Analysis of Pyrrolizidine Alkaloids in Queensland Honey: Using Low Temperature Chromatography to Resolve Stereoisomers and Identify Botanical Sources by UHPLC-MS/MS

Pyrrolizidine alkaloids (PAs) are a diverse group of plant secondary metabolites with known varied toxicity. Consumption of 1,2-unsaturated PAs has been linked to acute and chronic liver damage, carcinogenicity and death, in livestock and humans, making their presence in food of concern to food regulators in Australia and internationally. In this survey, honey samples sourced from markets and shops in Queensland (Australia), were analysed by high-resolution Orbitrap UHPLC-MS/MS for 30 common PAs. Relationships between the occurrence of pyrrolizidine alkaloids and the botanical origin of the honey are essential as pyrrolizidine alkaloid contamination at up to 3300 ng/g were detected. In this study, the predominant alkaloids detected were isomeric PAs, lycopsamine, indicine and intermedine, exhibiting identical MS/MS spectra, along with lesser amounts of each of their N-oxides. Crucially, chromatographic UHPLC conditions were optimised by operation at low temperature (5 °C) to resolve these key isomeric PAs. Such separation of these isomers by UHPLC, enabled the relative proportions of these PAs present in honey to be compared to alkaloid levels in suspect source plants. Overall plant pyrrolizidine alkaloid profiles were compared to those found in honey samples to help identify the most important plants responsible for honey contamination. The native Australian vines of Parsonsia spp. are proposed as a likely contributor to high levels of lycopsamine in many of the honeys surveyed. Botanical origin information such as this, gained via low temperature chromatographic resolution of isomeric PAs, will be very valuable in identifying region of origin for honey samples.

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Pyrrolizidine Alkaloid Profiles of the Senecio cineraria Group (Asteraceae)

Zeitschrift für Naturforschung C ◽

10.1515/znc-2007-7-802 ◽

2007 ◽

Vol 62 (7-8) ◽

pp. 467-472 ◽

Cited By ~ 10

Author(s):

Rosa Tundis ◽

Monica R. Loizzo ◽

Giancarlo A. Statti ◽

Nicodemo G. Passalacqua ◽

Lorenzo Peruzzi ◽

...

Keyword(s):

Pyrrolizidine Alkaloids ◽

Pyrrolizidine Alkaloid ◽

Alkaloid Profiles

Alkaloid profiles of five Senecio species (Asteraceae), including S. ambiguus subsp. ambiguus, S. ambiguus subsp. nebrodensis, S. gibbosus subsp. bicolor, S. gibbosus subsp. gibbosus, and S. gibbosus subsp. cineraria, were studied. Eleven pyrrolizidine alkaloids were identified and their content was evaluated by GLC-MS and GLC analysis. Otosenine and florosenine were found to be the major alkaloids in all studied species. It is interesting that only S. ambiguus subsp. nebrodensis was characterized by a high content of the alkaloids jacobine, jacoline, jaconine, and jacozine

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Pyrrolizidine Alkaloid Profiles of Some Senecio Species from Egypt

Zeitschrift für Naturforschung C ◽

10.1515/znc-2002-5-604 ◽

2002 ◽

Vol 57 (5-6) ◽

pp. 429-433 ◽

Cited By ~ 9

Author(s):

Assem El-Shazly

Keyword(s):

Mass Spectrometry ◽

Pyrrolizidine Alkaloids ◽

Pyrrolizidine Alkaloid ◽

Plant Organs ◽

Capillary Glc ◽

Cultivated Species ◽

Alkaloid Profiles ◽

C Nmr

Alkaloid profiles of two Egyptian Senecio species (Senecio aegyptius var. discoideus and S. desfontainei) in addition to a cultivated species (S. cineraria) were studied using capillary GLC and GLC-mass spectrometry with respect to pyrrolizidine alkaloids (PAs). Four alkaloids were identified in S. aegyptius var. discoideus, 8 in S. desfontainei and 13 in S. cineraria. Some of these alkaloids have not been reported from these plants. The alkaloidal pattern of different plant organs (flowers, leaves, stem, root) were also investigated. Senecionine has been found to be a one of the major alkaloid in all studied species, it was isolated and its structure was elucidated by 1H- and 13C-NMR.

