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.     

An experimental design approach to obtain canthinone alkaloid-enriched extracts from Simaba aff. paraensis

The species of the genus Simaba (Simaroubaceae) are found in almost all Brazil and they are used by local population for the treatment of ulcers and malaria. The genus is characterized by the presence of quassinoids and canthinone alkaloids. There is a great interest in canthinones due to important biological activities associated with this class of alkaloids. In this study, methods were developed for obtaining enriched fractions of canthinone alkaloids from Simaba aff. paraensis using experimental factorial design analyzed by gas chromatography. Three alkaloids were detected: canthin-6-one, 4,5-dimethoxycanthin-6-one and the major 9-methoxycanthin-6-one. Within the experimental domain, factorial designs 2² helped establish the minimum amount of solvent and minimum time necessary to obtain extracts enriched in canthinone alkaloids from S. aff. paraensis barks by two extraction methods. These results represent a reduction in costs for obtaining canthinone alkaloids described for the first time in S. aff. paraensis.     

Alkaloids of the Genus Datura: Review of a Rich Resource for Natural Product Discovery

The genus Datura (Solanaceae) contains nine species of medicinal plants that have held both curative utility and cultural significance throughout history. This genus’ particular bioactivity results from the enormous diversity of alkaloids it contains, making it a valuable study organism for many disciplines. Although Datura contains mostly tropane alkaloids (such as hyoscyamine and scopolamine), indole, beta-carboline, and pyrrolidine alkaloids have also been identified. The tools available to explore specialized metabolism in plants have undergone remarkable advances over the past couple of decades and provide renewed opportunities for discoveries of new compounds and the genetic basis for their biosynthesis. This review provides a comprehensive overview of studies on the alkaloids of Datura that focuses on three questions: How do we find and identify alkaloids? Where do alkaloids come from? What factors affect their presence and abundance? We also address pitfalls and relevant questions applicable to natural products and metabolomics researchers. With both careful perspectives and new advances in instrumentation, the pace of alkaloid discovery—from not just Datura—has the potential to accelerate dramatically in the near future.     

Synthesis and reactivity of pelletierine-derived building blocks and pelletierine analogs

Lycopodium alkaloids are unique (and often impressive in terms of structures) polycyclic alkaloids that attract great interest from a biological point of view and that also provide ideal targets for total synthesis. Propylpiperidine units closely related to pelletierine are involved in the biosynthesis of these alkaloids. Therefore, stable pelletierine-like compounds, especially a (R)-phenylglycinol-based oxazolopiperidine analog, were prepared and their reactivity investigated. The compounds described in this work expand the tool-box of small building blocks in the piperidine series and pelletierine analogs and could be suitable for the synthesis of Lycopodium alkaloids following biosynthetically inspired strategies.     

Alkaloids ofLiriodendron tulipifera

The alkaloids of the tulip treeLiriodendron tulipifera L., family Magnoliaceae, are considered. More then 20 alkaloids have been isolated during different vegetation periods from various organs of the plant growing in Uzbekistan, and these have been assigned to the aporphine alkaloids and their dehydro, oxo, and 7-hydroxy derivatives; only two alkaloids proved to be derivatives of proaphorphine and of tetrahydroberberine. On the basis of the results of a comparative study of the NMR spectra of aporphines unsubstituted in ring D and some chemical transformations, the structure and configuration of the (R)-3-hydroxy-1,2-dimethoxyaporphine have been proposed for the new alkaloid lirinine. The absolute configurations, possible biogenetic interconnections, and mutual transitions of the alkaloids ofL. tylipifera that are derivatives of aporphine, oxoaporphine, and dehydroaporphine are discussed. A summery table is given which includes 41 alkaloids found in this plant.     

Studies on the aconitine-type alkaloids in the roots of Aconitum Carmichaeli Debx. by HPLC/ESIMS/MS

Studies of aconitine-type alkaloids in the Chinese herb Aconitum Carmichaeli were performed by HPLC/ESIMS/MSⁿ and FTICR/ESIMS in positive ion mode. The characteristic fragmentation pathways in the MSⁿ spectra were summarized based on previously published research literature and further study. According to the fragmentation pathways of mass spectrometry, results from the analysis of standard compounds and reports from literature, 111 compounds were identified or deduced in a total of 117 found compounds in A. Carmichaeli. In the 11 monoester-diterpenoid alkaloids (MDA), 10 diesterditerpenoid alkaloids (DDA) and 81 lipo-alkaloids, the novel alkaloids including 1 MDA, 2 DDA and 48 lipo-alkaloids were detected. In addition, 1 DDA, 7 lipo-alkaloids and 2 alkaloids with small molecular weights that possess C19-norditerpenoid skeleton were reported in A. Carmichaeli for the first time.     

