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The market demand for herbal dietary supplements is rapidly growing and such products are becoming more common and accessible to consumers. However, the knowledge about their safety remains incomplete. Herbal dietary supplements are one of the food groups that can contribute significantly to human health concerns arising from chronic exposure to pyrrolizidine alkaloids and mycotoxins. This study aimed to simultaneously determine 79 natural contaminants, including mycotoxins, as well as pyrrolizidine and tropane alkaloids in herbal dietary supplements in one analytical run. Exposure assessment and human health risks were assessed for all compounds included in this study. The total concentration of naturally occurring contaminants in herbal dietary supplements reached 5.3 mg kg−1 and the most frequently detected mycotoxins were tentoxin and alternariol monomethyl ether. The latter was detected with the highest frequency, reaching concentrations up to 2.5 mg kg−1. The obtained results indicate a potential risk to public health related to herbal dietary supplement consumption. [ABSTRACT FROM AUTHOR]

1,2-Dehydro-pyrrolizidine alkaloids (PA), their corresponding N-oxides (PANO) and tropane alkaloids (TA), are toxic plant metabolites. If plant material, containing these toxins, is present in the feed of dairy cows these toxins can be transferred into milk. Here, milk was sampled directly from dairy farms in the German federal states of Bavaria and Schleswig-Holstein in 2020–2022 in order to investigate a possible contamination of milk at the production stage. In total, 228 milk samples were analysed for 54 PA/PANO and two TA by a sensitive LC–ESI-MS/MS method. In addition, a subset of milk samples (n = 85) was independently analysed for TA by a cooperating laboratory for verification. PA/PANO were found in 26 samples (11%) with a low median sum content of the contaminated samples of 0.024 µg/L. The highest level of contamination was 5.6 µg/L. Senecionine-, lycopsamine- and heliotrine-type PA/PANO were detected. In four samples (1.8%), atropine was determined up to 0.066 µg/L. The toxin levels in the milk samples hardly contributed to the total daily exposure. These data are first-time results on contamination rates and levels occurring in milk from individual dairy farms, based on a large sample number. [ABSTRACT FROM AUTHOR]

Pyrrolizidine alkaloids (PAs) are one of the largest distributed classes of toxins in nature. They have a wide range of toxicity, such as hepatotoxicity, pulmonary toxicity, neuronal toxicity, and carcinogenesis. Yet, biological targets responsible for these effects are not well addressed. Using methods of computational biology for target identification, we tested more than 200 PAs. We used a machine-learning approach that applies structural similarity for target identification, ChemMapper, and SwissTargetPrediction. The predicted targets with high probabilities were muscarinic acetylcholine receptor M1. The predicted interactions between these two targets and PAs were further studied by molecular docking-based binding energies using AutoDock and VinaLC, which revealed good binding affinities. The PAs are bound to the same binding pocket as pirenzepine, a known M1 antagonist. These results were confirmed by in vitro assays showing that PAs increased the levels of intracellular calcium. We conclude that PAs are potential acetylcholine receptor M1 antagonists. This elucidates for the first time the serious neuro-oncological toxicities exerted by PA consumption. [ABSTRACT FROM AUTHOR]

Heterocyclic organic compounds named pyrrolizidine alkaloids (PAs) belong to a group of alkaloids and are synthesized by either plants or microorganisms. Therefore, they are naturally occurring secondary metabolites. They are found in species applied in the pharmaceutical and food industries, thus a thorough knowledge of their pharmacological properties and toxicology to humans is of great importance for their further safe employment. This review is original because it synthesizes knowledge of plant and microbial PAs, which is unusual in the scientific literature. We have focused on the Boraginaceae family, which is unique due to the exceptional richness and diversity of its PAs in plant species. We have also presented the microbial sources of PAs, both from fungi and bacteria. The structure and metabolism of PAs have been discussed. Our main aim was to summarize the effects of PAs on humans, including both negative, toxic ones, mainly concerning hepatotoxicity and carcinogenicity, as well as potentially positive ones for pharmacological and medical applications. We have collected the results of studies on the anticancer activity of PAs from plant and microbial sources (mainly Streptomyces strains) and on the antimicrobial activity of PAs on different strains of microorganisms (bacteria and fungi). Finally, we have suggested potential applications and future perspectives. [ABSTRACT FROM AUTHOR]

Gelsemium elegans (G.elegans) is a plant of the Loganiaceae family, known for its indole alkaloids, including gelsemine, koumine, and gelsenicine. Gelsemine and koumine are well-studied active alkaloids with low toxicity, valued for their anti-anxiety and analgesic properties. However, gelsenicine, another important alkaloid, remains underexplored due to its high toxicity. This study focuses on evaluating the analgesic properties of gelsenicine and comparing them with gelsemine and koumine. The results indicate that all three alkaloids exhibit robust analgesic properties, with gelsemine, koumine, and gelsenicine showing ED 50 values of 0.82 mg/kg, 0.60 mg/kg, and 8.43 μg/kg, respectively, as assessed by the hot plate method. Notably, the therapeutic dose of gelsenicine was significantly lower than its toxic dose (LD 50 = 0.185 mg/kg). The study also investigated the mechanism of action by analyzing the expression levels of GlyRα3 and Gephyrin. The PGE 2 model group showed decreased expression levels of GlyRα3 and Gephyrin, while groups treated with gelsemine, koumine, and gelsenicine were able to reverse this decrease. These results suggest that gelsenicine effectively alleviates PGE 2 -induced hyperalgesia by upregulating the expression of GlyRα3 and Gephyrin, which are key targets of the Gly receptor pathway. • This study explored the analgesic mechanism of gelsenicine for the first time. • Gelsenicine can significantly relieve the hypersensitivity pain caused by PGE 2. • Gelsenicine did not cause pathological damage to the mouse's spinal cord. • Gelsenicine has the best analgesic effect among the G.elegans alkaloids. [ABSTRACT FROM AUTHOR]

