Pubescine A,a cyclopeptide alkaloid from Discaria pubescens

From Discaria pubescens, a new peptide alkaloid, pubescine A (1), belonging to the frangulanine type has been isolated and its structure elucidated. Pubescine A seems to be isomeric to melonovine A. For the first time, d-leucine has been identified in a cyclopeptide alkaloid.     

Laboratory-scale production of (S)-reticuline,an important intermediate of benzylisoquinoline alkaloids,using a bacterial-based method

Benzylisoquinoline alkaloids (BIAs) are a group of plant secondary metabolites that have been identified as targets for drug discovery because of their diverse pharmaceutical activities. Well-known BIAs are relatively abundant in plants and have therefore been extensively studied. However, although unknown BIAs are also thought to have valuable activities, they are difficult to obtain because the raw materials are present at low abundance in nature. We have previously reported the fermentative production of an important intermediate (S)-reticuline from dopamine using Escherichia coli. However, the yield is typically limited. Here, we improved production efficiency by combining in vivo tetrahydropapaveroline production in E. coli with in vitro enzymatic synthesis of (S)-reticuline. Finally, 593 mg of pure (S)-reticuline was obtained from 1 L of the reaction mixture. Because this bacterial-based method is simple, it could be widely used for production of (S)-reticuline and related BIAs, thereby facilitating studies of BIAs for drug discovery.     

C19-、C20-二萜生物碱抗肿瘤活性研究进展

二萜生物碱具有较高的药理活性和药用价值，一直以来为药理学家和临床医生所重视，但对于其抗肿瘤作用的报道却并不多见，主 要集中于 C19-、C20- 二萜生物碱。综述近 10 年来 C19-、C20- 二萜生物碱抗肿瘤作用的基础及临床研究进展，并对当前研究存在的不足提出 见解，为进一步研究及应用提供参考。     

Biosynthesis of gramine in Phalaris arundinacea

The administration of L-tryptophan-[3-¹⁴C] to Phalaris arundinacea L. (Vantage strain) for 9 days resulted in the formation of radioactive gramine (8.2% absolute incorporation). A systematic degradation of the alkaloid indicated that essentially all its activity was located on the methylene group, indicating that its biosynthesis is the same as that occurring in Hordeum species and Lupinus hartwegii.     

Discovery of conolidine derivative DS39201083 as a potent novel analgesic without mu opioid agonist activity

We discovered a novel compound, 5-methyl-1,4,5,7-tetrahydro-2,5-ethanoazocino[4,3-b]indol-6(3H)-one sulfuric acid salt (DS39201083), which was formed by derivatization of a natural product, conolidine. DS39201083 had a unique bicyclic skeleton and was a more potent analgesic than conolidine, as revealed in the acetic acid-induced writhing test and formalin test in ddY mice. The compound showed no agonist activity at the mu opioid receptor.     

不同地区草乌种子中生物碱含量的测定与分析

测定不同产地野生草乌（Aconitum kusnezoffii Reichb.）种子中生物碱类含量，并与草乌入药部分（块根、叶）生物碱含量做对比。采用HPLC法测定了内蒙古通辽市扎鲁特旗、赤峰市阿鲁科尔沁旗和赤峰市巴林右旗野生草乌的种子，色谱柱Supersil ODS2 5 μm（250 mm×4.6 mm，5 μm），流动相为甲醇-0.1 mol·L^-1：三乙胺（75：25），流速为0.8 mL·min^-1，检测波长为235 nm，柱温为35℃。草乌种子中检测到生物碱类，以苯甲酰新乌头原碱含量最高。通辽市扎鲁特旗种子含量为7.647 9 mg·g^-1；赤峰市阿鲁科尔沁旗种子含量为8.256 3 mg·g^-1；赤峰市巴林右旗种子含量为7.512 6 mg·g^-1，双酯型生物碱含量较低。不同产地的总乌头碱含量通辽市的高于赤峰市的，同为赤峰市含量之间显著差异。相关文献报道草乌药材（块根）中双酯型生物碱的含量明显高于单酯型生物碱，本研究实验表明，不同地区草乌种子中单酯型生物碱的含量明显高于双酯型生物碱，为草乌种子的综合利用开发及筛选不同含量种质材料提供理论依据。     

A New Monoterpene Alkaloid from Incarvillea sinensis with Migration Inhibitory Activity on Cancer Cell

A novel monoterpene alkaloid, named incarvine G, was isolated from the Incarvillea sinensis Lam. Its chemical structure was elucidated using comprehensive spectroscopic methods. Incarvine G is an ester compound comprised of a monoterpene alkaloid and glucose. This compound showed evident inhibition on cell migration, invasion, and cytoskeleton formation of human MDA-MB-231 with low cytotoxicity.     

Determination of the relative rates of incorporation of arginine and ornithine into retronecine during pyrrolizidine alkaloid biosynthesis

A double-isotope technique for simultaneously measuring the per cent incorporation of two precursors into a metabolite is described. The method has been used to show that ornithine is a more efficient precursor than arginine for the biosynthesis of retronecine, the necine base component of the pyrrolizidine alkaloid senecionine.