UPLC-MS/MS method for determination of selected pyrrolizidine alkaloids in feed

Quantitative Analysis of Pyrrolizidine Alkaloids in Food Matrices and Plant-Derived Samples Using UHPLC-MS/MS

Pyrrolizidine alkaloids (PAs) are a class of nitrogen-containing basic organic compounds that are frequently detected in foods and herbal medicines. Owing to their potential hepatotoxic, genotoxic, and carcinogenic properties, PAs have become a significant focus for monitoring global food safety. In this study, an ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method was developed for the detection and analysis of three foods (tea, honey, and milk) susceptible to PA contamination. This optimized method effectively separated and detected three types of PAs, namely, three pairs of isomers and two pairs of chiral compounds. The limits of detection (LODs) and limits of quantification (LOQs) were determined to be 0.015-0.75 and 0.05-2.5 µg/kg, respectively, with the relative standard deviations (RSDs) of both the interday and intraday precisions remaining below 15%. The average PA recoveries from the honey, milk, and tea matrices fell within the ranges of 64.5-103.4, 65.2-112.2, and 67.6-107.6%, respectively. This method was also applied to 77 samples collected from 33 prefecture-level cities across 16 provinces and included 40 tea, 6 milk, 8 honey, 14 spice, and 9 herbal medicine samples. At least one PA was detected in twenty-three of the samples, with herbal medicines exhibiting the highest total PA content. The obtained results indicate that the developed method demonstrated good repeatability and stability in the detection and quantitative analyses of PAs in food- and plant-derived samples. This method is therefore expected to provide reliable technical support for food safety risk monitoring.

Revealing the potential bioactive components and mechanism of Qianhua Gout Capsules in the treatment of gouty arthritis through network pharmacology, molecular docking and pharmacodynamic study strategies

Recent clinical studies have confirmed the effectiveness of Qianhua Gout Capsules (QGC) in the treatment of gouty arthritis (GA). However, the specific regulatory targets and mechanisms of action of QGC are still unclear. To address this gap, we utilized network pharmacology, molecular docking, and pharmacodynamic approaches to investigate the bioactive components and associated mechanisms of QGC in the treatment of GA. By employing UPLC-Q Exactive-MS, we identified the compounds present in QGC, with active ingredients defined as those with oral bioavailability ≥30 % and drug similarity ≥0.18. Subsequently, the targets of these active compounds were determined using the TCMSP database, while GA-related targets were identified from DisGeNET, GeneCards, TTD, OMIM, and DrugBank databases. Further analysis including PPI analysis, GO analysis, and KEGG pathway enrichment was conducted on the targets. Validation of the predicted results was performed using a GA rat model, evaluating pathological changes, inflammatory markers, and pathway protein expression. Our results revealed a total of 130 components, 44 active components, 16 potential shared targets, GO-enriched terms, and 47 signaling pathways related to disease targets. Key active ingredients included quercetin, kaempferol, β-sitosterol, luteolin, and wogonin. The PPI analysis highlighted five targets (PPARG, IL-6, MMP-9, IL-1β, CXCL-8) with the highest connectivity, predominantly enriched in the IL-17 signaling pathway. Molecular docking experiments demonstrated strong binding of CXCL8, IL-1β, IL-6, MMP9, and PPARG targets with the top five active compounds. Furthermore, animal experiments confirmed the efficacy of QGC in treating GA in rats, showing reductions in TNF-α, IL-6, and MDA levels, and increases in SOD levels in serum. In synovial tissues, QGC treatment upregulated CXCL8 and PPARG expression, while downregulating IL-1β, MMP9, and IL-6 expression. In conclusion, this study applied a network pharmacology approach to uncover the composition of QGC, predict its pharmacological interactions, and demonstrate its in vivo efficacy, providing insights into the anti-GA mechanisms of QGC. These findings pave the way for future investigations into the therapeutic mechanisms underlying QGC's effectiveness in the treatment of GA.

