In Situ Visual Distribution of Gelsemine,Koumine, and Gelsenicine by MSI in Gelsemium elegans at Different Growth Stages

The distribution of pharmatically important alkaloids gelsemine, koumine, and gelsenicine in Gelsemium elegans tissues is a hot topic attracting research attention. Regretfully, the in planta visual distribution details of these alkaloids are far from clear although several researches reported the alkaloid quantification in G. elegans by LC-MS/MS. In this study, mass imaging spectrometry (MSI) was employed to visualize the in situ visualization of gelsemine, koumine, and gelsenicine in different organs and tissues of G. elegans at different growth stages, and the relative quantification of three alkaloids were performed according to the image brightness intensities captured by the desorption electrospray ionization MSI (DESI-MSI). The results indicated that these alkaloids were mainly accumulated in pith region and gradually decreased from pith to epidermis. Interestingly, three alkaloids were found to be present in higher abundance in the leaf vein. Along with the growth and development, the accumulation of these alkaloids was gradually increased in root and stem. Moreover, we employed LC-MS/MS to quantify three alkaloids and further validated the in situ distributions. The content of koumine reached 249.2 μg/g in mature roots, 272.0 μg/g in mature leaves, and 149.1 μg/g in mature stems, respectively, which is significantly higher than that of gelsemine and gelsenicine in the same organ. This study provided an accurately in situ visualization of gelsemine, koumine, and gelsenicine in G. elegans, and would be helpful for understanding their accumulation in plant and guiding application.     

Erythrina alkaloids from leaves of Erythrina arborescens

Continued interest in Erythrina alkaloids resulted in the isolation of 38 alkaloids including 7 undescribed ones from the leaves of Erythrina arborescens Roxburgh. Among the new compounds, erythrivarines H-I were two dimeric alkaloids, while others were Erythrina alkaloid glucosides. Dimeric Erythrina alkaloids and monomers, turcomanidine and isoboldine, showed medium xanthine oxidase inhibition.     

Alkaloids from Nitraria komarovii. Structures of nitraridine, dihydronitraridine, and tetrahydronitraridine

Three new alkaloids nitraridine (1), dihydronitraridine (2), and tetrahydronitraridine (3) were isolated from the aerial part of Nitraria komarovii. Their structures were established based on chemical transformations and spectral data. The compounds were synthesized. Spectral properties of the komarovine subgroup of alkaloids were discussed. __________ Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 370–372, July–August, 2006.     

Amaryllidaceae,sceletium, imidazole,oxazole, thiazole,peptide and miscellaneous alkaloids

This review covers alkaloids classified in the plant families Amaryallidaceae and Sceletium. In addition alkaloids possessing imidazole, oxazole and thiazole structures are listed followed by alkaloids possessing peptide linkages. Finally miscellaneous alkaloids include those compounds found naturally which cannot be classified into known groups; a relative Pandora's box. A total of 620 structures has been reviewed from 218 references found in the literature for the period July 1999 to June 2000.     

Louis Pasteur,Chemist: An Account of His Studies of Cinchona Alkaloids

Pasteur carried out pioneering work on cinchona alkaloids and their derivatives and his studies led to important discoveries. He examined crystals of cinchona alkaloids for his correlation of crystal hemihedrism with molecular chirality, studies that led Pasteur to the discovery of physicochemical differences between diastereoisomeric salts of tartaric acids with optically active cinchona bases, an important insight into fundamentals of molecular chirality. These physicochemical differences also led to Pasteur’s invention of the vital method of racemate resolution through diastereoisomeric derivatives. Pasteur clarified the confusion around the cinchona alkaloids by elucidating their identities and relations. He discovered the conversion of the major cinchona alkaloids to quinicine and cinchonicine, a finding subsequently of considerable importance in studies of the structure and synthesis of the major cinchona alkaloids. The reaction producing quinicine and cinchonicine led Pasteur to the discovery of the racemization of tartaric acid and the finding of meso‐tartaric acid, fundamental breakthroughs in the development of stereochemistry.     

16-O-去甲基去氧乌头碱在肠内细菌中的生物转化研究

采用人肠内细菌和乌头碱体外温孵的方法,探讨乌头碱的代谢产物16-O-去甲基去氧乌头碱在人肠内的生物转化。利用离子阱电喷雾串联质谱(ESIMS/MSn)方法直接分析16-O-去甲基去氧乌头碱的代谢产物。乌头类生物碱在ESI正离子模式条件下形成质子化分子[M H] 。16-O-去甲基去氧乌头碱可被人肠内细菌转化,通过脱乙酰基、脱苯甲酰基、脱甲基、脱羟基以及酯化反应产生新型的单酯型、双酯型和脂类生物碱等10余种代谢产物。双酯型生物碱具有较高的毒性,相对应的单酯型和脂类生物碱毒性较低。16-O-去甲基去氧乌头碱被肠内细菌转化为单酯型和脂类生物碱会使其毒性降低。     