Background: Plant-derived pyrrolizidine alkaloids (PAs) in feed cause metabolic disturbances in farm animals resulting in high economic losses worldwide. The molecular pathways affected by these PAs in cells and tissues are not yet fully understood. The objective of the study was to examine the dose-dependent effects of orally applied PAs derived from tansy ragwort in midlactation dairy cows. Methods: Twenty Holstein dairy cows were treated with target exposures of 0, 0.47, 0.95 and 1.91 mg of total PA/kg of body weight/d in control, PA1, PA2 and PA3, respectively, for 28 days. Liver tissue biopsy and plasma and milk samples were taken at day 28 of treatment to assess changes in metabolic pathways. A targeted metabolomics approach was performed to detect the metabolite profiles in all compartments. Results: The PA-affected metabolite profiling in liver tissue, plasma and milk revealed changes in three substrate classes: acylcarnitines (ACs), phosphatidylcholines (PCs) and sphingomyelins (SMs). In addition, in the plasma, amino acid concentrations were affected by PA exposure. Conclusions: PA exposure disturbed liver metabolism at many sites, especially devastating pathways related to energy metabolism and to amino acid utilization, most likely based on mitochondrial oxidative stress. The effects on the milk metabolite profile may have consequences for milk quality. [ABSTRACT FROM AUTHOR]

Pyrrolizidine alkaloids (PAs) are noted for their hepatotoxic, genotoxic, and carcinogenic effects in animals and humans following metabolic activation in the liver. In this study, herbal supplements sold in Ghana for sexual improvement were analysed for the presence of 64 PAs using LC-MS/MS analysis. Up to 17 different PAs were identified in 19 out of the 37 samples analysed. The sum of PAs in samples ranged from 5 to 3204 μg kg−1. Since the PA content in the herbal medicinal preparations was generally lower than in honey samples, their presence was mainly attributed to cross-contamination. The observed levels would result in estimated daily intakes from 0.01 to 12 μg per day or 0.0002 to 0.2 μg kg−1 bw day−1 for a person weighing 70 kg. The margins of exposure ranged from 1200 to 1,400,000 with eight samples showing values below 10,000, thus indicating a health concern. [ABSTRACT FROM AUTHOR]

SUMMARY: Identification of unknown metabolites and their biosynthetic genes is an active research area in plant specialized metabolism. By following a gene–metabolite association from a genome‐wide association study of Arabidopsis stem metabolites, we report a previously unknown metabolite, 2‐hydroxy‐2‐(1‐hydroxyethyl)pentanoic acid glucoside, and demonstrated that UGT76F1 is responsible for its production in Arabidopsis. The chemical structure of the glucoside was determined by a series of analyses, including tandem MS, acid and base hydrolysis, and NMR spectrometry. T‐DNA knockout mutants of UGT76F1 are devoid of the glucoside but accumulate increased levels of the aglycone. 2‐hydroxy‐2‐(1‐hydroxyethyl)pentanoic acid is structurally related to the C7‐necic acid component of lycopsamine‐type pyrrolizidine alkaloids such as trachelantic acid and viridifloric acid. Feeding norvaline greatly enhances the accumulation of 2‐hydroxy‐2‐(1‐hydroxyethyl)pentanoic acid glucoside in wild‐type but not the UGT76F1 knockout mutant plants, providing evidence for an orthologous C7‐necic acid biosynthetic pathway in Arabidopsis despite the apparent lack of pyrrolizidine alkaloids. Significance Statement: The present study reports a previously unknown metabolite and the function of UGT76F1 in Arabidopsis. This metabolite is structurally related to the C7‐necic acid moiety of certain pyrrolizidine alkaloids, suggesting that necic acid biosynthesis may have a wider taxonomic distribution in non‐alkaloid‐containing species. [ABSTRACT FROM AUTHOR]

A new prenylated indole alkaloid—Penicimutamide C N-oxide (1), a new alkaloid penicimutamine A (2), along with six known alkaloids were isolated from an endophytic fungus Pallidocercospora crystallina. A simple and accurate method was used to determine the N-O bond in the N-oxide group of 1. By using a β-cell ablation diabetic zebrafish model, compounds 1, 3, 5, 6 and 8 showed significantly hypoglycemic activities under the concentration of 10 μM. Further studies revealed that compounds 1 and 8 lowered the glucose level through promoting glucose uptake in zebrafish. In addition, all eight compounds showed no acute toxicity, teratogenicity, nor vascular toxicity in zebrafish under the concentrations range from 2.5 μΜ to 40 μM. Importantly, these results provide new lead compounds for the development of antidiabetes strategies. [ABSTRACT FROM AUTHOR]