Simultaneous determination of 15 pyrrolizidine alkaloids and their N-oxides in weeds, soil, fresh tea leaves, and tea: Exploring the pollution source of pyrrolizidine alkaloids in tea

Pyrrolizidine alkaloids (PAs) and their N-oxides (PANOs) are novel contaminants in tea. However, the source of PA/PANO contamination in tea remains unclear. In this study, 15 PAs/PANOs were extracted from plant samples (tea, fresh tea leaves, and weeds) with 0.1 M sulfuric acid and from soil with 0.1 M sulfuric acid methanol after adjusting soil acidity with 0.1 M trisodium citrate. Satisfactory recoveries of PAs/PANOs from four different matrices at 0.02, 0.1, and 0.5 mg kg-1 was 72%-114% with relative standard deviations (RSD) of 0.03%-16%. Seven out of 15 PAs/PANOs were detected in tea purchased from the local market ranging from undetected to 96.2 μg kg-1. Thirteen, three, and four PAs/PANOs were detected in weeds, fresh tea leaves, and soil, respectively. Based on the types of PAs/PANOs detected in the three matrices, it was preliminarily speculated that PAs/PANOs in tea originated from weeds in the tea garden.

Pyrrolizidine Alkaloids in Tea (Camellia sinensis L.) from Weeds through Weed-Soil-Tea Transfer and Risk Assessment of Tea Intake

Pyrrolizidine alkaloids (PAs) have been detected in tea and can threaten human health. However, the specific source of PAs in tea is still unclear. Here, 88 dried tea products collected from six major tea-producing areas in Anhui Province, China, were analyzed. The detection frequency was 76%. The content of total PAs in dried tea was between 1.1 and 90.5 μg/kg, which was all below the MRL recommended by the European Union (150 μg/kg). In the Shexian tea garden, PAs in the weeds and weed rhizospheric soil around tea plants and the fresh tea leaves were analyzed. Intermedine (Im), intermedine-N-oxide (ImNO), and jacobine-N-oxide (JbNO) were transferred through the weed-to-soil-to-tea route into the fresh tea leaves; only Im and ImNO were detected in dried tea samples. Potential risk of the total PAs in the tea infusion was assessed according to the margin of exposure method, and it might be a low concern for public health.

Pyrrolizidine alkaloids in borage (Borago officinalis): Comprehensive profiling and development of a validated LC-MS/MS method for quantification

Pyrrolizidine alkaloids (PA) from borage (Borago officinalis) consumed as herb and tea, may pose a food safety risk. Therefore, the European Union (EU) set maximum levels of PA in borage, among other foodstuffs, which are applicable since July 1^st, 2022. Here, a comprehensive LC-MS/MS based profiling of PA and their N-oxides (PANO) in B. officinalis leaves is presented. Based on these results a targeted, quantitative LC-MS/MS method for the determination of individual PA/PANO present in borage was developed. Chromatographic separation was achieved for all PA/PANO detected in B. officinalis. An easy and fast extraction procedure was developed using a design of experiments approach (DOE). The most efficient extraction was achieved using 0.2% formic acid in 10% methanol at a temperature of 47.5 °C for 60 min. The final method was validated and showed good overall accuracy (recoveries 85-121%) and precision (RDS ≤11%). The method was applied to B. officinalis leave material, demonstrating its suitability for the intended purpose. In these borage samples, the acetylated forms, which are not regulated by EU, were among the quantitatively most relevant PA.

Pyrrolizidine-producing weeds in tea gardens as an indicator of alkaloids in tea

Pyrrolizidine alkaloids (PAs) can be transferred between plants via soil. Indicators of PAs in tea products are useful for tea garden management. In the present work a total of 37 weed species, 37 weed rhizospheric soils and 24 fresh tea leaf samples were collected from tea gardens, in which PAs were detected in 35 weeds species, 21 soil samples and 10 fresh tea leaves samples. In Shexian tea garden, 12.9 μg/kg of intermedine (Im) in one bud plus three leaves, 1.40 and 14.6 μg/kg of intermedine-N-oxide (ImNO) in one bud plus two leaves and one bud plus three leaves were detected, which were transferred from the PA-producing weeds via soil. However, no PAs were detected in fresh tea leaves collected from Langxi tea garden. The results indicated that synthesis of PAs in weeds and their transfer through the weed-soil-fresh tea leaf route varied with soil environments in different tea gardens.

