crude drug in contrast to 0.211% in an improved inbred used as control. However, owing to conducive plant morphology, Y-17 registered high yield of dry biomass, hence gave more than double yield of crude drug than the improved control (inbred) (23 kg/ha against 11 kg/ha). Also being superior in hyoscyamine and hyoscine yields, it was redesignated as var.Aela, and released for commercial cultivation in India, thus signifying the efficiency of radiation breeding for crop improvement.     

低海拔引种栽培玛咖主要有效成分分析

为给低海拔地区栽培玛咖的开发和推广提供参考依据,以引种栽培基地湖南省湘西自治州不同海拔样地的玛咖为材料,采用醇浸取法和高效液相色谱法,对其生物碱、玛咖酰胺和玛咖烯等主要有效成分进行了测定与分析。测定结果表明:其总生物碱含量为0.707%~2.376%;玛咖酰胺含量为0.083 8%~0.529 2%,玛咖烯含量为0.008 3%~0.070 6%,玛咖酰胺+玛咖烯含量为0.099 7%~0.537 6%。分析结果表明:湘西低海拔地区栽培的玛咖其主要有效成分含量与秘鲁原产地的相当,说明海拔高度对玛咖有效成分含量无显著影响。文中因此认为,玛咖可以在低海拔地区大量推广栽培。     

雷公藤总生物碱的提取及对东亚飞蝗的生物活性检测

提取、分离了雷公藤Tripterygium wilfordii根皮中总生物碱物质,采用小叶蝶添加法测定其对东亚飞蝗Locustas migratoria拒食、生长发育及毒杀等生物活性.结果表明:雷公藤总生物碱对3龄东亚飞蝗具有拒食、生长发育抑制和毒杀作用.48 h非选择性拒食中浓度AFC_(50)、生长发育抑制中浓度EC_(50)48 h毒杀中浓度LC_(50)分别为236.84 mg/L、151.96 mg/L和171.72 mg/L;雷公藤总生物碱对东亚飞蝗无明显触杀作用.     

石蒜属植物生物碱类化合物及其构效关系研究进展

石蒜属植物因其丰富的生物碱类型及多种药理活性,受到了国内外学者的广泛关注。研究表 明,石蒜属植物碱主要含有 7 类,具有抗肿瘤、抗疟疾、抗 AChE、抗菌、抗病毒、抗抑郁症、降血压等 多种药理活性。文章对 10 种石蒜属植物所含生物碱种类、数量、药理作用等研究现状进行综述,并重点 关注石蒜属生物碱的结构与药理活性之间的构效关系。