A mass spectrometric investigation of alkaloids of the galanthamine type

Conclusions 1. Features of the mass spectrometric behavior of alkaloids of the galanthamine type have been established: the presence of strong M⁺ and M — 1 peaks, the contraction of ring C with the retention or with the expulsion of the nitrogen atom, and the elimination of the elements of ring B.2. Additional information on the structure of the alkaloid chlidanthine has been obtained.3. The similarity of the mass spectrometric behavior of a dihydro derivative of galanthamine (lycoramine) and of dihydro derivatives of alkaloids of the lycorine type have been shown.Khimiya Prirodnykh Soedinenii, Vol. 5, No. 5, pp. 280–283, 1969     

B/E linked scanning spectra of the molecular and fragmentary ions of lycoctonine bases

The B/E linked scanning spectra of the M⁺, (M-15)⁺, and (M-OR₁)⁺ ions and those of some other series have been investigated. The characteristic nature of the individual intensities of the metastable peaks (the magnitudes A) with the same R₁ radicals for different groups of alkaloids has been shown for the spectra of the M⁺ and (M-15)⁺ ions. The reason for the quantitative differences of the B/E spectra of the (M-OH)⁺ ions from the spectra of the (M-OCH₃)⁺ and (M-OAc)⁺ ions, consisting in the influence of alternative methods of eliminating an OH radical, has been found. It has been confirmed that the values of A of analogous transitions calculated from the B/E and MD spectra are close to one another. On the other hand, the values of the energy of the metastable transitions obtained by these two methods differ from one another by two orders of magnitude.Institute of Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Special Design Bureau of Analytical Instrument Construction, Scientific and Technical Branch, Academy of Sciences of the USSR, Leningrad. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 72–84, January–February, 1991.     

Capillary isotachophoresis of some isoquinoline alkaloids

The isotachophoretic behavior of quaternary benzo/c/phenanthridine, protoberberine and aporphine alkaloids in different electrolyte systems is described. The concentration of the leading ion and the pH value of the leading electrolyte affect the relative effective mobilities of the alkaloids. The system of pH 4.7, containing the leading ion K⁺ (0.005 M) counter ion acetate, and the terminating ion β-alanine (0.02 M), has been selected for the quantitative determination of the studied alkaloids in model mixtures and plant extracts.     

Comparison of different HPLC systems for analysis of galantamine and lycorine in various species of Amaryllidaceae family

Retention parameters of galantamine and lycorine standards were determined on different columns, i.e., octadecyl silica, SM C18, and strong cation-exchange (SCX) columns with different aqueous mobile phases. Retention of alkaloids was investigated on C18, SM C18 columns with mobile phase containing 5% MeCN, 20% acetate buffer at pH 3.5, and 0.025 ML^?1 diethylamine (DEA), and on SCX column with mobile phase containing 8% MeCN and phosphate buffer at pH 2.5. Better results were also obtained in ion-exchange chromatographic system. On the basis of results obtained in different chromatographic systems, simple, rapid, and sensitive high-performance liquid chromatography methods were developed for determining lycorine and galantamine in plant extracts from various species belonging to Amaryllidaceae family. Extracts were prepared from various parts of plants collected at different times of the growing season.     

Mass spectra of dihydro derivatives of alkaloids of the lycorine type

Conclusions The mass spectra of dihydrolycorine, diacetylidhydrolycorine, dihydroungminorine, diacetyldihydroungminorine, and diacetyldihydroungminorinone have been studied.The fragmentation of these compounds differs from that of alkaloids of the lycorine type only by the absence of a retrodiene type of decomposition.Khimiya Prirodnykh Soedinenii, Vol. 4, No. 4, pp. 227–230, 1968     

Mass Spectral fragmentation patterns of heterocycles. V . Electron impact promoted mass spectral fragmentation of indolo[1,7-ab][1]benzazepine and Some of its Derivatives