Pyrrolizidine Alkaloid Extraction and Analysis: Recent Updates

Pyrrolizidine alkaloids are natural secondary metabolites that are mainly produced in plants, bacteria, and fungi as a part of an organism's defense machinery. These compounds constitute the largest class of alkaloids and are produced in nearly 3% of flowering plants, most of which belong to the Asteraceae and Boraginaceae families. Chemically, pyrrolizidine alkaloids are esters of the amino alcohol necine (which consists of two fused five-membered rings including a nitrogen atom) and one or more units of necic acids. Pyrrolizidine alkaloids are toxic to humans and mammals; thus, the ability to detect these alkaloids in food and nutrients is a matter of food security. The latest advances in the extraction and analysis of this class of alkaloids are summarized in this review, with special emphasis on chromatographic-based analysis and determinations in food.

In-House Validation of an Efficient and Rapid Procedure for the Simultaneous Determination and Monitoring of 23 Mycotoxins in Grains in Korea

A high-performance liquid chromatography tandem mass spectrometry method is described for the simultaneous determination of mycotoxins, including Ergot alkaloids (EAs), in 3 types of grains. The extraction of 23 mycotoxins was evaluated and performed by using a modified QuEChERS-based sample preparation procedure. The proposed method was fully validated on spiked grain samples (barley, wheat and oat) to assess the linearity, limit of detection (LOD) and limit of quantitation (LOQ), matrix effects, precision and recovery. After validation, this method was applied to 143 samples of various types of 3 grains from the Republic of Korea to survey the level of mycotoxin contamination in Republic of Korean grains. A total of 42 grain samples (29%) were contaminated with at least one of these mycotoxins at levels higher than the LOQ. The results demonstrated that the procedure was suitable for simultaneously determining these mycotoxins in cereals and could be performed for their routine analysis in mycotoxin laboratories.

Nanoflow liquid chromatography mass spectrometry method for quantitative analysis and target ion screening of pyrrolizidine alkaloids in honey, tea, herbal tinctures, and milk

A method for the determination of pyrrolizidine alkaloids in tea, honey, herbal tinctures, and milk samples was developed by employing nano-LC-MS with high-resolution Orbitrap mass spectrometry. Quantitation was performed using the available analytical standards, and a MS² target ion screening approach was developed using fragment ions that were specific for pyrrolizidine alkaloids under collision-induced dissociation. Proof of concept was delivered for the screening approach, proposing that the C₆H₈N⁺ fragment ion is a highly selective fragment ion for the detection of potential pyrrolizidine alkaloids. The elaborated quantitation was applied for the occurrence study of pyrrolizidine alkaloids in food products available on the Latvian market, including samples of tea (n = 15), honey (n = 40), herbal tinctures (n = 15), and milk (n = 10). The median LOQ over all analytes was 0.33 µg kg^-1 in honey, 3.6 µg kg^-1 in tea, 3.3 µg kg^-1 in herbal tinctures, and 0.32 µg kg^-1 in milk. The herbal tinctures samples and milk samples did not contain pyrrolizidine alkaloids above LOQ values. Analytes were detected in 33% of honey and 47% of tea samples. Most common were echimidine, intermedine, and enchinatine N-oxide. Pyrrolizidine alkaloids in tea samples were mainly N-oxides, with the highest total concentration being 215 µg kg^-1 among the samples, exceeding the maximum limit of 200 µg kg^-1 set by Commission Regulation (EU) 2020/2040. In honey samples, lycopsamine-type alkaloids were detected most frequently, with the highest total concentration equal to 74 µg kg^-1. Advantages of the developed nano-LC-MS methods included increased sensitivity in comparison with conventional flow LC-MS, low solvent consumption typical with nano-LC and the novel use of a selective common target ion for detection and discovery of potential pyrrolizidine alkaloids using high resolution mass spectrometry.

Application of the QuEChERS Strategy as a Useful Sample Preparation Tool for the Multiresidue Determination of Pyrrolizidine Alkaloids in Food and Feed Samples: A Critical Overview

The identification of concerning high levels of pyrrolizidine alkaloids (PAs) in a wide variety of food products has raised the occurrence of these natural toxins as one of the main current issues of the food safety field. Consequently, a regulation with maximum concentration levels of these alkaloids has recently been published to monitor their occurrence in several foodstuffs. According to legislation, the analytical methodologies developed for their determination must include multiresidue extractions with high selectivity and sensitivity, as a set of 21 + 14 PAs should be simultaneously monitored. However, the multiresidue extraction of these alkaloids is a difficult task due to the high complexity of food and feed samples. Accordingly, although solid-phase extraction is still the technique most widely used for sample preparation, the QuEChERS method can be a suitable alternative for the simultaneous determination of multiple analytes, providing green extraction and clean-up of samples in a quick and cost-effective way. Hence, this review proposes an overview about the QuEChERS concept and its evolution through different modifications that have broadened its applicability over time, focusing mainly on its application regarding the determination of PAs in food and feed, including the revision of published works within the last 11 years.