Pyrrolizidine alkaloids (PAs) occur as contaminants in plant-based foods and herbal medicines. Following metabolic activation by cytochrome P450 (CYP) enzymes, PAs induce DNA damage, hepatotoxicity and can cause liver cancer in rodents. There is ample evidence that the chemical structure of PAs determines their toxicity. However, more quantitative genotoxicity data are required, particularly in primary human hepatocytes (PHH). Here, the genotoxicity of eleven structurally different PAs was investigated in human HepG2 liver cells with CYP3A4 overexpression and PHH using an in vitro test battery. Furthermore, the data were subject to benchmark dose (BMD) modeling to derive the genotoxic potency of individual PAs. The cytotoxicity was initially determined in HepG2-CYP3A4 cells, revealing a clear structure–toxicity relationship for the PAs. Importantly, experiments in PHH confirmed the structure-dependent toxicity and cytotoxic potency ranking of the tested PAs. The genotoxicity markers γH2AX and p53 as well as the alkaline Comet assay consistently demonstrated a structure-dependent genotoxicity of PAs in HepG2-CYP3A4 cells, correlating well with their cytotoxic potency. BMD modeling yielded BMD values in the range of 0.1–10 µM for most cyclic and open diesters, followed by the monoesters. While retrorsine showed the highest genotoxic potency, monocrotaline and lycopsamine displayed the lowest genotoxicity. Finally, experiments in PHH corroborated the genotoxic potency ranking, and revealed genotoxic effects even in the absence of detectable cytotoxicity. In conclusion, our findings strongly support the concept of grouping PAs into potency classes and help to pave the way for a broader acceptance of relative potency factors in risk assessment. [ABSTRACT FROM AUTHOR]

Pyrrolizidine alkaloids (PAs) are widely distributed natural toxins and have been extensively studied for their hepatotoxicity. However, PA-induced pulmonary toxicity remains less studied regarding the initiating mechanism and treatment approaches. Our previous study demonstrated the formation of pyrrole–hemoglobin adducts after PA exposure in vivo, which is suspected to affect the oxygen-carrying capacity of erythrocytes [red blood cells (RBCs)] consequently. The present study aimed to investigate the effects of PAs on the oxygen-carrying capacity of RBCs and the potential of targeting RBC-mediated hypoxia to alleviate PA-induced lung injury. First, rats were treated with retrorsine (RTS) or monocrotaline (MCT) intravenously at 0.2 mmol/kg. The results of Raman spectrometry analysis on blood samples revealed both RTS and MCT significantly reduced the oxygen-carrying capacity of RBCs. Further, MCT (0.2 mmol/kg) was orally given to the rats with or without pretreatment with two doses of erythropoietin (Epo, 500 IU/kg/dose every other day), an RBC-stimulating agent. Biochemical and histological results showed pretreatment with Epo effectively reduced the cardiopulmonary toxicity induced by MCT. These findings provide the first evidence that adduction on hemoglobin, and the resulting RBC damage and impaired oxygen-carrying capacity, are the major initiating mechanism underlying PA-induced pulmonary arterial hypertension (PAH), while targeting the RBC damage is a potential therapeutic approach for PA-induced lung injury. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Three new compounds, the silphiperfolanol angelate ester umutagarananol (1), the macrocyclic pyrrolizidine alkaloids umutagarinine A and B (2–3), and five known secondary metabolites (4–8) were isolated from the CH2Cl2−MeOH (1 : 1) extract of the roots and the stem bark of Solanecio mannii (Hook. f.) (Asteraceae). The isolated compounds were characterized by NMR and IR spectroscopic, and mass spectrometric analyses, whereas the relative stereochemistry of 4 was established by NAMFIS‐based combined computational and solution NMR analysis. Synthetic modification of 5 provided two new compounds, 2‐angeloyloxy‐4,8‐epoxypresilphiperfolane (9) and 2‐angeloyloxy‐4,8‐epoxypresilphi‐perfolane (10). The crude extracts and the isolated constituents showed weak antibacterial activities (EC50 0.7–13.3 mM) against the Gram‐negative Escherichia coli and the Gram‐positive Bacillus subtilis. Compounds 2, 3 and 4 exhibited strong cytotoxicity against MCF‐7 human breast cancer cells, with EC50 values of 35.6, 21.7 and 12.5 μM, respectively. [ABSTRACT FROM AUTHOR]

Spices, herbs, and tea have been used for dietary purposes since ancient times. Some of them may contain toxic natural plant toxins synthesized in plant secondary metabolism or because of co-harvesting or horizontal product transfer with other plants. This review highlights the main extraction and clean-up procedures developed for alkenylbenzenes, pyrrolizidine and tropane alkaloids from plant-derived food products published between 2010 and 2020. Analytical methods are discussed, paying attention to those based on chromatographic separation coupled with classical or mass spectrometry detectors. Finally, an overview of the occurrence of these compounds in the studied matrices is performed. [ABSTRACT FROM AUTHOR]

Skin cancer has high rates of mortality and therapeutic failure. In this study, to develop a multi-agent strategy for skin cancer management, the selective cytotoxicity of several alkaloid fractions and pure alkaloids isolated from Amaryllidaceae species was evaluated in melanoma cells. In addition, UVB-stimulated keratinocytes (HaCaT) were exposed to seven alkaloid fractions characterized by GC-MS, and the production of intracellular reactive oxygen species (ROS) and IL-6, were measured to evaluate their photoprotection effects. The Eucharis caucana (bulb) alkaloid fraction (20 μg/ml) had a clear effect on the viability of melanoma cells, reducing it by 45.7% without affecting healthy keratinocytes. This alkaloid fraction and tazettine (both at 2.5 μg/ml) suppressed UVB-induced ROS production by 31.6% and 29.4%, respectively. The highest anti-inflammatory potential was shown by the Zephyranthes carinata (bulb) alkaloid fraction (10 μg/ml), which reduced IL-6 production by 90.8%. According to the chemometric analysis, lycoramine and tazettine had a photoprotective effect on the UVB-exposed HaCaT cells, attenuating the production of ROS and IL-6. These results suggest that Amaryllidaceae alkaloids have photoprotective and therapeutic potential in skin cancer management, especially at low concentrations. [ABSTRACT FROM AUTHOR]