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Analysis and chemotaxonomic significance of pyrrolizidine alkaloids from two Boraginaceae species growing in Algeria

Zeitschrift für Naturforschung C ◽

10.1515/znc-2020-0225 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

Houari Benamar ◽

Abderrazak Marouf ◽

Malika Bennaceur

Keyword(s):

Mass Spectrometry ◽

Pyrrolizidine Alkaloids ◽

Pyrrolizidine Alkaloid ◽

Fragment Ions ◽

The Family ◽

Kováts Indices ◽

Chemotaxonomic Study ◽

Botanical Classification ◽

Alkaloid Profiles

Abstract In the current study the pyrrolizidine alkaloid profiles of the species Echium sabulicola ssp. decipiens (Pomel) Klotz and Solenanthus lanatus DC were studied in various extracts. In addition, a chemotaxonomic study within the genus and the family was carried out. The analysis was carried out by using gas chromatography coupled to mass spectrometry and by comparing the Kovats Indices and molecular and fragment ions with literature data. Twenty-three alkaloids were tentatively identified. The results showed the presence of already reported compounds as well as previously unreported ones leading both to a confirmation of the botanical classification of the two studied species and to a brand new path in the chemotaxonomy of Boraginaceae family. The presence of some pyrrolizidine alkaloids sets limits for the usage of these plants for medicinal purposes. The identified compounds confirm the botanical classification of the studied species as members of the Boraginaceae family and their presence advices against their use in the ethnopharmacological field.

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Pyrrolizidine Alkaloid-Induced Hepatotoxicity Associated with the Formation of Reactive Metabolite-Derived Pyrrole–Protein Adducts

Toxins ◽

10.3390/toxins13100723 ◽

2021 ◽

Vol 13 (10) ◽

pp. 723

Author(s):

Jiang Ma ◽

Mi Li ◽

Na Li ◽

Wood Yee Chan ◽

Ge Lin

Keyword(s):

Natural Products ◽

Pyrrolizidine Alkaloids ◽

Pyrrolizidine Alkaloid ◽

Protein Adducts ◽

Dependent Manner ◽

Histological Changes ◽

Histological Results ◽

Dose Dependent ◽

Different Doses ◽

Alt Activity

Pyrrolizidine alkaloids (PAs) with 1,2-unsaturated necine base are hepatotoxic phytotoxins. Acute PA intoxication is initiated by the formation of adducts between PA-derived reactive pyrrolic metabolites with cellular proteins. The present study aimed to investigate the correlation between the formation of hepatic pyrrole–protein adducts and occurrence of PA-induced liver injury (PA-ILI), and to further explore the use of such adducts for rapidly screening the hepatotoxic potency of natural products which contain PAs. Aqueous extracts of Crotalaria sessiliflora (containing one PA: monocrotaline) and Gynura japonica (containing two PAs: senecionine and seneciphylline) were orally administered to rats at different doses for 24 h to investigate PA-ILI. Serum alanine aminotransferase (ALT) activity, hepatic glutathione (GSH) level, and liver histological changes of the treated rats were evaluated to assess the severity of PA-ILI. The levels of pyrrole–protein adducts formed in the rats’ livers were determined by a well-established spectrophotometric method. The biological and histological results showed a dose-dependent hepatotoxicity with significantly different toxic severity among groups of rats treated with herbal extracts containing different PAs. Both serum ALT activity and the amount of hepatic pyrrole–protein adducts increased in a dose-dependent manner. Moreover, the elevation of ALT activity correlated well with the formation of hepatic pyrrole–protein adducts, regardless of the structures of different PAs. The findings revealed that the formation of hepatic pyrrole–protein adducts—which directly correlated with the elevation of serum ALT activity—was a common insult leading to PA-ILI, suggesting a potential for using pyrrole–protein adducts to screen hepatotoxicity and rank PA-containing natural products, which generally contain multiple PAs with different structures.