Study of the occurrence of toxic alkaloids in forage grass by liquid chromatography tandem mass spectrometry

The toxic alkaloids in forage grass present a serious health hazard to humans and livestock, especially ergot alkaloids (EAs), pyrrolizidine alkaloids (PAs) and tropane alkaloids (TAs). Hence, there is a need for a simultaneous method that allows these dangerous plant toxins to be determined. A simple and effective method was developed to determine fifteen toxic alkaloids (EAs, PAs and TAs) in forage grass using the QuEChERS method and liquid chromatography tandem mass spectrometry (LC-MS/MS). The developed method was validated with average recoveries ranging from 63.10 to 102.10%, and relative standard deviations lower than or equal to 6.39% were obtained. Good linearity over the concentration range of 10-600 µg/kg dry matter (DM) was observed for the target alkaloids. The determination coefficients R² calculated for each of the matrix calibration curves were greater than 0.99. The limits of detection and quantification were 5 µg/kg DM and 10 µg/kg DM, respectively. The reproducibility of the method was verified in three laboratories: all of the mean recoveries of 15 alkaloids were higher than 60%, and the relative standard deviations in alkaloids between laboratories were all less than 14.24%. The proposed method was applied to analyse 134 forage grass samples from the meadow steppe of Inner Mongolia to monitor toxic alkaloids. A significant difference in the frequency of contamination was found between different herbage species and different regions.

High resolution mass spectrometry workflow for the analysis of food contaminants: Application to plant toxins, mycotoxins and phytoestrogens in plant-based ingredients

An analytical workflow including mass spectral library, generic sample preparation, chromatographic separation, and analysis by high-resolution mass spectrometry (HRMS) was developed to gain insight into the occurrence of plant toxins, mycotoxins and phytoestrogens in plant-based food. This workflow was applied to 156 compounds including 90 plant toxins (pyrrolizidine alkaloids, tropane alkaloids, glycoalkaloids, isoquinoline alkaloids and aristolochic acids), 54 mycotoxins (including ergot alkaloids and Alternaria toxins) and 12 phytoestrogens (including isoflavones, lignans and coumestan) in plant-based protein ingredients, cereal and pseudo-cereal products. A mass spectral library was built based on fragmentation spectra collected at 10 different collision energies in both positive and negative ionisation modes for each toxin. Emphasis was put on a generic QuEChERS-like sample preparation followed by ultra-high-pressure liquid chromatography using alkaline mobile phase allowing the separation of more than 50 toxic pyrrolizidine alkaloids. HRMS acquisition comprised a full-scan event for toxins detection followed by data-dependent MS2 for toxin identification against mass spectrum. Method performance was evaluated using fortified samples in terms of sensitivity, repeatability, reproducibility and recovery. All toxins were positively identified at levels ranging from 1 µg kg-1 to 100 µg kg-1. Quantitative results obtained by a standard addition approach met SANTE/12682/2019 criteria for 132 out of 156 toxins. Such a workflow using generic, sensitive and selective multi-residue method allows a better insight into the occurrence of regulated and non-regulated toxins in plant-based foods and to conduct safety evaluation and risk assessments when needed.