Antifungal Activity of New Diterpenoid Alkaloids Isolated by Different Chromatographic Methods from Delphinium peregrinum L. var. eriocarpum Boiss

This paper aimed to investigate the potential antifungal influences of new alkaloids from Delphinium peregrinum L. var. eriocarpum Boiss. New Diterpenoid alkaloids Delcarpum (1), Hydrodavisine (4) and known alkaloids Peregrine (2), Delphitisine (3) were isolated by different chromatographic methods from the aerial parts of D. Peregrinum eriocarpum Boiss, which grows in Syria. The structures of alkaloids were proposed based on 1D NMR spectroscopy ¹H-NMR, ¹³C-NMR, DEPT-135, DEPT-90, 2D NMR spectroscopy DQF-COSY, HMQC, EI-Ms mass spectrum, and IR spectroscopic measurements. The antifungal activity of the isolated alkaloids was evaluated against different dermatophyte fungal isolates compared with fluconazole. In the case of Peregrine (2) the minimum inhibitory concentrations(MICs) recorded 128–256, 32–64, and 32 for Epidermophyton floccosum, Microsporum canis, and Trichophyton rubrum, respectively, compared to 32–64, 16, and 32 μg/mL in the case of fluconazole, respectively. The MICs recorded on application of the four alkaloids mixture were 64, 32, and 16 in the case of E. floccosum, M. canis, and T. rubrum, respectively, which were significantly lower than that measured for each of the individual alkaloid and were compatible for fluconazole. In conclusion, MICs of the tested alkaloids showed a variable potential effect on the investigated fungal isolates. Peregrine (2) was the most effective alkaloid, however, the application of the mixture of alkaloids induced significant synergistic activity that was more pronounced than the application of individual ones.     

Mamanine and pohakuline,two unprecedented quinolizidine alkaloids from sophorachrysophylla

From the bark of the endemic Hawaiian tree Sophora chrysophylla Seem. we have isolated two unprecedented quainolizidine alkaloids, mamanine (4) and pohakuline (5). Both bases are 1-hydroxymethylenequinolizidines which are linked at C-3 to α-pyridone or α-piperidone moieties. The alkaloids may be intermediates in a heretofore unknown biogenetic pathway of Sophora alkaloids.     

Athrotaxis alkaloids. Part II. Alkaloids of a. selaginoides and a. laxifolia

The taxodeaceous plant A. Selaginoides contains six known homoerythrina-type alkaloids and selaginoidine, which has a furan ring replacing the benzene ring of the latter type. Selaginoidine and five of the six above-mentioned alkaloids also occur in A. laxifolia.     

Ungernia alkaloids

The review is devoted to the study of the alkaloids of plants of the genusUngernia (Amaryllidaceae). It gives their characteristic reactions and information on the determination of their structures and stereochemistry and on the dynamics of the accumulation of alkaloids in the plants of the genusUngernia. A dependence of the physiological activity of the alkaloids on their structure is shown.     

Enzymatic biosynthesis of benzylisoquinoline alkaloid glycosides via promiscuous glycosyltransferases from Carthamus tinctorius

Three new GTs (UGT84A33, UGT71AE1 and UGT90A14) from Carthamus tinctorius exhibited robust catalytic promiscuity to benzylisoquinoline alkaloids, and were used as enzymatic tools for the synthesis of diverse benzylisoquinoline alkaloid glycosides.     

Pyrrolizidine-Derived Alkaloids: Highly Toxic Components in the Seeds of Crotalaria cleomifolia Used in Popular Beverages in Madagascar

Seeds of Crotalaria cleomifolia (Fabaceae) are consumed in Madagascar in preparation of popular beverages. The investigation of extracts from the seeds of this species revealed the presence of high amounts of alkaloids from which two pyrrolizidine-derived alkaloids were isolated. One of them was fully characterized by spectroscopic and spectrometric methods, which was found to be usaramine. Owing to the high toxicity of these alkaloids, issuing a strong warning among populations consuming the seeds of Crotalaria cleomifolia must be considered.     

