Pyrrolizidine Alkaloids In Honey Research Articles

Pyrrolizidine Alkaloids as Hazardous Toxins in Natural Products: Current Analytical Methods and Latest Legal Regulations.

Pyrrolizidine alkaloids (PAs) are toxic compounds that occur naturally in certain plants, however, there are many secondary pathways causing PA contamination of other plants, including medicinal herbs and plant-based food products, which pose a risk of human intoxication. It is proven that chronic exposure to PAs causes serious adverse health consequences resulting from their cytotoxicity and genotoxicity. This review briefly presents PA occurrence, structures, chemistry, and toxicity, as well as a set of analytical methods. Recently developed sensitive electrochemical and chromatographic methods for the determination of PAs in honey, teas, herbs, and spices were summarized. The main strategies for improving the analytical efficiency of PA determination are related to the use of mass spectrometric (MS) detection; therefore, this review focuses on advances in MS-based methods. Raising awareness of the potential health risks associated with the presence of PAs in food and herbal medicines requires ongoing research in this area, including the development of sensitive methods for PA determination and rigorous legal regulations of PA intake from herbal products. The maximum levels of PAs in certain products are regulated by the European Commission; however, the precise knowledge about which products contain trace but significant amounts of these alkaloids is still insufficient.

UHPLC-Q-TOF analysis of pyrrolizidine alkaloids in North-Macedonian honey

ABSTRACT Honey contaminated with pyrrolizidine alkaloids (PAs) could pose a risk for human consumption, being a widely consumed food product. A fast and simple LC/MS method for the analysis of pyrrolizidine alkaloids in honey was optimised to collect occurrence data. The extraction efficiency was evaluated by a systematic study of multiple solvent mixtures and clean-up procedures. The best results for PA extraction were obtained using a formic acid/methanol mixture with subsequent clean-up by the QuEChERS method, resulting in a mean recovery range of 91.8–102%. The method validation showed satisfactory intra-day (RSD < 5.1%) and inter-day precision (RSD < 9.1%). The proposed method was applied to 14 samples. A total of six PAs and two N-oxides were detected, with levels between 89 and 8188 µg/kg. This assessment highlights the potential risk of intoxication and the need for further investigations regarding an effective quality system for manufacturers to control PAs in honey.

Pyrrolizidine Alkaloids from Monofloral and Multifloral Italian Honey

Pyrrolizidine alkaloids (PAs) are secondary metabolites produced by plants as a self-defense against insects. After bioactivation in the liver, some PAs can cause acute or chronic toxicity in humans. The aim of this study was to determine the presence of PAs in 121 samples of monofloral and multifloral honey from three different Italian regions (Friuli-Venezia Giulia, Marche and Calabria) to meet the European Food Safety Authority (EFSA) suggestion. An in-house liquid chromatography with tandem mass spectrometry (LC-MS/MS) method was validated according to European Union Reference Laboratory (EURL) performance criteria. This method allowed the detection and quantification of 35 PAs. Of the 121 honey samples, 38 (31%), mostly from Calabria, contained PAs. The total content of the PAs ranged from 0.9 µg/kg to 33.1 µg/kg. In particular, echimidine was the most prevalent PA. A rapid human exposure assessment to PAs in honey and a risk characterization was performed using the EFSA RACE tool. The assessment highlighted a potential health concern only for toddlers who frequently consume elevated quantities of honey. This study showed a low presence of PAs in Italian honey; however, the importance of continuously monitoring these compounds is stressed, along with the suggestion that the relevant authorities establish maximum limits to guarantee support for producers and consumer safety.

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.