Comparative Risk Assessment of Three Native Heliotropium Species in Israel

Pyrrolizidine alkaloids (PAs) are genotoxic carcinogenic phytotoxins mostly prevalent in the Boraginaceae, Asteraceae and Fabaceae families. Heliotropium species (Boraginaceae) are PA-producing weeds, widely distributed in the Mediterranean region, that have been implicated with lethal intoxications in livestock and humans. In Israel, H. europaeum, H. rotundifolium and H. suaveolens are the most prevalent species. The toxicity of PA-producing plants depends on the PA concentration and composition. PAs occur in plants as mixtures of dozens of various PA congeners. Hence, the risk arising from simultaneous exposure to different congeners has to be evaluated. The comparative risk evaluation of the three Heliotropium species was based on recently proposed interim relative potency (iREP) factors, which take into account certain structural features as well as in vitro and in vivo toxicity data obtained for several PAs of different classes. The aim of the present study was to determine the PA profile of the major organ parts of H. europaeum, H. rotundifolium and H. suaveolens in order to assess the plants' relative toxic potential by utilizing the iREP concept. In total, 31 different PAs were found, among which 20 PAs were described for the first time for H. rotundifolium and H. suaveolens. The most prominent PAs were heliotrine-N-oxide, europine-N-oxide and lasiocarpine-N-oxide. Europine-N-oxide displayed significant differences among the three species. The PA levels ranged between 0.5 and 5% of the dry weight. The flowers of the three species were rich in PAs, while the PA content in the root and flowers of H. europaeum was higher than that of the other species. H. europaeum was found to pose a higher risk to mammals than H. rotundifolium, whereas no differences were found between H. europaeum and H. suaveolens as well as H. suaveolens and H. rotundifolium.

The invasive butterbur contaminates stream and seepage water in groundwater wells with toxic pyrrolizidine alkaloids

Pyrrolizidine alkaloids (PAs) are persistent mutagenic and carcinogenic compounds produced by many common plant species. Health authorities recommend minimising human exposure via food and medicinal products to ensure consumer health and safety. However, there is little awareness that PAs can contaminate water resources. Therefore, no regulations exist to limit PAs in drinking water. This study measured a PA base concentration of ~ 70 ng/L in stream water adjacent to an invasive PA-producing plant Petasites hybridus (Asteraceae). After intense rain the PA concentration increased tenfold. In addition, PAs measured up to 230 ng/L in seepage water from groundwater wells. The dominant PAs in both water types corresponded to the most abundant PAs in the plants (senkirkine, senecionine, senecionine N-oxide). The study presents the first discovery of persistent plant toxins in well water and their associated risks. In addition, it for the first time reports monocrotaline and monocrotaline N-oxide in Petasites sp.

Preincubation format for a sensitive immunochromatographic assay for monocrotaline, a toxic pyrrolizidine alkaloid

INTRODUCTION

Monocrotaline (MCT), which is classified as a 1,2-dehydropyrrolizidine alkaloid (DHPA), is a toxic compound that is mainly produced by Crotalaria spp. MCT contamination in cereals and herbs leads to hepatitis, gastroenteritis, pulmonary vasculitis and hypertension, and different types of cancer. The current analytical methods for MCT are complicated and expensive using liquid chromatography equipped with mass spectrometry detection.

OBJECTIVE

The aim of this study was to develop a simple and sensitive preincubation format for an immunochromatographic assay (PI-ICA) for MCT detection.

METHODOLOGY

We conducted the PI-ICA via incubation of an MCT-containing sample with an anti-MCT monoclonal antibody conjugated with colloidal gold before strip dipping. We compared the PI-ICA detection sensitivity with that of the conventional ICA (Conv-ICA) format.

RESULTS

The PI-ICA was sensitive with a limit of detection (LOD) of 0.61 ng/mL, which is a 16-fold improvement over the Conv-ICA format. These results indicated that the PI-ICA method exhibits high binding specificity for MCT and low cross-reactivity towards retronecine, retrorsine, senecionine and heliotrine. Sample solutions from plants containing MCT and related DHPAs produced positive results via PI-ICA analysis.

CONCLUSIONS

The proposed PI-ICA system provides a highly sensitive method compared to Conv-ICA. In addition, the developed PI-ICA method is simple and highly effective for detecting MCT contamination.