Background: Studies on pyrrolizidine alkaloid (PA) contamination in honey produced in China are scarce. Previously reported HPLC-MS/MSmethods for the determination of PAs in honey often suffer from insufficient separation and uncertainties in PA isomers. Objective: To develop and validate an Ultra-HPLC (UHPLC)-MS/MS method for baseline separation of PA isomers towards precise determination of 32 PAs in Chinese wild honey. Methods: PAs were extracted from honey samples and separated on an ACQUITY BEH C18 (2.1mm 100mm, 1.7 lm) column with (A) 0.1% formic acid aqueous solution containing 5mM ammonium acetate and (B) methanol as mobile phase. The column temperature was maintained at 30 °C, and flow rate was 0.3 mL/min. Detection was performed by tandem mass spectrometry. The total run time was reduced to 18 min. Results: Thirty-one of 32 PAs were baseline separated efficiently within 18 min. The LOD and LOQ were 0.06-0.25 lg/kg and 0.22-0.82 lg/kg, respectively, except for that of clivorine, for which LOD and LOQ were 2.03 and 6.78 lg/kg, respectively. The average recoveries ranged between 66.3 and 95.1% and the average RSDs were 3.2 to 8%. The established method was used to analyze PAs in 22 types of Chinese wild honey, and the predominant PAs found in these honey samples were intermedine and lycopsamine. Conclusion: A high-throughput method for the determination of isomeric PAs in honey was developed and validated. Five of the 22 types of Chinese wild honey were contaminated with PAs concentrations of 2.2-207.0 lg/kg. Highlights: A new method capable of monitoring more PAs and providing better separation than previously reported protocols for the determination of multiclass PAs in honey is established. [ABSTRACT FROM AUTHOR]

Objective: The aim of this study was to identify and determine the content of toxic components(diester‑type alkaloids) in Aconitum brachypodum, providing scientific support for the safe clinical use of this medicinal herb and offering a basis for quality control. Methods: Acidic water was used to extract the alkaloids from Aconitum brachypodum, which were then extracted with petroleum ether. Toxic components were separated and extracted with chloroform from the acid water, with the phenolic acidic fractions absorbed by alkaline oxidized alumina. The toxic components were identified by thin‑layer chromatography (TLC), and the content was measured by ultraviolet (UV)–visible spectrophotometry. Results: A method for special thin‑layer identification of toxic components and general determination of total alkaloid content in Aconitum brachypodum was established. The mean content of toxic diterpenoid alkaloids in Aconitum brachypodum cultivated in the Dongchuan district of Kunming was approximately 0.30%. Conclusion: Selective extraction of toxic alkaloids in Aconitum brachypodum by chemical methods, identification by TLC, and content determination by UV–visible spectrophotometry can control the toxicity of this herb, guide production, and ensure clinical safety. [ABSTRACT FROM AUTHOR]

In this paper, I review the effects of the diet of ladybirds on chemical defence in this group of beetles. The tendency to reflex bleed and the diversity of autogenously produced alkaloids in different taxa may be evolutionarily related to diet and the likelihood of food limitation. Within predatory species, both prey quantity and quality have been shown to affect autogenous alkaloid production. A few ladybird predators have been suggested to adaptively sequester toxins from their prey for their own defence. However, in most cases the evidence for this is limited, with questions remaining about the costs of accumulated toxins and their defensive value, especially over and above pre-existing autogenous defence. Only a single case (Hyperaspis trifurcata and carminic acid) is well supported. In the case of ladybird predators acquiring pyrrolizidine alkaloids from the ragwort aphid Aphis jacobaeae, I show that toxin accumulation is not very costly and the aphid is even an essential prey for some ladybirds. However, the defensive value of pyrrolizidine alkaloids to ladybirds is still not investigated. Intraspecific diversity in autogenous chemical defence could be reinforced further if chemical protection is conferred via sequestered chemicals. However, to understand better how ladybird diet and chemical defence interact, we need a clearer grasp of how the defensive chemicals of food are resisted or tolerated by ladybirds. [ABSTRACT FROM AUTHOR]

Metabolic oxidation of pyrrolizidine alkaloids (PAs) from herbal and dietary supplements by cytochrome P450 produces dehydro‐PAs (DHPs), which leads to toxicities. A highly reactive cation species generated from the active pyrrole ring of DHPs readily reacts with various cellular components, causing hepatotoxicity and cytotoxicity. Inspired by PA‐induced hepatic damage, we developed a therapeutic approach based on a cyclization precursor that can be transformed into a synthetic DHP under physiological conditions through gold‐catalyzed 5‐endo‐dig cyclization using a gold‐based artificial metalloenzyme (ArM) instead of through metabolic oxidation by cytochrome P450. In cell‐based assays, the synthesis of the DHP by a cancer‐targeting glycosylated gold‐based ArM substantially suppressed cell growth of the targeted cancer cells without causing cytotoxicity to untargeted cells, highlighting the potential of the strategy to be used therapeutically in vivo. [ABSTRACT FROM AUTHOR]