High‐performance counter‐current chromatography purification and off‐line mass spectrometry monitoring and identification of pyrrolizidine alkaloid markers of tropical Ghanaian honey

The nutritional and medicinal properties of honey have been well-documented. However, honey has occasionally been contaminated with hepatotoxic pyrrolizidine alkaloids as a result of bees foraging on the flowers of pyrrolizidine alkaloid plants. This study establishes a simple and rapid method to determine the marker pyrrolizidine alkaloids in honey using high-performance counter-current chromatography and an off-line electrospray ionization-tandem mass spectrometry, in order to identify the botanical sources responsible for the contamination. The honey sample was initially liquid-liquid extracted (sulfuric acid/hexane, 2:3, v/v) to enrich the pyrrolizidine alkaloids and subsequently purified by a semi-preparative high-performance counter-current chromatography using a solvent system, hexane/butanol/1% aqueous ammonia, 1:1:2, v/v, based on partition coefficient measurements of the target alkaloids. The recovered fractions were profiled by injecting them sequentially into an off-line electrospray ionization-tandem mass spectrometry device to monitor the preparative molecular weight based on elution and extrusion modes. The monitored lycopsamine-type pyrrolizidine alkaloids and their N-oxides (m/z 300, 316; lycopsamine, intermedine, rinderine, and echinatine) were used as the phytochemical markers to identify plants like Chromolaena odorata, Ageratum spp., or Heliotropium spp. to be responsible for the pyrrolizidine alkaloid contamination. Identification of these pyrrolizidine alkaloid plants could guide beekeepers in locating their beehives in order to minimize their potential liver damaging effects.

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

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.

Comprehensive investigation and risk study on pyrrolizidine alkaloid contamination in Chinese retail honey

Pyrrolizidine alkaloids (PAs) are common phytotoxins. We performed the first comprehensive investigation on PA contamination in Chinese honeys. LC-MS analysis revealed that 58% of 255 honey samples purchased from 17 regions across Mainland China and Taiwan contained PAs with total content ranging over 0.2–281.1 μg/kg. Monocrotaline (from Crotalaria spp), a PA never found in honey in other regions, together with echimidine (Echium plantagineum) and lycopsamine (from Senecio spp.), were three predominant PAs in PA-contaminated Chinese honeys. Further, PAs present in honeys were found to have geographically distinct pattern, indicating possible control of such contamination in future honey production. Moreover, we proposed a new risk estimation approach, which considered both content and toxic potency of individual PAs in honeys, and found that 12% of the PA-contaminated Chinese honeys tested might pose potential health risk. This study revealed a high prevalence and potential health risk of PA contamination in Chinese honeys.

Straightforward Determination of Pyrrolizidine Alkaloids in Honey through Simplified Methanol Extraction (QuPPE) and LC-MS/MS Modes.

Contamination of honey with toxic pyrrolizidine alkaloids (PAs) and their N-oxides (PANOs) was assessed by dilution with acidic methanol and analysis through liquid chromatography (LC) coupled with tandem mass spectrometry (MS/MS) in three different modes. The hybrid linear trap/triple quadrupole (LC-QTRAP) instrument was used in precursor ion scan (PIS), enhanced product ion scan (EPI), and multiple reaction monitoring (MRM) mode. The parent ions from ions at m/z 120 or 138 amus, characteristic of all the toxic PAs and PANOs in the sample were first scanned by PIS. Then, the presence of each contaminant at specific retention times through its MS2 spectrum was confirmed by EPI. Finally, they were quantified in the MRM mode. The method was validated: recoveries 86–111%, relative standard deviation (RSD) <20%, at 20 and 40 μg/kg, except retrorsine, which showed a RSD of 30% at 20 μg/kg. Honey samples were analyzed and five of them showed levels of 40 μg/kg for the sum (PAs + PANOs). This approach allows the simultaneous determination of PAs and PANOs in honey, even if their chemical standards are not available.

Pyrrolizidine alkaloids in honey: Quantification with and without standards

Quantification of a large number of compounds in the absence of authentic standards is always a challenge. More than 600 pyrrolizidine alkaloids (PAs) have been found in plants however only limited number of PAs standards are commercially available. As PAs are the most widely distributed natural plant toxins with threat to human health, risk assessment calls for quantitative analytical methods with a wide scope including PAs without available standards. In this study, a method was developed that allows simultaneous quantification of 12 PAs in the honey samples by using HPLC-HRMS with authentic standards. This method was further extended to screen for other potential PAs in the honey using multi-target screening combined with a quantitative prediction model in the cases that authentic PAs were not available. The prediction model was subsequently validated by cross-validation and additional PAs standards which were not included in the model. The maximum concentration prediction error was 50.8%.