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.     

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.     

Mersinaline and mersirachine, novel quinolinic alkaloids of the mersinine group from Kopsia

Two quinolinic alkaloids belonging to the novel mersinine subclass were isolated from Kopsia singapurensis. The structures of these alkaloids were established by spectroscopic methods and possible biogenetic relationships between these and the mersinine alkaloids are presented.     

Tacamine-type alkaloids from Tabernaemontana bovina together with their configuration determination

Eleven undescribed tacamine type alkaloids, named tabercamines A–K were isolated from leaves of Tabernaemontana bovina, together with six known alkaloids. The planar structure of the undescribed alkaloids were determined by comprehensive spectroscopic data analysis. Their absolute configuration were established based on the combination of the electronic circular dichroism and single X-ray crystal diffraction analysis. The NMR rules (in acetone-d₆) of identifying of the stereo-configuration at C-20/16 was established.     

Alkaloids Analysis of Habranthus cardenasianus (Amaryllidaceae), Anti-Cholinesterase Activity and Biomass Production by Propagation Strategies

Plants in the Amaryllidaceae family synthesize a diversity of bioactive alkaloids. Some of these plant species are not abundant and have a low natural multiplication rate. The aims of this work were the alkaloids analysis of a Habranthus cardenasianus bulbs extract, the evaluation of its inhibitory activity against cholinesterases, and to test several propagation strategies for biomass production. Eleven compounds were characterized by GC-MS in the alkaloid extract, which showed a relatively high proportion of tazettine. The known alkaloids tazettine, haemanthamine, and the epimer mixture haemanthidine/6-epi-haemanthidine were isolated and identified by spectroscopic methods. Inhibitory cholinesterases activity was not detected. Three forms of propagation were performed: bulb propagation from seed, cut-induced bulb division, and micropropagated bulbs. Finally, different imbibition and post-collection times were evaluated in seed germination assays. The best propagation method was cut-induced bulb division with longitudinal cuts into quarters (T1) while the best conditions for seed germination were 0-day of post-collection and two days of imbibition. The alkaloids analyses of the H. cardenasianus bulbs showed that they are a source of anti-tumoral alkaloids, especially pretazettine (tazettine) and T1 is a sustainable strategy for its propagation and domestication to produce bioactive alkaloids.     

Six new indole alkaloids from Gelsemium sempervirens Ait. f.

One new yohimbane and five new sarpagine-type indole alkaloids were isolated from the radix of Gelsemium sempervirens Ait. f., and their structures were determined by spectroscopic analysis, chemical conversion or total synthesis. It was found that 2-acyl sarpagine-type alkaloids possessing an N_b-methyl group take a keto-amino structure or a transannular form in solution depending on the solvent.     

Application of non-ionic surfactant in the microwave-assisted extraction of alkaloids from Rhizoma Coptidis

The feasibility of employing non-ionic surfactant oligoethylene glycol monoalkyl ether (Genapol X-080) as an alternative and effective solvent for the microwave-assisted extraction of alkaloids from Rhizoma Coptidis was demonstrated. When compared with commonly used solvents, 5% Genapol X-080 enhanced the extraction efficiency. Under optimal conditions, i.e. 5% acidified Genapol X-080 (v/v), microwave-assisted extraction for 10 min at 100 °C, the extraction recovery of alkaloids reached 92.8% in a one-step extraction. The efficiency of cloud-point preconcentration of three alkaloids was in the range 93.6-94.7% with relative standard deviation lower than 3.3% by the proposed procedure. Furthermore, the combination of microwave-assisted extraction and cloud-point extraction was shown to be a green, rapid and effective approach for alkaloids preconcentration of Rhizoma Coptidis samples.     

Alcaloïdes indoliques—CII : Deux nouveaux types d'alcaloïdes indoliques l'ibophyllidine,dérivé du nor-21(+)pandolane et l'iboxyphylline dérivé de l'abeo-21(20→19) (+)pandolane,retirés des feuilles de tabernanthe iboga baillon et de t. subsessilis stapf

Two alkaloids from Iboga, ibophyllidine and iboxyphylline, were isolated from the leaves of T. iboga and T. subsessilis. Chemical and physical data led to their structural assignments. The structure of iboxyphylline was confirmed by X-ray analysis. These alkaloids belong to a new Iboga sub-group.