Metabolic oxidation of pyrrolizidine alkaloids (PAs) from herbal and dietary supplements by cytochrome P450 produces dehydro‐PAs (DHPs), which leads to toxicities. A highly reactive cation species generated from the active pyrrole ring of DHPs readily reacts with various cellular components, causing hepatotoxicity and cytotoxicity. Inspired by PA‐induced hepatic damage, we developed a therapeutic approach based on a cyclization precursor that can be transformed into a synthetic DHP under physiological conditions through gold‐catalyzed 5‐endo‐dig cyclization using a gold‐based artificial metalloenzyme (ArM) instead of through metabolic oxidation by cytochrome P450. In cell‐based assays, the synthesis of the DHP by a cancer‐targeting glycosylated gold‐based ArM substantially suppressed cell growth of the targeted cancer cells without causing cytotoxicity to untargeted cells, highlighting the potential of the strategy to be used therapeutically in vivo. [ABSTRACT FROM AUTHOR]

Insect herbivores have evolved a broad spectrum of adaptations in response to the diversity of chemical defences employed by plants. Here we focus on two species of New Guinean Asota and determine how these specialist moths deal with the leaf alkaloids of their fig (Ficus) hosts. As each focal Asota species is restricted to one of three chemically distinct species of Ficus, we also test whether these specialized interactions lead to similar alkaloid profiles in both Asota species. We reared Asota caterpillars on their respective Ficus hosts in natural conditions and analyzed the alkaloid profiles of leaf, frass, caterpillar, and adult moth samples using UHPLC–MS/MS analyses. We identified 43 alkaloids in our samples. Leaf alkaloids showed various fates. Some were excreted in frass or found in caterpillars and adult moths. We also found two apparently novel indole alkaloids—likely synthesized de novo by the moths or their microbiota—in both caterpillar and adult tissue but not in leaves or frass. Overall, alkaloids unique or largely restricted to insect tissue were shared across moth species despite feeding on different hosts. This indicates that a limited number of plant compounds have a direct ecological function that is conserved among the studied species. Our results provide evidence for the importance of phytochemistry and metabolic strategies in the formation of plant–insect interactions and food webs in general. Furthermore, we provide a new potential example of insects acquiring chemicals for their benefit in an ecologically relevant insect genus. [ABSTRACT FROM AUTHOR]

In this paper, I review the effects of the diet of ladybirds on chemical defence in this group of beetles. The tendency to refl ex bleed and the diversity of autogenously produced alkaloids in different taxa may be evolutionarily related to diet and the likelihood of food limitation. Within predatory species, both prey quantity and quality have been shown to affect autogenous alkaloid production. A few ladybird predators have been suggested to adaptively sequester toxins from their prey for their own defence. However, in most cases the evidence for this is limited, with questions remaining about the costs of accumulated toxins and their defensive value, especially over and above pre-existing autogenous defence. Only a single case (Hyperaspis trifurcata and carminic acid) is well supported. In the case of ladybird predators acquiring pyrrolizidine alkaloids from the ragwort aphid Aphis jacobaeae, I show that toxin accumulation is not very costly and the aphid is even an essential prey for some ladybirds. However, the defensive value of pyrrolizidine alkaloids to ladybirds is still not investigated. Intraspecifi c diversity in autogenous chemical defence could be reinforced further if chemical protection is conferred via sequestered chemicals. However, to understand better how ladybird diet and chemical defence interact, we need a clearer grasp of how the defensive chemicals of food are resisted or tolerated by ladybirds. [ABSTRACT FROM AUTHOR]

Pyrrolizidine alkaloids (PAs) are produced by various plant species and have been detected as contaminants in food and feed. Monitoring programmes should include PAs that are present in relevant matrices and that exhibit a high toxic potential. The aim of the present study was to use a bioassay-directed analysis approach to identify relevant PAs not yet included in monitoring programmes. To that end, extracts of Heliotropium europaeum and H. popovii were prepared and analysed with LC–MS/MS for the presence of 35 PAs included in monitoring programmes, as well as for genotoxic activity in the HepaRG/γH2AX assay. Europine, heliotrine and lasiocarpine were found to be the most abundant PAs. The extracts showed a higher γH2AX activity than related artificial mixtures of quantified known PAs, which might point to the presence of unknown toxic PAs. The H. europaeum extract was fractionated and γH2AX activities of individual fractions were determined. Fractions were further analysed applying LC–Orbitrap-MS analysis and Compound Discoverer software, identifying various candidate PAs responsible for the non-explained genotoxic activity. Altogether, the results obtained show that bioassay-directed analysis allows identification of candidate PAs that can be included in monitoring programmes. [ABSTRACT FROM AUTHOR]