The fragmentation patterns of 1,2,6,7-tetrahydroindolo[1,7-ab][l]benzazepin-1-one ( 1 ), 6,7-dihydroindolo-[1,7-ab][l]benzazepine ( 2 ) and indolo[1,7-ab][1]benzazepine ( 3 ) on electron impact have been examined. Loss of carbon monoxide to form the base peak at m/e 207 and loss of CHO radical to give m/e 206 consititute the major fragmentation pathways for 1. The moleclar ions ( M ⁺) are abundant for each of the compounds; observed as the second most intense peak for 1 (85% relative intensity) and the base peaks for 2 and 3 . The spectrum of 2 is characterized by intense M-1 and M-2 ions and by the presence of a M-15 ion (m/e 204) of moderate intensity (11.4%). In all other respects the spectra of 2 and 3 are strikingly similar. The M-15 ion from 2 , assigned the heteroaromatic pyrroloacridinium structure, is also formed in the spectrum of 1. A second heteroaromatic ion at m/e 191, common to the spectra of 1 , 2 and 3 , is believed to have the pyrrolocarbazol-ium structure. Metastable ion transitions and exact mass measurements support most of the proposed fragmentation pathways and structural assignments.     

Synthesis and mass spectra of some 1-aroylamino-5-arylaminomethyl-1,2,3-triazoles

The title compounds 2 are prepared from the reaction of 1-(N, N-diaroyl)amino-5-bromomethyl-1,2,3-triazoles with aromatic amines. The fragmentation pattern upon electron impact at 70 eV of compounds 2 is studied. The molecular ion peak is present in all the spectra examined. Besides the [M-28]⁺⁺, there is also a more abundant [M-29]⁺ peak, corresponding to a N₂H loss of the molecular ion. The ion Ar²NH = CH₂ is the base or the most prominent peak.     

Catalytic Asymmetric Assembly of Octahydroindolones: Divergent Synthesis of Lycorine‐type Amaryllidaceae Alkaloids (+)‐α‐Lycorane and (+)‐Lycorine

We report the first catalytic asymmetric approach to octahydroindolones and a divergent enantioselective synthesis of perhydroindole alkaloids, as exemplified by lycorine‐type Amaryllidaceae alkaloids (+)‐α‐lycorane and (+)‐lycorine, from a common intermediate by using a highly concise route. The assembly of octahydroindolones employs a catalytic enantioselective 1,4‐conjugate addition of nitro dienynes, followed by a TsOH‐catalyzed cascade synthesis of highly functionalized enones, and a diastereoselective intramolecular Michael addition.     

Piperaceae alkaloids: Part IV. Structure and Synthesis of Cyclostachine A,Cyclostachine B and Cyclopiperstachine

Three new alkaloids designated as cyclostachine A (2), cyclostachine B (7) and cyclopiperstachine (10) have been isolated from Piper trichostachyon C. DC. Their structures have been derived on the basis of spectral and degradative studies and confirmed by synthesis. The ¹H- and ¹³C-NMR. spectra of these compounds are discussed.     

Simultaneous determination of galanthamine and lycorine in Lycoris radiata by a capillary electrophoresis with an electrochemiluminescence method

A novel capillary electrophoresis with electrochemiluminescence determination method was developed for the determination of two alkaloids based on the electrochemiluminescence signal enhancement effect of the tertiary amine group on tris(2,2′‐bipyridyl)ruthenium(II). A linear relationship between the electrochemiluminescence peak area and concentrations of galanthamine and lycorine in the range of 0.07 ～ 17 μg/mL and 0.07 ～ 18 μg/mL was obtained and the detection limit was 0.008 and 0.002 μg/mL, respectively. The method is selective, simple, and convenient. It had been successfully applied to the analysis of galanthamine and lycorine in Lycoris radiata samples purchased from a local market.     