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Characterization and Lifetime Dietary Risk Assessment of Eighteen Pyrrolizidine Alkaloids and Pyrrolizidine Alkaloid N-Oxides in New Zealand Honey

Toxins ◽

10.3390/toxins13120843 ◽

2021 ◽

Vol 13 (12) ◽

pp. 843

Author(s):

Andrew J. Pearson ◽

Jeane E. F. Nicolas ◽

Jane E. Lancaster ◽

C. Wymond Symes

Keyword(s):

New Zealand ◽

Pyrrolizidine Alkaloids ◽

Pyrrolizidine Alkaloid ◽

Food Additives ◽

Dietary Exposure ◽

World Health ◽

Exposure Model ◽

Average Lifetime ◽

Expert Committee ◽

Dietary Risk

Pyrrolizidine alkaloids (PAs) are a large group of botanical toxins of concern, as they are considered genotoxic carcinogens, with long-term dietary exposure presenting an elevated risk of liver cancer. PAs can contaminate honey through honeybees visiting the flowers of PA-containing plant species. A program of monitoring New Zealand honey has been undertaken over several years to build a comprehensive dataset on the concentration, regional and seasonal distribution, and botanical origin of 18 PAs and PA N-oxides. A bespoke probabilistic exposure model has then been used to assess the averaged lifetime dietary risk to honey consumers, with exposures at each percentile of the model characterized for risk using a margin of exposure from the Joint World Health Organization and United Nations Food and Agriculture Organization Expert Committee on Food Additives (JECFA) Benchmark Dose. Survey findings identify the typical PA types for New Zealand honey as lycopsamine, echimidine, retrorsine and senecionine. Regional and seasonal variation is evident in the types and levels of total PAs, linked to the ranges and flowering times of certain plants. Over a lifetime basis, the average exposure an individual will receive through honey consumption is considered within tolerable levels, although there are uncertainties over high and brand-loyal consumers, and other dietary contributors. An average lifetime risk to the general population from PAs in honey is not expected. However, given the uncertainties in the assessment, risk management approaches to limit or reduce exposures through honey are still of value.

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Quantitative Removal of Pyrrolizidine Alkaloids from Essential Oils by the Hydrodistillation Step in Their Manufacturing Process

Planta Medica ◽

10.1055/a-1534-6928 ◽

2021 ◽

Author(s):

David S. Giera ◽

Michael Preisitsch ◽

Hugues Brevard ◽

Jörn Nemetz

Keyword(s):

Essential Oils ◽

Manufacturing Process ◽

Pyrrolizidine Alkaloids ◽

Pyrrolizidine Alkaloid ◽

Medicinal Products ◽

Herbal Medicinal Products ◽

Naturally Occurring ◽

Herbal Medicinal ◽

Set Up ◽

Theoretical Considerations

AbstractPyrrolizidine alkaloids are naturally occurring toxins produced by certain weeds that can, if accidentally co-harvested, contaminate plant-based food, feed, and herbal medicinal products. Focusing on herbal medicinal products, the presence of pyrrolizidine alkaloids is restricted by regulatory prescribed thresholds to assure patient safety. Among the multitude of different herbal active substances utilized in herbal medicinal products, the class of pharmaceutically effective essential oils is considered to exhibit a negligible contribution to pyrrolizidine alkaloid contamination. Within the present investigation, this hypothesis should be scientifically scrutinized. For this purpose, an experimental set-up was chosen that reproduces the typical manufacturing step of hydrodistillation. Essential oils of eucalyptus and lemon were selected exemplarily and spiked with 3 representative pyrrolizidine alkaloids (retrorsine, retrorsine-N-oxide, and lycopsamine), whereupon hydrodistillation was performed. Analysis of the resulting distillates by LC-MS/MS proved that artificially added pyrrolizidine alkaloids were removed completely. Moreover, quantitative pyrrolizidine alkaloid recovery in the aqueous phases was observed. Hence, it was experimentally confirmed that herbal medicinal products employing hydrodistilled essential oils of pharmaceutical quality are intrinsically free of pyrrolizidine alkaloids due to the particularities of their manufacturing process. Furthermore, it can be concluded from theoretical considerations that essential oils produced by cold pressing have a negligible risk of carrying pyrrolizidine alkaloid contamination. Our findings provide a strong indication that the requirement for analytical pyrrolizidine alkaloid testing of essential oils for pharmaceutical use should be fundamentally reconsidered.