Review on asymmetric synthetic methodologies for chiral isoquinuclidines; 2008 to date

Isoquinuclidines constitute the central structural nucleus of numerous biologically active natural products, for example, iboga alkaloids such as ibogamine and catharanthine as well as non-indole-containing alkaloids such as the dioscorine and the cannivonines. Furthermore, in medicinal and pharmaceutical chemistry, the isoquinuclidine core is commonly employed as a rigid azabicyclic scaffold, thus providing significant precursors in the synthesis of numerous valuable alkaloids. Summarizing well-organized approaches to access the chiral isoquinuclidine structural centerpiece signifies a significant endeavor not only for developing biologically active natural products but also enhancing biological researches that can lead to possible drug discovery. Over time, the values and methodologies for the asymmetric synthesis of chiral isoquinuclidines are increasing; hence to advance asymmetric synthesis, this review combines and discusses the pros and cons of each synthesis techniques from 2008. This review should be helpful for promoting further developments of asymmetric synthetic methodologies and for medicinal chemistry.     

The application of thin-layer chromatography and phosphorimetry for the rapid determination of nicotine,nornicotine, and anabasine in tobacco

Tobacco is ground and extracted with chloroform, and thin-layer chromatography is used to separate the 3 major tobacco alkaloids—nicotine, nornicotine and anabasine. Each of the alkaloids is quantitatively removed by scraping the spot into a container and dissolving in ethanol-sulfuric acid. A small volume of the ethanol solution is then measured phosphorimetrically. Excellent recoveries of each of the tobacco alkaloids were obtained; the relative standard deviation of analysis was 6% or less for all analyses. The total time for analysis of the 3 alkaloids was less than 90 min. This method is considerably faster and more accurate than previous methods.     

Biphenyl ether and biphenyl quinolizidine lactone alkaloids from Heimia salicifolia

Three new biphenyl ether quinolizidine lactone alkaloids (1–3) and 13 new biphenyl quinolizidine lactone alkaloids (4–16) were isolated from Heimia salicifolia (Lythraceae) together with seven known alkaloids. Their structures were determined by spectroscopic analyses and chemical conversions.     

Demethoxylation and O-Demethylation of Pseudaconine and Isotalatizidine

Thenorditerpenoidalkaloidsnotonlyhaveimportantpharmacologicalactivities,butalsomaysetoffalotofinterestingchemicalreactionsl'2.Inthecourseofourstudiesonsearchforhighactivity,lowtoxicitycompoundsandconversionoftheskeletons,aseriesofmodificationsofthesealkaloidshavebeenreported'.Inthepresentpaper,wereportsomechemicalreactionsincludingthedemethoxylation,O-demethylationandoxidation,ofthenorditerpenoidalkaloidspseudaconine1andisotalatizidine7.Treatmentofthenorditerpenoidalkaloidscontainingmethoxylgr…     

Spectrophotometric determination of atropine, pilocarpine and strychnine with chloranilic acid

In dioxan-chloroform medium the acceptor chloranilic acid forms 1:1 molecular complexes with the alkaloids atropine, pilocarpine and strychnine, with maximum absorption at 535, 527.5 and 535 nm respectively. Conformity with Beer's law allows the use of the complexes for the assay of these drugs.     

Three new C_(20)-diterpenoid alkaloids from Delphinium anthriscifolium var.savatieri

Three new C20-diterpenoid alkaloids, designated as anthriscifolmines A-C (1-3), together with two known alkaloids denudatine and delgramine, were isolated from the whole herb of Delphinium anthriscifolium var. savatieri. The structures of these new alkaloids were elucidated on the basis of spectral data.     

Synthesis of the tricyclic indole alkaloids,dilemmaones A and B

Dilemmaones A-C are naturally occurring tricyclic indole alkaloids possessing a unique hydroxymethylene or methoxymethylene substituent at the C2 position of the indole core and a C6–C7 fused cyclopentanone. Dilemmaone B has been prepared in 5 steps from 5-methylindan-1-one, and dilemmaone A has been prepared in 3 steps from a common precursor, 6-bromo-5-methyl-7-nitroindan-1-one. In both syntheses, key steps include a Kosugi-Migita-Stille cross coupling and a reductive cyclization using hydrogen gas and a transition metal catalyst.     

Separation of cinchona alkaloids, opium alkaloids, heroin, and related narcotics by dynamic-coating high-speed liquid chromaotgraphy

High-speed liquid chromatography can provide successful separations of two cinchona alkaloids, four opium alkaloids, or heroin-related narcotics. Poly G-300 is used as the liquid stationary phase. Both mechanical-coating and dynamic-coating techniques are employed; dynamic-coating techniques appear to be advantageous for some cases. With the latter technique the degree of partition and adsorption separation mechanisms can be controlled to facilitate separations which might be difficult otherwise. Quantitative analysis of three rapidly eluting opium alkaloids, at nanogram to microgram levels, is described; reasonable accuracy (± 10% or better) was obtained.     