Pyrrolizidine Alkaloids in Honey: Determination with Liquid Chromatography-mass Spectrometry Method.

IntroductionPyrrolizidine alkaloids (PAs) are probably the most widespread toxins of natural origin. More than 6,000 plant species produce these toxic compounds. Bees can forage on flowers of plants producing PAs, which leads to contamination of honey with the toxic compounds. To determine the contamination of honey with PAs, a sensitive method based on liquid chromatography coupled with mass spectrometry has been developed.Material and MethodsPAs were extracted with 0.05 M sulphuric acid and purified with MCX cartridges. A solvent mixture consisting of ethyl acetate, methanol, acetonitrile, ammonia, and triethylamine (8:1:1:0.1:0.1, v/v) 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.ResultsThe developed method was validated according to SANTE/11945/2015 requirements. The recovery was from 80.6% to 114.5%. The repeatability ranged from 2.3% to 14.6%, and the reproducibility was from 4.9% to 17.7%.ConclusionsA new method for the determination of PAs in honey has been developed and validated. All evaluated parameters were in accordance with the SANTE/11945/2015 guidance document. Out of 50 analysed honey samples, 16 (32%) were positive for the content of at least one PA.

Determination of Pyrrolizidine Alkaloids in Honey with Sensitive Gas Chromatography-Mass Spectrometry Method

Pyrrolizidine alkaloids (PAs) are secondary metabolites produced by plants as a chemical defense against herbivores. Plants containing PAs are widely distributed in almost all geographical regions posing a risk of honey contamination. To provide safety of honey and decrease the potential risk for the consumers, a sensitive method based on gas chromatography-mass spectrometry enabling determination of a content of 1,2-unsaturated PAs in honey was developed. Honey samples were purified on MCX cartridges, and PAs were eluted with a solvent mixture consisting of ethyl acetate, methanol, ammonia, and triethylamine. Subsequently, 1,2-unsaturated alkaloids were reduced to their common backbone structures and derivatized with heptafluorobutyric anhydride. The method was validated according to SANTE 2015. All received parameters are in consistence with the document requirements as recovery ranged from 73.1 to 93.6%. The repeatability and reproducibility were calculated as relative standard deviation and ranged from 3.9 to 8.6% and from 10.6 to 17.8%, respectively. The limit of quantification was determined as 1 μg kg−1. Good linearity of the method was obtained with the coefficient of determination R2 > 0.99. The method was applied to 40 Polish and 14 Asian honey sample analyses.

Contamination of hepatotoxic pyrrolizidine alkaloids in retail honey in China

Pyrrolizidine alkaloids (PAs) are natural toxins present in over 6000 plants. Humans are exposed to PAs through the intake of PA-containing plants and/or PA-contaminated foodstuffs, such as honey. PA contamination in honey has been extensively studied in many countries, but rarely investigated in China. The present study investigated PA contamination in retail honey purchased in four representative regions (Hong Kong, Macau, Beijing, Shanghai) in China.Among 120 honey samples tested, 58% of them contained PAs with the concentration range over 0.04–288.07 μg/kg. The prevalence and content of PAs in honeys purchased in Hong Kong and Macau were significantly higher than those detected in Beijing and Shanghai. Lycopsamine and echimidine were determined as predominant PAs in the contaminated honeys, and their potential botanic sources including plants of Echium and Senecio genera were identified by pollen analysis. Moreover, clivorine, which has not been reported previously in PA-contaminated honey, was found with a high prevalence (34%) in PA-contaminated honeys in China.Our study represented an integrated report on PA contamination in retail honey in China. The data provided information useful for the global assessment of human risk posed by consumption of PA-contaminated honey.