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Further Evidence on the Intramolecular Lactonization in Rat Liver Microsomal Metabolism of 12-O-acetylated Retronecine-type Pyrrolizidine Alkaloids

Natural Product Communications ◽

10.1177/1934578x1300801111 ◽

2013 ◽

Vol 8 (11) ◽

pp. 1934578X1300801 ◽

Cited By ~ 1

Author(s):

Jun Tang ◽

Zhengtao Wang ◽

Teruaki Akao ◽

Masao Hattori

Keyword(s):

Physical Properties ◽

Spectral Data ◽

Rat Liver ◽

Pyrrolizidine Alkaloids ◽

Pyrrolizidine Alkaloid ◽

Liver Microsomes ◽

Rat Liver Microsomes ◽

Microsomal Metabolism ◽

Chromatographic Methods ◽

Transformation Pathway

We have previously found evidence of intramolecular lactonization in rat liver microsomal metabolism of isoline, a 12- O-acetylated pyrrolizidine alkaloid. In this study, the metabolism of another 12- O-acetylated pyrrolizidine alkaloid, acetylduciformine, by the proposed transformation pathway was investigated under the same incubation conditions. Two deacetylated metabolites from acetylduciformine were isolated and purified by chromatographic methods, and further characterized based on their physical properties and spectral data. One metabolite (lankongensisine A) was the lactone of another one (duciformine). Both compounds were first obtained as hydrolyzed metabolites from acetylduciformine by rat liver microsomes. More importantly, the present study provided further evidence for the intramolecular lactonization in the microsomal metabolism of 12- O-acetylated retronecine-type PAs.

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Development of a Selective Adsorbing Material for Binding of Pyrrolizidine Alkaloids in Herbal Extracts, Based on Molecular Group Imprinting

Planta Medica ◽

10.1055/a-0961-2658 ◽

2019 ◽

Vol 85 (13) ◽

pp. 1107-1113 ◽

Cited By ~ 1

Author(s):

Thomas Kopp ◽

Mona Abdel-Tawab ◽

Martin Khoeiklang ◽

Boris Mizaikoff

Keyword(s):

Pyrrolizidine Alkaloids ◽

Binding Capacity ◽

Specific Binding ◽

Pyrrolizidine Alkaloid ◽

Daily Intake ◽

Chelidonium Majus ◽

Molecular Imprinted Polymers ◽

Binding Characteristics ◽

Molecular Group ◽

Plant Constituents

AbstractPyrrolizidine alkaloids are secondary plant constituents that became a subject of public concern because of their hepatotoxic, pneumotoxic, genotoxic, and cytotoxic effects. Due to disregardful harvesting and/or contamination with pyrrolizidine alkaloid-containing plants, there is a high risk of ingesting these substances with plant extracts or natural products. The limit for the daily intake was set to 0.007 µg/kg body weight. If contained in an extract, cleanup methods may help to minimize the pyrrolizidine alkaloid concentration. For this purpose, a material for depleting pyrrolizidine alkaloids in herbal preparations was developed based on the approach of molecular imprinting using monocrotaline. Molecular imprinted polymers are substances with specific binding characteristics, depending on the template used for imprinting. By means of group imprinting, only one molecule is used for creating selective cavities for many molecular pyrrolizidine alkaloid variations. Design of Experiment was used for the development using a 25 screening plan resulting in 64 polymers (32 MIPs/32 NIPs). Rebinding trials revealed that the developed material can compete with common cation exchangers and is more suitable for depleting pyrrolizidine alkaloids than C18- material. Matrix trials using an extract from Chelidonium majus show that there is sufficient binding capacity for pyrrolizidine alkaloids (80%), but the material is lacking in selectivity towards pyrrolizidine alkaloids in the presence of other alkaloids with similar functional groups such as berberine, chelidonine, and coptisine. Beyond this interaction, the selectivity could be proven for other structurally different compounds on the example of chelidonic acid.