Rapid thin-layer chromatographic separation of cocaine from codeine,heroin, 6-monoacetylmorphine,morphine and quinine on microscope slides

A thin-layer chromatographic method is reported for the separation of cocaine from codeine, heroin, 6-monoacetylmorphine, morphine and quinine on microscope slides. The method involves the use of sodium hydroxide-impregnated silica gel G microchromatoplates and acetone-benzene (50:50) as developer. Cocaine separates as a distinct spot while quinine and the morphinoid alkaloids separate collectively as one large spot near the point of application. Preliminary data suggest that the procedure will separate cocaine from aspirin and caffeine, and also from mixtures containing aspirin, caffeine, quinine, codeine, heroin. 6-monoacetylmorphine and morphine.     

Systematic screening and characterization of tertiary and quaternary alkaloids from corydalis yanhusuoW.T. Wang using ultra-performance liquid chromatography-quadrupole-time-of-flight mass spectrometry

Ultra-performance liquid chromatography-quadrupole-time-of-flight mass spectrometry (UPLC-Q-TOF-MS) is an effective technique for analysis of complex samples with offering rapid, efficient separation in combination with accurate mass measurement and tandem mass spectrometry (MS/MS). This paper exploits this technique to identify the alkaloids in corydalis yanhusuo, an important antalgic Traditional Chinese Medicine (TCM). The mass spectral fragmentation behavior of one tertiary alkaloid and two quaternary alkaloids was studied in detail. Low-abundance product ions of tertiary and quaternary alkaloids were investigated and compared between each other. Sixteen alkaloids were screened out by using a systematic screening method developed in our laboratory; structures of eight therein were identified by characteristic UV absorption spectrum and positive ion mode of Q-TOF-MS/MS; and two of them were discovered for the first time in corydalis yanhusuo to our knowledge. This research demonstrates the potential of UPLC-Q-TOF-MS in structural characterization and identification of components in traditional Chinese herbal medicines.     

An easy route to exotic 9-epimers of 9-amino-(9-deoxy) cinchona alkaloids with(8S,9R) and(8R,9S)-configurations through two inversions of configuration

Four exotic chiral organocatalysts, 9-amino-（9-deoxy） cinchona alkaloids with （8S, 9R） and （8R, 9S）- configurations, were conveniently synthesized for the first time in 27-72% total yields through two conversions of configuration at the 9-stereogenic centers of commercially available cinchona alkaloids.     

西藜芦生物硷~1H核磁共振谱的研究

本文研究了西藜芦生物硷的1~H核磁共振谱,归纳出一些确定酰基连接位置的初步规律。     

Sensitive determination of pyrrolizidine alkaloids in Tussilago farfara L. by field‐amplified,sample‐stacking,sweeping micellar electrokinetic chromatography

Pyrrolizidine alkaloids are the toxic components in Tussilago farfara L. Due to the lack of standard substances for quantitative analysis and traces of pyrrolizidine alkaloids in total alkaloids, the full quality control of Tussilago farfara L has been limited. In this study, we aimed to solve the difficulty of determination of pyrrolizidine alkaloids and identify more components in the total alkaloids. An on‐line preconcentration method has been applied to improve determining sensitivity of pyrrolizidine alkaloids in Tussilago farfara L. in which included field‐amplified sample stacking and sweeping in micellar electrokinetic capillary chromatography. The main parameters that affected separation and stacking efficiency were investigated in details. Under the optimal conditions, the sensitivity enhancement factors obtained by the developed method for the analytes were from 15‐ to 12‐fold, the limits of detection of senkirkine and senecionine were 2～5 μg/L. Senkirkine and senecionine have been detected in alkaloids ( c ) of Tussilago farfara L, along ferulic acid methyl ester and methyl caffeate. The developed method was also applied to the analysis of acid extraction ( a ) of Tussilago farfara L, and senkirkine could be detected directly. The results indicated that the developed method is feasible for the analysis of pyrrolizidine alkaloids in Tussilago farfara L with good recoveries.     

Synthesis, structure and stereochemistry of quinoline alkaloids from Choisya ternata

A range of seventeen quinoline alkaloids, involving several types of oxidations during their biosynthetic pathways, have been isolated from leaves of Choisya ternata. In addition to the nine known quinoline alkaloids, eight new members of the furoquinoline family, derived mainly from prenylation at C-5 (including two novel hydroperoxides), have been identified. The absolute configurations and enantiopurity values of all chiral quinoline alkaloids have been determined. One of the isolated alkaloids, 7-isopentenyloxy-gamma-fagarine, has been used as a precursor for the chemical asymmetric synthesis of the enantiopure alkaloids: evoxine, anhydroevoxine and evodine. The possible roles of oxygenase and other oxygen-atom-transfer enzymes, in the biosynthetic pathways of the C. ternata alkaloids, have been discussed.