Risks for human health related to the presence of pyrrolizidine alkaloids in honey, tea, herbal infusions and food supplements.

EFSA was asked by the European Commission to deliver a scientific opinion on the risks for human health related to the presence of pyrrolizidine alkaloids (PAs) in honey, tea, herbal infusions and food supplements and to identify the PAs of relevance in the aforementioned food commodities and in other feed and food. PAs are a large group of toxins produced by different plant species. In 2011, the EFSA Panel on Contaminants in the Food Chain (CONTAM Panel) assessed the risks related to the presence of PAs in food and feed. Based on occurrence data limited to honey, the CONTAM Panel concluded that there was a possible health concern for those toddlers and children who are high consumers of honey. A new exposure assessment including new occurrence data was published by EFSA in 2016 and was used to update the risk characterisation. The CONTAM Panel established a new Reference Point of 237 μg/kg body weight per day to assess the carcinogenic risks of PAs, and concluded that there is a possible concern for human health related to the exposure to PAs, in particular for frequent and high consumers of tea and herbal infusions. The Panel noted that consumption of food supplements based on PA‐producing plants could result in exposure levels too close (i.e. less than 100 times lower) to the range of doses known to cause severe acute/short term toxicity. From the analysis of the available occurrence data, the CONTAM Panel identified a list of 17 PAs of relevance for monitoring in food and feed. The Panel recommended continuing the efforts to monitor the presence of PAs in food and feed, including the development of more sensitive and specific analytical methods. A recommendation was also issued on the generation of data to identify the toxic and carcinogenic potency of the PAs commonly found in food.

Investigation of pyrrolizidine alkaloids including their respective N-oxides in selected food products available in Hong Kong by liquid chromatography electrospray ionisation mass spectrometry

ABSTRACTThis study determined the levels of pyrrolizidine alkaloids (PAs), including their respective N-oxides, in foodstuffs available in Hong Kong by liquid chromatography-electrospray ionisation tandem mass spectrometry. A total of 234 samples (48 food items) were collected randomly from a local market and analysed. About 50% of samples were found to contain detectable amount of PAs. Amongst the 48 food items, PAs were not detected in 11 food items, including barley flour, beef, cattle liver, pork, pig liver, chicken meat, chicken liver, milk, non-fermented tea, Melissa tea and linden tea. For those found to contain detectable PAs, the summed PA content ranged up to 11,000 µg kg−1. The highest sum of PA content among the 37 food items calculated with lower bound was cumin seed, then followed by oregano, tarragon and herbs de Provence with ranges of 2.5–11,000, 1.5–5100, 8.0–3300 and 18–1300 µg kg−1 respectively. Among the samples, the highest sum of PA content was detected in a cumin seed sample (11,000 µg kg−1), followed by an oregano (5100 µg kg−1), a tarragon (3300 µg kg−1) and a herbs de Provence (1300 µg kg−1). In general, the results of this study agreed well with other published results in peer-reviewed journals, except that the total PAs in honey and specific tea infusion in this study were comparatively lower.

Pyrrolizidine Alkaloids from Echium vulgare in Honey Originate Primarily from Floral Nectar.

Pyrrolizidine alkaloids (PAs) in honey can be a potential human health risk. So far, it has remained unclear whether PAs in honey originate from pollen or floral nectar. We obtained honey, nectar, and plant pollen from two observation sites where Echium vulgare L. was naturally abundant. The PA concentration of honey was determined by targeted analysis using a high pressure liquid chromatography-mass spectrometry system (HPLC-MS/MS), allowing the quantification of six different PAs and PA-N-oxides present in E. vulgare. Echium-type PAs were detected up to 0.153 μg/g in honey. Nectar and plant pollen were analyzed by nontargeted analysis using ultrahigh pressure liquid chromatography-high resolution-mass spectrometry (UHPLC-HR-MS), allowing the detection of 10 alkaloids in small size samples. Echium-type PAs were detected between 0.3-95.1 μg/g in nectar and 500-35000 μg/g in plant pollen. The PA composition in nectar and plant pollen was compared to the composition in honey. Echimidine (+N-oxide) was the main alkaloid detected in honey and nectar samples, while echivulgarine (+N-oxide) was the main PA found in plant pollen. These results suggest that nectar contributes more significantly to PA contamination in honey than plant pollen.