A general method for the synthesis of pyrrolizidine derivatives using an intramolecular hydroaminomethylation protocol (HAM) under microwave (MW) dielectric heating is reported. Starting from a 3,4-bis(benzyloxy)-2-[(benzyloxy)methyl]-5-vinylpyrrolidine, MW-assisted intramolecular HAM in the presence of gaseous H2 and CO gave the natural alkaloid hyacinthacine A2 protected as benzyl ether. The same approach gave a lentiginosine analogue starting from the corresponding vinyl N-hydroxypyrrolidine. The nature of the reaction products and the yields were strongly influenced by the relative stereochemistry of the starting pyrrolidines, as well as by the catalyst/ligand employed. The use of ethanol as a solvent provides environmentally friendly conditions, while the ligand/catalyst system can be recovered by separating the alkaloid product with an SCX column and recycling the ethanolic solution. HAM worked up to three times with the recycled catalyst solution without any significant impact on yield. [ABSTRACT FROM AUTHOR]

[Display omitted] • Cutting-edge mass spectrometry as the cornerstone for pyrrolizidine alkaloid analysis in complex samples. • Innovative analytical strategies reshaping PAs analysis are presented. • Different applications of PAs containing related samples has been summarized. Pyrrolizidine alkaloids (PAs) in food and natural preparations have received widespread attention due to their hepatotoxicity, genotoxicity, and embryotoxicity. Mass spectrometry (MS), as a high resolution, high sensitive, and high throughput detection tool, has been the most commonly used technique for the determination of PAs. The continuous advancement of new technologies, methods, and strategies in the field of MS has contributed to the improvement of the analytical efficiency and methodological enhancement of PAs. This paper provides an overview of the structure, toxicity properties and commonly employed analytical methods, focusing on the concepts, advances, and novel techniques and applications of MS-based methods for the analysis of PAs. Additionally, the remaining challenges, future perspectives, and trends for PA detection are discussed. This review provides a reference for toxicological studies of PAs, content monitoring, and the establishment of quality control and safety standards for herbal and food products. [ABSTRACT FROM AUTHOR]

[Display omitted] • A total concentration of 41.4 ∼ 342.1 ng/L PAs in treated drinking water was discovered for the first time. • Up to 97 % of heliotrine and N-oxide were degraded by UV/persulfate in 30 min. • Based on steady-state kinetic models, effect of various influence factors were evaluated. • The EE/O calculations suggested UV/PDS was a cost-effective treatment for controlling PA contamination in actual applications. • Degradation pathways of heliotrine and N-oxide oxidated by sulfate radicals were proposed. Pyrrolizidine alkaloids (PAs), recognized as a group of toxic secondary metabolites, have raised growing concerns in recent years due to their potential high toxicity. However, studies on the degradation of PAs in drinking water treatments have yet to be conducted. Herein, the treatment of Heliotrine (HEL) and N-oxide (HELNO), two dominant PAs detected in the treated drinking water, are analyzed for the first time. The UV/peroxydisulfate (UV/PDS) process was demonstrated to be efficient in the degradation of PAs, achieving almost complete removal of HEL and HELNO in 30 min. SO 4 •− plays a dominant role in the system, with second-order rate constants of 2.3 × 109 M−1 s−1 and 1.0 × 109 M−1 s−1 for HEL and HELNO, respectively. Based on the steady-state kinetic models, the effect of influence factors, including PDS dosage, initial pollutant concentration, pH, dissolved organic matter (DOM), and chloride (Cl−), were evaluated. Acidic conditions were proven to be favorable for PA degradations, primarily contributed to the minimized quenching effect of OH− and phosphate on SO 4 •−. The inhibitory effect of DOM on radical quenching significantly overweighted the promotion effect of the generated excited triplet DOM (3DOM*), resulting in a diminished degradation efficiency. The pronounced inhibition of Cl− could be attributed to the conversion of SO 4 •− to OH•, involving the formation of reactive chlorine species. The UV/PDS treatment was suggested economical in the removal of PAs as a post-filtration and before-chlorination treatment through electrical energy per order (EE/O) calculation. Finally, reasonable degradation pathways of HEL and HELNO reacted with SO 4 •− were proposed, involving the initial one-electron oxidation of HEL/HELNO by SO 4 •− radical, and further reactions (e.g. , hydroxylation, pyrrolidine ring-cleavage and self-coupling) of the formed N-centered cation radicals. [ABSTRACT FROM AUTHOR]

Pyrrolizidine alkaloids (PA) are comprised of a family of hundreds of metabolites, produced by plants as a mechanism to protect against herbivory. Upon ingestion and metabolism, dehydropyrrolizidine alkaloids are formed, which are known to generate DNA adducts and subsequently double-strand DNA breaks. Within the liver, the most sensitive cell type to PA exposure is the sinusoidal endothelial cell, as evidenced by the generation of veno-occlusive disease in the human population. PAs are a common crop contaminant and have been regulated by some agencies, using the precautionary principle; each equally potent and genotoxic. Therefore, as a proof of principle we have established a human in vitro coculture model system, utilizing the metabolically active HepaRG hepatocyte and the SK-Hep-1 endothelial cell, to determine differential potencies of different PAs commonly found in crops and food products, notably cell death, targeting of endothelial cells, and genotoxicity comparing the micronucleus assay versus γH2AX assay. Our results demonstrate differential potencies of the PAs used, which encompass three esterification states (monoester, cyclic diester, and open-chain diester). The results suggest that a more nuanced approach to the regulation of PAs may be more appropriate in the regulatory decision-making process. • The presented data demonstrate a novel hepatic coculture system. • PAs spanning three different esterification states have differential potencies. • The data suggests the need for nuance in the regulation of PA contamination. [ABSTRACT FROM AUTHOR]