高效液相色谱法测定石蒜中加兰他敏、力可拉敏及石蒜碱3种生物碱

以石蒜鳞茎为材料,建立了石蒜生物碱的反相高效液相色谱(HPLC)分析方法。探讨了流动相中乙腈含量、三乙胺含量、pH值、流速等对生物碱分离的影响,结果表明在ZORBAX ODS-C18(150 mm×4.6mm,5μm)反相色谱柱上,以0.9%三乙胺水溶液(pH 8.0)-乙腈-甲醇为流动相,梯度洗脱,流速为1mL/min,检测波长为234 nm时,石蒜样品可有效分离出14种石蒜生物碱,分离度良好。加兰他敏、力可拉敏和石蒜碱的检出限分别为3.375、0.475、0.495 mg/L,平均加标回收率均为98%。运用此法测定了石蒜不同部位中3种生物碱的含量,结果表明石蒜不同部位的3种生物碱含量差异较大,叶子中的含量最高;同一部位中,石蒜碱的含量最高,力可拉敏次之,加兰他敏最低。     

Pressurized liquid extraction and anticholinesterase activity-based thin-layer chromatography with bioautography of Amaryllidaceae alkaloids

Modern extraction technique-pressurized liquid extraction (PLE) was optimised for extraction of lycorine and galanthamine (Amaryllidaceae alkaloids) from Narcissus jonquilla ‘Pipit’. Crude extracts were purified on Oasis MCX cartridges, and the alkaloids eluted with 80-100% recoveries using methanol-10% ammonia solution (3:1, v/v). Quantitative results were obtained by both HPTLC-densitometry on silica gel plates and RP-HPLC with diode array (DAD) on XTerra C₁₈ stationary phase. Both methods were fully validated in terms of specificity, precision (including intra- and inter-day measurements), LOD and LOQ values, correlation of UV spectra and linearity of calibration curves. The methods were also well correlated each other with correlation coefficients (r) 0.98823 and 0.99081, respectively, for the mean values of galanthamine and lycorine.Among the investigated solvents methanol and 1% tartaric acid methanolic solution at default conditions (120 °C, p = 60 bar, time: 10 min, one static cycle) permit the highest yields of the total sum of the alkaloids, whereas for toluene the lowest amounts were measured. Lycorine to galanthamine mean ratios were dependant on the type of solvent used, and in toluene galanthamine and related alkaloids were preferably extracted.In temperature experiments for galanthamine, the levels of this compound increased from the temperature of 20 till 150 °C in the investigated solvent systems, then decreased with slight increase from the temperature of 175 to 200 °C in 1% tartaric acid methanolic solution. When lycorine was analysed, similar trends were observed, however the maximum of the concentration was measured at a temperature about 125 °C. The ratios of the mean values of these two compounds differed in temperature-dependant experiments in both solvent systems.Further more, two TLC with bioautography approaches were used in screening for anticholinesterese properties of the extracts. No qualitative differences were found among the different solvent extracts, and AChE inhibition was correlated with galanthamine and related compounds.In conclusion, optimised PLE was much more effective than previously applied hot-solvent extraction, microwave-assisted extraction (MAE) or ultrasound-assisted extraction (USAE).     

Energetics of model compounds of water oxidizing complex containing quinone cofactors

To reveal reaction mechanism of PS-II, the reaction products of photolysis may be compared with their thermolytic products. According to required molecular assemblies in manganese clusters at WOC of PS-II, we have strategically synthesized dimers (M-1, M-2), trimers (M-3A, M-3B) and tetramer (M-4) using spin carrier imino-phenol functionalized ligands viz. Lawsone Oxime (L-1) and Phthiocol Oxime (L-2) of naturally occurring quinones .These are characterized by elemental analyses, thermogravimetric analyses, differential thermal analyses, powder X-ray diffraction and infrared spectroscopy. Stabilization energies for molecular associations of ligands in various redox and stereoisomeric forms via hydrogen bondings are compared with thermal energies required for their expulsion from the coordination polymers calculated with the help of Coats and Redfern’s relation of rising temperatures. Activation energy required for establishing tetramer (M-4) and dimer (M-2) in coordination sphere by counter ion using same synthetic route is found to be comparable (~37.48±1 kJ mol^-1). Quantitized energies from TG-DTA data for valence tautomers of redox active ligands play significant role in formation of resultant model compound. viz. tetramer, dimer of dimer and trimer. The role of oxo, acetato and spin carrier ligands in model cluster compounds are proposed with respect to their expulsion energies.     