Simultaneous Determination and Risk Assessment of Pyrrolizidine Alkaloids in Artemisia capillaris Thunb. by UPLC-MS/MS Together with Chemometrics

Pyrrolizidine alkaloids (PAs) are natural toxins found in some genera of the family Asteraceae. However, it has not been reported whether PAs are present in the widely used Asteraceae plant Artemisia capillaris Thunb. (A. capillaris). The purpose of this study was to establish a sensitive and rapid UPLC-MS/MS method together with chemometrics analysis for simultaneous determination and risk assessment of PAs in A. capillaris. The developed UPLC-MS/MS method was validated and was confirmed to display desirable high selectivity, precision and accuracy. Risk assessment was conducted according to the European Medicines Agency (EMA) guideline. Chemometrics analysis was performed with hierarchical clustering analysis and principal component analysis to characterize the differences between PAs of A. capillaris. Finally, PAs were found in 29 out of 30 samples and at least two were detected in each sample, besides, more than half of the samples exceeded the EMA baseline. Nevertheless, the chemometrics results suggested that the PAs contents of A. capillaris from different sources varied significantly. The method was successfully applied to the detection and risk evaluation of PAs-containing A. capillaris for the first time. This study should provide a meaningful reference for the rational and safe use of A. capillaris.

Simultaneous determination of pesticides, mycotoxins, tropane alkaloids, growth regulators, and pyrrolizidine alkaloids in oats and whole wheat grains after online clean-up via two-dimensional liquid chromatography tandem mass spectrometry

In this study, a two-dimensional liquid chromatography tandem mass spectrometry method was developed and validated for the determination of pesticide residues and contaminants in whole wheat grains and oats. The samples were extracted with a mixture of acetonitrile and water and were injected into the two-dimensional LC-MS/MS system without any further clean-up or sample preparation. Samples were analyzed with four different matrix matched calibrations. Matrix effects were evaluated by comparing analyte signals in the respective matrix matched standard with the neat solvent standards. The final method was validated according to the current Eurachem validation guide and SANTE document. The number of successfully validated analytes throughout all three validation levels in oats and wheat, respectively, were as follows: 330 and 316 out of 370 pesticides, 6 and 13 out of 18 pyrrolizidine alkaloids and 7 out of 9 regulated mycotoxins. Moreover, both plant growth regulators mepiquat and chlormequat as well as the tropane alkaloids atropine and scopolamine met the validation criteria. The majority of pesticides showed limits of detection below 1 µg kg^-1, pyrrolizidine alkaloids below 0.7 µg kg^-1, tropane alkaloids below 0.2 µg kg^-1, growth regulators below 0.7 µg kg^-1 and mycotoxins below 8 µg kg^-1 in both matrices.

Pyrrolizidine alkaloids quantified in soil and water using UPLC-MS/MS

Pyrrolizidine alkaloids (PAs) are produced in plants as defence compounds against insects. PAs present a serious health risk to humans and livestock; therefore it is necessary to have a validated analytical method to monitor PAs in the environment. The objective of this work is to present an UPLC-MS/MS method for quantification of PAs in environmental samples of both soil and water. A fast, reliable, and sensitive approach is developed to identify and quantify PAs in soil and water. Sample preparation was performed by clean-up and pre-concentration of the samples using MCX solid phase extraction cartridges with full optimization, and then PAs were determined by UPLC coupled with TQ-MS. In the liquid chromatography, most of the parameters were optimized and tested including gradient time, solvents, additives, and pH of the mobile phases and flow rate. In addition, the MS parameters of cone voltage, desolvation temperature, cone flows, and collision energy were optimized. The instrument limit of detection (2–7 μg L⁻¹) and limit of quantification (5–9 μg L⁻¹) were determined experimentally, and the method was linearity validated up to 1000 μg L⁻¹. The method was applied to analyse soil and surface water samples collected in April and May 2018 in Vejle, Borup, and Holte, Denmark. In total, 15 PAs were quantified and reported for the first time in environmental samples, in a range of 3–1349 μg kg⁻¹ in soil and 4–270 μg L⁻¹ in surface water.

Pyrrolizidine alkaloids quantified in soil and water.

Use of a New LC-MS Method for The Determination of Pyrrolizidine Alkaloids in Feeds

INTRODUCTION

Pyrrolizidine alkaloids (PAs) are secondary metabolites produced by many plant species. Due to their toxicity PAs can pose a risk to human and animal health. To detect the toxic compounds in feed materials a sensitive method based on liquid chromatography coupled with mass spectrometry has been developed.

MATERIAL AND METHODS

PAs were extracted with sulphuric acid and purified with cation exchange cartridges. A newly developed solvent mixture consisting of ethyl acetate, methanol, acetonitrile, ammonia, and triethylamine was used to wash alkaloids from the cartridges. After evaporation the residues were reconstituted in water and methanol mixture and subjected to LC-MS analysis.