In this study, the microwave‐assisted processing of Sesamum indicum leaves was intensified to predict the total alkaloid content via Taguchi orthogonal design and neural network model. Under the optimum microwave condition, the maximized alkaloid content was estimated to be 15.40 (mg/g) % using irradiation time (A) of 60 sec, microwave power (B) of 300 W, oven temperature (C) of 60°C, the mass ratio (D) of 12.5 g/ml, and solvent concentration (E) of 80%. The significant effects of each microwave extraction parameter declined in the order listed: C > B > A > D > E which indicated a 31 and 29% contribution of microwave power and oven temperature, respectively. Moreover, higher coefficients of determination (R2 = 0.9999), and a decreased mean square error (MSE) of 2.69E‐07 suggest good accuracy in predicting total bioactive alkaloid recovery, as proven by cross‐validation trials. Under these microwave conditions, a total of 115 alkaloids were tentatively identified with lindelofine (m/z = 308.18) and supinin (m/z = 306.17) being the most abundant pyrrolizidine alkaloids. Novelty impact statement: Although many researchers reported the total alkaloids recoveries from different parts of Sesame plant; the process intensification of microwave processing from leafy parts using Taguchi design and ANN approach have not been investigated. This study established an optimum condition for the total recovery of alkaloid content from S. indicum using orthogonal optimization methodology and artificial neural network [ABSTRACT FROM AUTHOR]

Lipid droplet accumulation (LDA) in hepatocytes is the initial stage of nonalcoholic fatty liver disease (NAFLD). In the search for natural compounds for the prevention of NAFLD, a series of β-carboline alkaloid derivatives, inspired by flazin and its derivative, newly identified in Crassostrea gigas Thunberg. extracts, were examined for LDA inhibition (LDAI) activity in oleic acid–loaded hepatocytes (HepG2). Eight compounds with a piperidine or pyridine C-ring were chemically synthesized (1–8). Among them, compounds 2 and 4 (flazin) with a carboxy group at C-3 and furfuryl alcohol moiety at C-1 showed low cytotoxicity and they exhibited significant LDAI activity. Compound 2 with piperidine C-ring was identified for the first time in C. gigas extract, and ameliorated the lipid accumulation with the LDAI value of 25.4%. Active compounds 2 and 4 significantly inhibited triacylglycerol species accumulation in cells. These compounds upregulated ATGL and downregulated SREBP1, FASN, and SCD1 genes, suggesting that they activated lipolysis and suppressed lipogenesis, respectively. These results suggest that β-carboline alkaloids, especially compounds 2 and 4, might be potentially useful for preventing NAFLD. [ABSTRACT FROM AUTHOR]

Pyrrolizidine alkaloid (PA) producing plants like Senecio jacobaea or Senecio vernalis are undesirable in fields for forage production, since PA are toxic to animals and humans. Previous studies have shown that ensiling can decrease the PA content in forages; however, no direct comparison of diverse PA from different Senecio spp. under various ensiling conditions has been made. Therefore, it was hypothesised that individual PA might react differently to ensiling, and silage inoculation with Lactobacillus will affect PA degradation because of a quick drop in pH, contrastingly to poor silage qualities resulting from contamination with soil. Laboratory scale grass silages were prepared in a multifactorial design with two levels of dry matter contents, four ensiling treatments and two storage durations (10 and 90 d). For each combination, four replicates were prepared individually. Ensiling treatments were (1) 10 ml water per kg fresh matter as control (CON), (2) 10 ml heterofermentative Lactobacillus buchneri strain LN4637 at 3 · 105 cfu/kg fresh matter plus 25 g molasses/kg fresh matter (LBHE), (3) 10 ml homofermentative lactobacilli at 3 · 105 cfu/kg fresh matter plus 25 g molasses/kg fresh matter (LBHO) and (4) 10 g soil/kg fresh matter (SOIL). Treatments affected formation of fermentation acids. Acetic acid was highest with treatment LBHE, and butyric acid was highest with treatment SOIL. All ensiling treatments effectively reduced total PA content by degrading the PA N-oxide (PANO) fraction. In parallel, though, the fraction of the tertiary base forms increased by around one-tenth of the original PANO content. Contents of jaconine and senkirkine were higher after ensiling than before, with regards to the sum of PA and PANO for jaconine, indicating higher stability or new formation through degradation of other PA. Overall, ensiling offers opportunities to decrease the PA-PANO content in feed and therefore lowers the risk of intoxication by Senecio in livestock. [ABSTRACT FROM AUTHOR]

Plants produce many secondary metabolites showing considerable inter‐ and intraspecific diversity of concentration and composition as a strategy to cope with environmental stresses. The evolution of plant defenses against herbivores and pathogens can be unraveled by understanding the mechanisms underlying chemical diversity. Pyrrolizidine alkaloids are a class of secondary metabolites with high diversity. We performed a qualitative and quantitative analysis of 80 pyrrolizidine alkaloids with liquid chromatography‐tandem mass spectrometry of leaves from 17 Jacobaea species including one to three populations per species with 4–10 individuals per population grown under controlled conditions in a climate chamber. We observed large inter‐ and intraspecific variation in pyrrolizidine alkaloid concentration and composition, which were both species‐specific. Furthermore, we sequenced 11 plastid and three nuclear regions to reconstruct the phylogeny of the 17 Jacobaea species. Ancestral state reconstruction at the species level showed mainly random distributions of individual pyrrolizidine alkaloids. We found little evidence for phylogenetic signals, as nine out of 80 pyrrolizidine alkaloids showed a significant phylogenetic signal for Pagel's λ statistics only, whereas no significance was detected for Blomberg's K measure. We speculate that this high pyrrolizidine alkaloid diversity is the result of the upregulation and downregulation of specific pyrrolizidine alkaloids depending on ecological needs rather than gains and losses of particular pyrrolizidine alkaloid biosynthesis genes during evolution. [ABSTRACT FROM AUTHOR]