A fast and simple LC-ESI-MS/MS method for detecting pyrrolizidine alkaloids in honey with full validation and measurement uncertainty

A fast and simple method was developed to determine pyrrolizidine alkaloids (PAs) in honey using liquid chromatography tandem mass spectrometry (LC- MS/MS) with electrospray ionization (ESI). An efficient extraction procedure was carried out by simply diluting with water, without the need of any additional clean-up steps. A full validation of the method was performed according to Commission Decision 2002/657/EC. The method was linear in the 050 μg kg−1 range and presented satisfactory intra-day and inter-day precision with relative standard deviations of 1.45–10.2% and 1.60–1–0.2%, respectively. The measurement uncertainty, limit of detection (LOD) (0.1–1.0 μg kg−1) and limit of quantification (LOQ) (0.2–1.5 μg kg−1) were also calculated. The proposed method was applied to analyse eight PAs, namely, senecionine, senecionine-N-oxide, echimidine, intermedine, lycopsamine, retrorsine, monocrotaline and retrorsine-N-oxide, in 92 commercial honey samples from Brazil. At least three PAs were detected in 99.1% of the samples. PAs were not detectable (<LOD) in only one sample. Because PAs are natural toxins biosynthesized by plants, the importance of monitoring their concentration in honey is evident. For this purpose, a simple, low-cost extraction procedure was performed, and a high-throughput method was developed.

Evaluation of Some Pyrrolizidine Alkaloids in Honey Samples from the Veneto Region (Italy) by LC-MS/MS

Pyrrolizidine alkaloids (PAs) are natural toxins, supposed to be converted to hepatotoxic metabolites in the liver of mammalians, and preventing the uptake of PAs is the only way to reduce the attendant health risks. A liquid chromatography coupled to mass spectrometry (LC-MS/MS) method was developed according to the Decision 2002/657/EC, to evaluate the contamination of Veneto honey by the following pyrrolizidine alkaloids: echimidine, heliotrine, lycopsamine, retrorsine, senecionine, and seneciphylline, as well as their N-oxides (pyrrolizidine alkaloid N-oxides (PANOs)). Before the solid-phase extraction, a reduction step with zinc dust in the presence of sulfuric acid was carried out for the reduction of PANOs to PAs in honey samples. For all of the analytes, the mean recovery ranged between 82.70 and 104.16 % and the limit of quantification (LOQ) was 0.25 μg kg−1, fully satisfying the LOQ of 1 μg kg−1 as requested by EFSA (2012). The validated method was applied for the analysis of 60 Veneto samples produced from local beekeepers. Among the samples, 17 % were positive for the PAs monitored, and their total PA contents ranged from 0.6 to 17.6 μg kg−1. In all of the samples, the contribution from the PANOs appeared to be negligible. The total PA contents found in the Veneto honey samples never exceeded the limit of 0.42 μg per day for an individual weighing 60 kg, established by the German Federal Institute of Risk Assessment (BfR) in 2011. These preliminary results provide useful advice to beekeepers for finding the most suitable location for beehives to achieve a substantial reduction of the PAs in honey.