RESULTS

The developed method was validated according to SANTE/11945/2015 guidelines. The recovery was from 84.1% to 112.9%, the repeatability ranged from 3.0% to 13.6%, and the reproducibility was from 4.8% to 18.9%.

CONCLUSIONS

A sensitive and selective method for determination of PAs in feed materials has been developed and validated. All evaluated validation parameters were in accordance with EU Reference Laboratories document no. SANTE/11945/2015. Almost 41% of the analysed feed samples were positive for the presence of at least one PA.

Determination of armepavine in mouse blood by UPLC-MS/MS and its application to pharmacokinetic study

The purpose of this study was to develop an ultra-performance liquid chromatography with tandem mass spectrometry (UPLC-MS/MS) method to determine armepavine in mouse blood. Nuciferine was used as internal standard. Chromatographic separation was performed on a UPLC BEH (2.1 × 50 mm, 1.7 μm) column with a gradient elution of acetonitrile and 10 mmol/L ammonium acetate solution (containing 0.1% formic acid). The quantitative analysis was conducted in multiple reaction monitoring mode with m/z 314.1 → 106.9 for armepavine and m/z 296.2 → 265.1 for nuciferine. Calibration curves were linear (r > 0.995) over the concentration range 1-1000 ng/mL in mouse blood with a lowest limit of quantitation of 1 ng/mL. The intra- and inter-day precisions of armepavine in mouse were < 13.5 and 10.8%, respectively. The accuracy ranged between 86.8 and 103.3%. Meanwhile, the average recovery was >70.7% and the matrix effect was within the range 109.5-113.7%. All of the obtained data confirmed the satisfactory sensitivity and selectivity of the developed method which was then successfully applied to evaluate the pharmacokinetic behavior of armepavine in mouse for the first time. The bioavailability of armepavine in mouse was calculated to be 11.3%.

Influence of grass pellet production on pyrrolizidine alkaloids occurring in Senecio aquaticus-infested grassland

1,2-Dehydro-pyrrolizidine alkaloids (PA) and their N-oxides (PANO) exhibit acute and chronic toxic effects on the liver and other organs and therefore are a hazard for animal and human health. In certain regions of Germany, an increasing spread of Senecio spp. (ragwort) on grassland and farmland areas has been observed during the last years leading to a PA/PANO-contamination of feed and food of animal and plant origin. This project was carried out to elucidate whether the process of grass pellet production applying hot air drying influences the content of PA and PANO. Samples of hay (n = 22) and grass pellets (n = 28) originated from naturally infested grassland (around 10% and 30% dominance of Senecio aquaticus) and from a trial plot with around 50% dominance. Grass pellets were prepared from grass originating from exactly the same plots as the hay samples. The samples were analysed by liquid chromatography-tandem mass spectrometry for PA/PANO typically produced by this weed. The results of the study revealed that PA/PANO levels (predominantly sum of senecionine, seneciphylline, erucifoline and their N-oxides) in hay ranged between 2.1 and 12.6 mg kg^-1 dry matter in samples with 10% and 30% dominance of S. aquaticus, respectively. Samples from the trial plot (50% dominance) had levels of up to 52.9 mg kg^-1. Notably, the hot air drying process during the production of grass pellets did not lead to a reduction of PA/PANO levels. Instead, the levels in grass pellets with 10% and 30% S. aquaticus ranged from 3.1 to 55.1 mg kg^-1. Grass pellets from the trial plot contained up to 96.8 mg kg^-1. In conclusion, hot air drying and grass pellet production did not affect PA/PANO contents in plant material and therefore, heat-dried products cannot be regarded as safe in view of the toxic potential of 1,2-dehydro-pyrrolizidine alkaloids.

Ultra-Performance Liquid Chromatography Hyphenated with Quadrupole-Orbitrap Mass Spectrometry for Simultaneous Determination of Necine-Core-Structure Pyrrolizidine Alkaloids in Crotalaria sessiliflora L. without all Corresponding Standards

INTRODUCTION

Crotalaria sessiliflora L. is a Chinese traditional herb for treatment of cutaneum carcinoma and cervical carcinoma. In addition to monocrotaline, coexisting pyrrolizidine alkaloids (PAs) also require further quantification for quality control and pharmaceutical uses of the herb.

