Semi‐automated Separation of the Epimeric Dehydropyrrolizidine Alkaloids Lycopsamine and Intermedine: Preparation of their<i>N</i>‐oxides and NMR Comparison with Diastereoisomeric Rinderine and Echinatine

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

doi:10.1002/pca.2511

Cited by 16 publications

(19 citation statements)

References 31 publications

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“…Compound P2: 13 C‐NMR(D 2 O), δ(ppm): 15.3(q), 16.7(q), 17.0(q), 32.4(d), 35.2(t), 54.2(t), 61.0(t), 61.2(t), 69.3(d), 70.6(d), 78.7(d), 84.5(s), 124.9(d), 131.5(s), and 174.4(s). These spectra indicated that both compounds have a retronecine (7 R ) nucleus in common as a necine base and a trachelanthic or viridifloric acid moiety as a necic acid (Roeder, ; Witte et al ., ; Colegate et al ., ). In fact, hydrolysis of a mixture of P1 and P2 yielded only retronecine as a base, along with a mixture of c .…”

Section: Resultsmentioning

confidence: 97%

Production and sex-pheromonal activity of alkaloid-derived androconial compounds in the danaine butterfly,Parantica sita(Lepidoptera: Nymphalidae: Danainae)

Honda

Matsumoto

et al. 2016

Biol. J. Linn. Soc.

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Close associations of certain lepidopteran taxa with pyrrolizidine alkaloids (PAs), a typical class of plant secondary metabolites, have been well documented from the perspective of evolutionary ecology. Male danaine butterflies are thought to utilize PAs as precursors for the production of dihydropyrrolizines [e.g. danaidone (DO) and hydroxydanaidal (HD)] in their two distinct androconial organs, viz. alar scent organs (sex brands) and abdominal hairpencils. However, little is known about the quantitative profiles of these compounds in danaines, the mechanism for their formation in the androconial organs, or their biological functions, particularly in mating behaviour. The present study addressed these unanswered questions posed for males of the danaine butterfly, Parantica sita. Chemical analyses of androconial extracts revealed considerable seasonal/regional and individual variations of the amounts of DO (the major dihydropyrrolizine produced) and 7R‐HD (the 7R‐enantiomer of HD detected in this study) found in the two organs. These variations seemed to depend primarily on the age of the male and the phenological traits of PA‐containing plants available. Males were found to acquire an adequate capability to produce DO ~1 week after eclosion. DO was shown to be produced exclusively in the sex brand and subsequently physically transferred to the hairpencil through a contact behaviour between the two organs, here termed ‘perfuming behaviour’. The results of behavioural experiments with PA‐fed and PA‐unfed males that were allowed to compete for mates, combined with the positive electroantennographic (EAG) responses of the female, to both DO and 7R‐HD, led to the conclusion that either or both of these compounds can act as the sex pheromone. Oral administration of PAs to males indicated that DO can be biosynthesized from various PA precursors, while 7R‐HD, unlike in arctiid moths, is derived only from PAs with the 7R‐configuration. The putative biosynthetic pathways of DO and 7R‐HD, and the evolutionary provenance of the binate androconial system in the Danainae are also discussed.

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Section: Resultsmentioning

confidence: 97%

Production and sex-pheromonal activity of alkaloid-derived androconial compounds in the danaine butterfly,Parantica sita(Lepidoptera: Nymphalidae: Danainae)

Honda

Matsumoto

et al. 2016

Biol. J. Linn. Soc.

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“…2) (Colegate et al, 2014). The MS/MS data (Table 2) indicated it was one of the heliotridine-based epimers echinatine or rinderine (Boppré and Colegate, 2015).…”

Section: Resultsmentioning

confidence: 99%

“…acetic, angelic, iso valeric and p -coumaric acids) terminally linked to a viridifloric or trachelanthic acid esterifying C9 of the necine base, a SciFinder search indicated no previous reports of viridifloric and/or trachelanthic acid units thus linked to form a monoester dehydroPA. Differences in some 1 H and 13 C NMR chemical shifts have been associated with the stereochemistry at C13 in dehydroPAs with a single viridifloric or trachelanthic acid entity (Colegate et al, 2014). Assessment of similar resonances for compounds 10 and 11 , each with the “head-to-tail”-coupled diacid unit, provided conflicting deductions and is therefore unreliable.…”

Section: Resultsmentioning

confidence: 99%

“…Using the C18 RP HPLC mode, quantitative estimates of dehydroPA content were determined using low-range (0.45 – 7 μg/mL) and high-range (7 – 112.5 μg/mL) calibration curves generated with lycopsamine ( 1 ), purified from Symphytum officinale (Colegate et al, 2014), and normalized against the internal standard lasiocarpine ( 8 ). Therefore, quantitative estimates are reported as lycopsamine equivalents.…”

Section: Methodsmentioning

confidence: 99%

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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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“…Peak areas of identified pyrrolizidine alkaloids were determined based on reconstructed ion chromatograms from the HPLC‐ESI(+)MS and MS/MS analyses using the Synergi Hydro HPLC column method. Subsequent quantitation was against a 10‐point calibration curve (1:1 serially‐diluted from 25 to 0.05 μg/mL) generated with lycopsamine ( 1 ), purified from Symphytum officinale , and normalised against the internal standard lasiocarpine ( 6 ). Therefore, quantitative estimates are reported as lycopsamine equivalents.…”

Section: Methodsmentioning

confidence: 99%

Potentially toxic pyrrolizidine alkaloids in Eupatorium perfoliatum and three related species. Implications for herbal use as boneset

Colegate

Upton²,

Gardner

et al. 2018

Phytochemical Analysis

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Sampling issues, low and high alkaloid chemotypes of Eupatorium perfoliatum or interspecies hybridization could cause the wide variation in dehydropyrrolizidine alkaloid concentrations or the different profiles observed. Concerns associated with dehydropyrrolizidine alkaloids provide a compelling reason for preclusive caution until further research can better define the toxicity and carcinogenicity of the dehydropyrrolizidine alkaloid content of Eupatorium perfoliatum. [Correction added on 12 July 2018, after first online publication: The 'Conclusions' section in the abstract has been added.].

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Semi‐automated Separation of the Epimeric Dehydropyrrolizidine Alkaloids Lycopsamine and Intermedine: Preparation of theirN‐oxides and NMR Comparison with Diastereoisomeric Rinderine and Echinatine

Cited by 16 publications

References 31 publications

Production and sex-pheromonal activity of alkaloid-derived androconial compounds in the danaine butterfly,Parantica sita(Lepidoptera: Nymphalidae: Danainae)

Production and sex-pheromonal activity of alkaloid-derived androconial compounds in the danaine butterfly,Parantica sita(Lepidoptera: Nymphalidae: Danainae)

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

Potentially toxic pyrrolizidine alkaloids in Eupatorium perfoliatum and three related species. Implications for herbal use as boneset

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