Liquid Chromatography Tandem Mass Spectrometry Detection of Targeted Pyrrolizidine Alkaloids in Honeys Purchased within Ireland

Pyrrolizidine alkaloids (PAs) are naturally occurring plant toxins which can contaminate foods such as honey. Due to this emerging health and food safety risk, there is an increasing need to establish high sample throughput detection methods which are sensitive, selective and robust for PAs. A sensitive and comprehensive method was developed to determine ten PAs and four PA-N-oxides (PANOs) in honey using liquid chromatography-electrospray ionisation tandem mass spectrometry. Target compounds were detected and quantified using mass spectrometry in dynamic multiple reaction monitoring mode (dMRM). The samples were pre-concentrated using a polymeric strong cation exchange (SCX) solid-phase extraction (SPE) which allowed simultaneous screening of PAs and PANOs in honey (87 % mean recovery ± 9 %). The method was validated for selectivity, taking into consideration the matrix effects, specificity, linearity, accuracy and precision. Good linear calibrations were obtained for all ten PAs and four PANOs in spiked honey samples (3.6–357.1 μg L−1; R2 ≥ 0.995). Acceptable inter-day repeatability was achieved for the target analytes in honey with % RSD values (n = 17) less than 8 %. Limits of detection (LOD) and limits of quantitation (LOQ) were achieved with spiked PA and PANO samples, giving an average LOD of 1.0 μg kg−1 and LOQ of 3.4 μg kg−1. This method was successfully applied to 150 honeys purchased within Ireland between the years 2009 and 2011. The results show that PA contamination of honey is significant and comparative to other European studies, with 23 % of the samples testing positive for PA toxins in the range of 2.9 to 545.5 μg kg−1.

Easy and rapid method for the quantitative determination of pyrrolizidine alkaloids in honey by ultra performance liquid chromatography-mass spectrometry: An evaluation in commercial honey

Pyrrolizidine alkaloids (PAs) are toxins biosynthesised by plants and they are known to be present in approximately 6000 plant species, about 3% of all flowering plants. PAs are probably the most widely distributed natural toxins and represent a potential risk to human health, since poisoning caused by these toxins is associated with acute and chronic liver damage and may lead to death. One of the most common sources of PAs exposure in humans is honey consumption. We have developed a quick and easy method to quantify nine different PAs (echimidine, heliotrine, intermedine, lycopsamine, lasiocarpine, retrorsine, seneciphylline, senecionine, senkirkine) in honey based on QuEChERS sample extraction and ultra fast liquid chromatography coupled with mass spectrometry detection. We performed a validation study of the method and it resulted in good precision and accuracy, high recoveries, and good linear calibrations. The limit of detection ranged from 0.021 to 1.39 μg Kg−1 and the limit of quantification from 0.081 to 4.35 μg Kg−1. This new approach was applied to the quantification of PAs in retail honeys purchased in local supermarkets, classified by their country of origin: Italian honeys, blends of honey of European countries and blends of honey of European and non-European countries. The concentrations detected ranged from 1 to 169 μg PAs/kg−1 with higher concentrations in blends of European and non-European honeys. This study reveals that many samples tested would exceed the tolerable daily intake suggested for these substances and they could be a hazard to human health.

Pyrrolizidine alkaloids: their occurrence in Spanish honey collected from purple viper’s bugloss (Echium spp.)

The incidence and concentration of pyrrolizidine alkaloids (PAs) from Echium spp. plant have been defined in 103 Spanish honey samples. Each sample was examined to determine total pollen content, the percentage of Echium spp. pollen, and simultaneous measurements of PAs and their N-oxides concentrations by the HPLC-ESI/MS method to identify the potential origin of PAs in honey. PAs were found in 94.2% of the raw honey samples analysed, in the range of 1–237 µg kg−1 (average concentration = 48 µg kg−1). The PA pattern was clearly dominated by echimidine, lycopsamine and their N-oxides, representing the 97.8% of total ∑PAs, and only echimidine and echimidine-N-oxide surpassed the 87% of total ∑PA content. Others PAs, seneciphylline and heliotrine-N-oxide, appear to be reported in a lower incidence and concentration (average of 3 and 1 µg kg−1, respectively). The Pearson Chi-squared test (p ≤ 0.01) confirms the non-correspondence between pollen plants and PA content. This study was also realised to generate a dataset in order to evaluate the potential risk of Spanish honeys containing PA plants belonging to the genera Echium.