OBJECTIVE

To establish a UPLC-Q-Orbitrap/MS method of simultaneous determination of coexisting PAs with same parent structure for quality control and comprehensive researches of Crotalaria sessiliflora L.

METHODOLOGY

PAs in Crotalaria sessiliflora L. were analysed by UPLC-Q-Orbitrap/MS method. Coexisting PAs were identified by mass data of full MS-dd-MS² based on the characteristic fragmentation pattern and necine-core structure. Moreover, quantification of PAs was conducted by parallel reaction monitoring (PRM) mode using m/z 138, m/z 120 and m/z 94 from identical necine-core structure as quantitative ions with single monocrotaline standard for accurate calibration.

RESULTS

Five PAs, named monocrotaline, retrorsine, senecionine, integerrimine, O-9-angeloylretronecine, were indentified and confirmed. Quantitative ions of m/z 138, m/z 120 and m/z 94 were used for quantification of PAs containing the necine-core structure in Crotalaria sessiliflora L. The results demonstrated that contents, precision and recoveries of the five PAs mentioned earlier were respectively 3.307-30.35 μg/g, 1.1-4.5% and 88.91-92.33% while using m/z 120 as the best quantitative ion.

CONCLUSION

The UPLC-Q-Orbitrap/MS method was established for simultaneous determination of five PAs in Crotalaria sessiliflora L. without all corresponding standards, and was proved that it was simple, convenient and effective for comprehensive quality control and pharmaceutical uses. Copyright © 2017 John Wiley & Sons, Ltd.

Development of an analytical method for identification of Aspergillus flavus based on chemical markers using HPLC-MS

Aspergillus flavus is a filamentous fungus found in nature and characterized by the production of bright and colourful colonies. It grows on different substrates, producing secondary metabolites and, if present in foodstuffs, can be a source of health problems for humans and animals, as well as causing economic losses. Traditional methods for fungal identification are based on morphological characteristics, requiring specialists and being very time-consuming. The development of analytical alternatives might have advantages such as greater efficiency, more reproducibility and be less time-consuming. Thus, a qualitative analytical method to detect Aspergillus flavus in food samples, based on the identification of fungal chemical markers by HPLC-MS, was developed. The method comprises methanol extraction followed by HPLC-MS analysis, and was able to identify 14 fungus secondary metabolites, namely aflatoxin B1, aflatoxin G1, aspergillic acid, aspyrone, betaine, chrysogine, deacetyl parasiticolide A, flufuran, gregatin B, hydroxysydonic acid, nicotinic acid, phomaligin A, spinulosin and terrein.

Pyrrolizidine alkaloids: occurrence, biology, and chemical synthesis

Covering: 2013 up to the end of 2015This review covers the isolation and structure of new pyrrolizidines; pyrrolizidine biosynthesis; biological activity, including the occurrence of pyrrolizidines as toxic components or contaminants in foods and beverages; and formal and total syntheses of naturally-occurring pyrrolizidine alkaloids and closely related non-natural analogues.

Determination of pyrrolizidine alkaloids in selected feed materials with gas chromatography-mass spectrometry

1,2-Dehydropyrrolizidine alkaloids are known to be toxic to many animals and humans. To provide safety of feeds a method based on gas chromatography-mass spectrometry enabling the determination of a content of 1,2-unsaturated PAs in feed materials was developed. After extraction with aqueous solution of HCl and purification of the extract, 1,2-unsaturated alkaloids are reduced to their common backbone structures and subsequently derivatised with heptafluorobutyric anhydride (HFBA). The method was validated according to SANTE/11945/2015. All received parameters are consistent with the document requirements as recovery of a final compound retronecine derivative was from 81.8% to 94.4% when retrosine was used for spiking and from 72.7% to 85.5% when retrorsine N-oxide was spiked. The repeatability was calculated as relative standards deviation and ranged from 7.5% to 14.4%, for N-oxide was from 7.9% to 15.4%. The reproducibility was in the range from 14.2% to 16.3% and from 17.0% to 18.1% for free base and N-oxide respectively. The limit of quantification was determined as 10 µg kg^-1. Good linearity of the method was obtained with coefficient of determination R² > 0.99. The method was applied to 35 silage and two hay samples analysis.