Dehydropyrrolizidine Alkaloids in Two <i>Cryptantha</i> Species: Including Two New Open Chain Diesters One of Which is Amphoteric

Colegate, Steven M.; Gardner, Dale R.; Davis, T. Zane; Betz, Joseph M.; Panter, Kip E.

doi:10.1002/pca.2400

Cited by 9 publications

(14 citation statements)

References 23 publications

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“…Accordingly, the proton resonances noted for echivulgarine were all consistent with the trends noted 30 for a syn relationship between H-7 and H-8, although the signals for H 2 -6 to H-8 resonate approximately 0.2 ppm downfield of those reported previously. 30 Such a syn relationship would result in the 7R*, 8R* relative configuration as previously assumed. This proposed relative configuration was supported by observation of multiple through-space interactions via a two-dimensional NOESY experiment (Figure 3).…”

Section: Journal Of Agricultural and Food Chemistrymentioning

confidence: 88%

Structure of Echivulgarine, a Pyrrolizidine Alkaloid Isolated from the Pollen ofEchium vulgare

Cairns¹,

Hashmı

Singh

et al. 2015

J. Agric. Food Chem.

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1,2-Dehydropyrrolizidine alkaloids are common toxic metabolites isolated from plants within the Boraginaceae, in particular from the genera Heliotropium and Echium. Previous studies have deduced the structures of these often potent bioactives based upon mass spectrometric evidence, but these identifications have not established conclusive connectivity and configurational data. Herein, we describe the isolation and full structural characterization of echivulgarine, occurring in the pollen of Echium vulgare and correct the structure previously ascribed to the compound, using a comprehensive combination of both experimental and calculated nuclear magnetic resonance and electronic circular dichroism spectroscopic data.

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Section: Journal Of Agricultural and Food Chemistrymentioning

confidence: 88%

Structure of Echivulgarine, a Pyrrolizidine Alkaloid Isolated from the Pollen ofEchium vulgare

Cairns¹,

Hashmı

Singh

et al. 2015

J. Agric. Food Chem.

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“…Since it has been previously shown that 2D NOESY interactions between H7 and H8 are an unreliable indicator of the relative configuration of these protons in some dehydroPAs (Colegate et al, 2013), an attempt was made to demonstrate the heliotridine or retronecine configuration of alkaloid 10 using a 1D GOESY NMR experiment. However, using heliotrine and lycopsamine as model heliotridine and retronecine monoesters respectively, a GOESY interaction was observed for both.…”

Section: Resultsmentioning

confidence: 99%

“…(2008) and applied to the necine base determination of the open chain diester dehydroPA cryptanthine (Colegate et al, 2013), LiAlH 4 solution (200 μL) was added to each sample vial and left to stand at room temperature for 2 h. Dichloromethane (1 mL) was added to each vial, causing very slight effervescence with the LiAlH 4 mixtures. Cautiously, 1 drop at a time, an aqueous solution of sodium hydroxide (10% w/v) was added resulting in vigorous effervescence and formation of a glutinous white solid.…”

Section: Methodsmentioning

confidence: 99%

Pro-toxic dehydropyrrolizidine alkaloids in the traditional Andean herbal medicine “asmachilca”

Colegate

Boppré

Monzon

et al. 2015

Journal of Ethnopharmacology

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Ethnopharmacological relevance Asmachilca is a Peruvian medicinal herb preparation ostensibly derived from Eupatorium gayanum Wedd. = Aristeguietia gayana (Wedd.) R.M. King & H. Rob. (Asteraceae: Eupatorieae). Decoctions of the plant have a reported bronchodilation effect that is purported to be useful in the treatment of respiratory allergies, common cold and bronchial asthma. However, its attractiveness to pyrrolizidine alkaloid-pharmacophagous insects indicated a potential for toxicity for human consumers. Aim of the study To determine if commercial asmachilca samples, including fully processed herbal teas, contain potentially toxic 1,2-dehydropyrrolizidine alkaloids. Materials and methods Two brands of “Asmachilca” herbal tea bags and four other commercial samples of botanical materials for preparing asmachilca medicine were extracted and analyzed using HPLC-esi(+)MS and MS/MS for the characteristic retention times and mass spectra of known dehydropyrrolizidine alkaloids. Other suspected dehydropyrrolizidine alkaloids were tentatively identified based on MS/MS profiles and high resolution molecular weight determinations. Further structure elucidation of isolated alkaloids was based on 1D and 2D NMR spectroscopy. Results Asmachilca attracted many species of moths which are known to pharmacophagously gather dehydropyrrolizidine alkaloids. Analysis of 5 of the asmachilca samples revealed the major presence of the dehydropyrrolizidine alkaloid monoesters rinderine and supinine, and their N-oxides. The 6th sample was very similar but did not contain supinine or its N-oxide. Small quantities of other dehydropyrrolizidine alkaloid monoesters, including echinatine and intermedine, were also detected. In addition, two major metabolites, previously undescribed, were isolated and identified as dehydropyrrolizidine alkaloid monoesters with two “head-to-tail” linked viridifloric and/or trachelanthic acids. Estimates of total pyrrolizidine alkaloid and N-oxide content in the botanical components of asmachilca varied from 0.4 – 0.9% (w/dw, dry weight) based on equivalents of lycopsamine. The mean pyrrolizidine alkaloid content of a hot water infusion of a commercial asmachilca herbal tea bag was 2.2 ± 0.5 mg lycopsamine equivalents. Morphological and chemical evidence showed that asmachilca is prepared from different plant species. Conclusions All asmachilca samples and the herbal tea infusions contained toxicologically-relevant concentrations of pro-toxic 1,2-dehydropyrrolizidine alkaloid esters and, therefore, present a risk to the health of humans. This raises questions concerning the ongoing unrestricted availability of such products on the Peruvian and international market. In addition to medical surveys of consumers of asmachilca, in the context of chronic disease potentially associated with ingestion of the dehydropyrrolizidine alkaloids, the botanical origins of asmachilca preparations require detailed elucidation.

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“…MCT concentration of the seeds was determined by HPLC-ESIMS analysis of methanolic extracts using authentic MCT (crotaline; Sigma-Aldrich, USA) as the calibration standard (COLEGATE et al, 2012a(COLEGATE et al, , 2012b.…”

Section: Methodsmentioning

confidence: 99%

Duration of an induced resistance of sheep to acute poisoning by Crotalaria retusa seeds

et al. 2014

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Dehydropyrrolizidine Alkaloids in Two Cryptantha Species: Including Two New Open Chain Diesters One of Which is Amphoteric

Cited by 9 publications

References 23 publications

Structure of Echivulgarine, a Pyrrolizidine Alkaloid Isolated from the Pollen ofEchium vulgare

Structure of Echivulgarine, a Pyrrolizidine Alkaloid Isolated from the Pollen ofEchium vulgare

Pro-toxic dehydropyrrolizidine alkaloids in the traditional Andean herbal medicine “asmachilca”

Duration of an induced resistance of sheep to acute poisoning by Crotalaria retusa seeds

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