Evaluation of fast atom bombardment mass spectrometric and low-energy collisional activation tandem mass spectrometric data for the structural elucidation of bisbenzylisoquinoline alkaloids

The fast atom bombardment (FAB) mass spectra and low-energy collisional activation mass spectra of ions generated under FAB were investigated for twelve bisbenzylisoquinoline (BBI) alkaloids. The relative molecular mass of the free base and diquaternary BBI alkaloids can be obtained from FAB data. However, monoquaternary ammonium salts produce only an [M — X]⁺ ion and the relative molecular mass cannot be determined. For Type A (single ether linkage) BBI alkaloids, fragmentation occurs primarily from benzylic and ether cleavages. Thus, the total number of aromatic substituents (OH, OCH₃ or OCH₂O) can be determined for rings A-B, C-D, E and F. For Type B (two either linkages) BBI alkaloids, fragmentation occurs primarily from double benzylic cleavages. Hence only the total number of aromatic substituents can be determined for the upper half of the Type B BBI alkaloids, i.e. rings A-B and C-D. An unknown alkaloid was examined to illustrate the utility of the fragmentation schemes.     

Strained heterocyclic systems. VII. The mass spectral fragmentations of dihydrocycloalka[b]quinolines and quinoline N-Oxides

High resolution mass spectra of compounds 1-6 were investigated. The quinolines ( 1-3 ) all exhibit a prominent (M-1)⁺ peak and subsequent loss of HCN. These processes are consistent with azatropylium ion intermediates. The N-oxides ( 4-6 ) all exhibit major peaks at (M-16)⁺; the abundance of the latter is related to the geometry of the molecule. The four-membered ring compounds (3 and 6) give more complex spectra, which reflect the influence of the fused strained ring.     

Identification and Determination of <em>Aconitum</em> Alkaloids in <em>Aconitum</em> Herbs and <em>Xiaohuoluo Pill</em> Using UPLC-ESI-MS

A rapid, specific, and sensitive ultra-performance liquid chromatography-electrospray ionization-mass spectrometry (UPLC-ESI-MS) method to examine the chemical differences between Aconitum herbs and processed products has been developed and validated. Combined with chemometrics analysis of principal component analysis (PCA) and orthogonal projection to latent structural discriminate analysis, diester-diterpenoid and monoester-type alkaloids, especially the five alkaloids which contributed to the chemical distinction between Aconitum herbs and processed products, namely mesaconitine (MA), aconitine (AC), hypaconitine (HA), benzoylmesaconitine (BMA), and benzoylhypaconitine (BHA), were picked out. Further, the five alkaloids and benzoylaconitine (BAC) have been simultaneously determined in the Xiaohuoluo pill. Chromatographic separations were achieved on a C₁₈ column and peaks were detected by mass spectrometry in positive ion mode and selected ion recording (SIR) mode. In quantitative analysis, the six alkaloids showed good regression, (r) > 0.9984, within the test ranges. The lower limit quantifications (LLOQs) for MA, AC, HA, BMA, BAC, and BHA were 1.41, 1.20, 1.92, 4.28, 1.99 and 2.02 ng·mL^-1, respectively. Recoveries ranged from 99.7% to 101.7%. The validated method was applied successfully in the analysis of the six alkaloids from different samples, in which significant variations were revealed. Results indicated that the developed assay can be used as an appropriate quality control assay for Xiaohuoluo pill and other herbal preparations containing Aconitum roots.     