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Model systems for detecting the hepatic toxicity of pyrrolizidine alkaloids and pyrrolizidine alkaloid N-oxides

Toxicology and Applied Pharmacology ◽

10.1016/0041-008x(89)90276-7 ◽

1989 ◽

Vol 101 (2) ◽

pp. 271-284 ◽

Cited By ~ 2

Author(s):

David J. Moore ◽

Kenneth P. Batts ◽

Leon L. Zalkow ◽

G.Thomas Fortune ◽

Garth Powis

Keyword(s):

Pyrrolizidine Alkaloids ◽

Pyrrolizidine Alkaloid ◽

Model Systems ◽

Hepatic Toxicity

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Time-Course of Pyrrolizidine Alkaloid Processing in the Alkaloid Exploiting Arctiid Moth, Creatonotos transiens

Zeitschrift für Naturforschung C ◽

10.1515/znc-1990-7-822 ◽

1990 ◽

Vol 45 (7-8) ◽

pp. 881-894 ◽

Cited By ~ 32

Author(s):

Eva von Nickisch-Rosenegk ◽

Dietrich Schneider ◽

Michael Wink

Keyword(s):

Laboratory Experiments ◽

Time Course ◽

Pyrrolizidine Alkaloids ◽

Pyrrolizidine Alkaloid ◽

Hydroxyl Group ◽

Short Term ◽

Arctiid Moth ◽

Total Alkaloids ◽

Creatonotos Transiens

Abstract The processing of dietary pyrrolizidine alkaloids by larvae and adults of the arctiid moth Creatonotos transiens was studied in time-course experiments: In larvae, pyrrolizidine alkaloid uptake is quickly followed by the transformation of the alkaloids into their N-oxides. Further- more, if 7 S-heliotrine is applied, a stereochemical inversion of the hydroxyl group at C 7 to 7 R-heliotrine can be observed within 48 h of feeding. The rate of this biotransformation is substantially higher in males which use the 7 R-form later as a precursor for the biosynthesis of 7 R-hydroxydanaidal, a pheromone. The resorbed pyrrolizidine alkaloids are deposited in the integument within 48 h, where they remain stored during the larval, pupal and partly also the imaginal stages. Virtually no alkaloids are lost during ecdysis. Some pyrrolizidine alkaloids can be recovered from the meconium which is released at eclosion by the imagines especially when disturbed. In the adults pyrrolizidine alkaloids are processed in different ways by the two sexes: In females, about 50-80% of total alkaloids are transferred from the integument to the ovaries and the eggs within 2 - 3 days after eclosion. If females mate with alkaloid-rich males they additionally receive with the spermatophore up to 290 jig pyrrolizidine alkaloid, which are further translocated to the eggs. A biparental endowment of eggs with acquired defence alkaloids is thus achieved. In males, 30-50% of pyrrolizidine alkaloids remain in the integu- ment; about 10 - 30% are transferred to the scent organ, the corema, where they are converted into 7 R-hydroxydanaidal. Another part (about 40%) is passed to the spermatophore. In the laboratory experiments, the sizes of the coremata and their respective 7 R-hydroxydanaidal contents are strongly dependent on the availability of dietary pyrrolizidine alkaloids during L6 and especially L7 stages. In the L7 stage even short-term feeding (4-6 h) on Senecio jaco- haea is sufficient to induce large coremata.

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