A study of the analytical behaviour of selected synthetic and naturally occurring quinolines using electrospray ionisation ion trap mass spectrometry, liquid chromatography and gas chromatography and the construction of an appropriate database for quinoline characterisation

Mass spectral fragmentation of quinoline alkaloids of significance in plants has been investigated using electrospray ionisation ion trap mass spectrometry (ESI-MSⁿ) with a view to characterisation of molecules of unknown structure isolated from these natural sources. This investigation has led to the generation of an appropriate database incorporating data from ESI-MSⁿ and also from gas liquid chromatography (GLC) and liquid chromatography (HPLC) for these low molecular mass quinolines. This has been put to practical application in the identification of quinoline alkaloids in a plant extract. Thus, an acid extraction of the leaves of Choisya ternata containing such tertiary alkaloids was analysed by liquid chromatography-electrospray ionisation mass spectrometry (HPLC-ESI-MS) and the resulting behaviour of the quinolines was compared with that of the quinoline alkaloids in the database.     

Lycorine Alkaloid and Crinum americanum L. (Amaryllidaceae) Extracts Display Antifungal Activity on Clinically Relevant Candida Species

Candida species are the main fungal agents causing infectious conditions in hospital patients. The development of new drugs with antifungal potential, increased efficacy, and reduced toxicity is essential to face the challenge of fungal resistance to standard treatments. The aim of this study is to evaluate the in vitro antifungal effects of two crude extracts of Crinum americanum L., a rich alkaloid fraction and lycorine alkaloid, on the Candida species. As such, we used a disk diffusion susceptibility test, determined the minimum inhibitory concentration (MIC), and characterized the components of the extracts using Electrospray Ionization Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (ESI FT-ICR MS). The extracts were found to have antifungal activity against various Candida species. The chemical characterization of the extracts indicated the presence of alkaloids such as lycorine and crinine. The Amaryllidaceae family has a promising antifungal potential. Furthermore, it was found that the alkaloid lycorine directly contributes to the effects that were observed for the extracts and fraction of C. americanum.     

Indirect Determination of Pyrrolizidine Alkaloids by Flame Atomic Absorption Spectrometry

Abstract

This paper studies the formation and extraction of ion pairs of some alkaloids derived from pyrrolizidine. The substances studied are Nemorensine, Platyphylline, Senecionine and Seneciphylline, and the ion pairs studied and extracted are formed with Bil₄. The method consists of extracting an ion pair between the organic base and the inorganic complex, the metal is measured in the organic phase (1,2 dichloroethane) by Flame AAS. The optimal experimental conditions, pH, concentration of BiI₄ ^?, shaking time, phase ratio, number of extractions, and the range of calibration are studied for these substances. The linear range in organic phase is 0.13–1.91 mg.mL^?1. The standard deviation of the method varies between 2.4–3.2%, depending on the substance analyzed. The interferences produced by various substances are studied.     

Biosynthesis of alkaloids in Sophora alopecuroides

Summary The interconversions of the alkaloids of Sophora alopecuroides L. have been studied by feeding the plants with tritium-labelled alkaloids ([³H]sophoridine, [³H]pachycarpine, [³H]cytisine, [³H]isosophoridine, [³H]allomatrine, and [³H]N-methylcytisine). It has been established that the conformationally stable isomers of the alkaloids — isosophoridine and allomatrine — do not take part actively in the metabolism of the alkaloids. It has also been shown that the alkaloids of the sparteine group are converted into martrine alkaloids in the development of the plant. The methylation of cytisine to N-methylcytisine and the reverse transition have been shown experimentally in the plant organism.V. I. Lenin Tashkent State University. Institute of Plant Biochemistry, Academy of Sciences of the GDR, Halle. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 244–247, March–April, 1977.