Plants are the cradle of the traditional medicine system, assuaging human or animal diseases, and promoting health for thousands of years. However, many plant-derived medicines contain toxic alkaloids of varying degrees of toxicity that pose a direct or indirect threat to human and animal health through accidental ingestion, misuse of plant materials, or through the food chain. Thus, rapid, easy, and sensitive methods are needed to effectively screen these toxic alkaloids to guarantee the safety of plant-derived medicines. Antibodies, due to their inherent specificity and high affinity, have been used as a variety of analytical tools and techniques. This review describes the antigen synthesis and antibody preparation of the common toxic alkaloids in plant-derived medicines and discusses the advances of antibody-based immunoassays in the screening and detection of toxic alkaloids in plants or other related matrices. Finally, the limitations and prospects of immunoassays for toxic alkaloids are discussed. [ABSTRACT FROM AUTHOR]

Pyrrolizidine alkaloids (PAs) are phytotoxins widely present in various natural products and foodstuffs. The present study aims to investigate the effects of fasting on PA-induced hepatotoxicity and the underlying biochemical mechanisms. The results of hepatotoxic study showed that 15-h overnight fasting significantly exacerbated the hepatotoxicity of retrorsine (RTS, a representative toxic PA) in fasted rats compared to fed rats, as indicated by remarkably elevated plasma ALT and bilirubin levels and obvious liver histological changes. Further toxicokinetic studies revealed that fasting significantly enhanced cytochromes P450 enzymes (CYPs)-mediated metabolic activation of RTS leading to increased formation of pyrrole-protein adducts and thus decreased the in vivo exposure and excretion of both parent RTS and its N-oxide metabolite. Metabolic studies demonstrated that fasting induced enzyme activities of CYP1A2, CYP2B6 and CYP2E1 that participated in catalyzing RTS to its reactive pyrrolic metabolites. Moreover, fasting also dramatically decreased hepatic glutathione (GSH) content, which restricted the detoxification of GSH by neutralizing the reactive pyrrolic metabolite of RTS, further contributing to the enhanced hepatotoxicity. The present findings may have an impact on future PA toxicity tests with different dietary styles and/or risk assessment of metabolite-mediated toxins by considering the profound effects of fasting. [ABSTRACT FROM AUTHOR]

The new challenges in toxicology demand novel and innovative in vitro approaches for deriving points of departure (PODs) and determining the mode of action (MOA) of chemicals. Therefore, the aim of this original study was to couple in vitro studies with untargeted metabolomics to model the concentration-response of extra- and intracellular metabolome data on human HepaRG cells treated for 48 h with three pyrrolizidine alkaloids (PAs): heliotrine, retrorsine and lasiocarpine. Modeling revealed that the three PAs induced various monotonic and, importantly, biphasic curves of metabolite content. Based on unannotated metabolites, the endometabolome was more sensitive than the exometabolome in terms of metabolomic effects, and benchmark concentrations (BMCs) confirmed that lasiocarpine was the most hepatotoxic PA. Regarding its MOA, impairment of lipid metabolism was highlighted at a very low BMC (first quartile, 0.003 µM). Moreover, results confirmed that lasiocarpine targets bile acids, as well as amino acid and steroid metabolisms. Analysis of the endometabolome, based on coupling concentration-response and PODs, gave encouraging results for ranking toxins according to their hepatotoxic effects. Therefore, this novel approach is a promising tool for next-generation risk assessment, readily applicable to a broad range of compounds and toxic endpoints. [Display omitted] • PA effects on HepaRG cells were studied by concentration-response modelling and BMC. • The endometabolome was found to be more sensitive than the exometabolome. • LAS had the highest hepatotoxic potency, followed by HEL and RET. • The bell shape is the most frequent trend in response to LAS. • Lipids, bile acids and amino acids were especially affected by LAS. [ABSTRACT FROM AUTHOR]

Pyrrolizidine alkaloids (PAs) are secondary plant metabolites, and their 1,2-unsaturated derivatives, which contain the retronecine, heliotridine, or otonecine type of the necine base, have raised concern due to their ability to form hepatotoxic intermediates and exhibit serious toxic effects. Several hundred individual pyrrolizidine alkaloids and their N-oxides have been identified mostly using liquid chromatography coupled with mass spectrometry, although the number of available reference standards is limited. In this work, characteristic fragment ions and their abundance in the mass spectra of different PAs were used to reveal typical fragmentation patterns for various classes of PAs that can be further employed to distinguish monoesters (retronecine, heliotridine type), open chain diesters and macrocyclic diesters, and corresponding N-oxides. Fragment ions at m/z 120 and 138 were found in all types of PAs with a different relative abundance. Additional observation of fragment ions at m/z 94 and 156 was found to be typical for monoester PAs esterified at position C9 of the necin base, whereas fragment ions at m/z 111 and 172 were characteristic for monoester N-oxides. Fragment ions at m/z 180 and 220 were found to be typical for open chain diesters with esterification at C7 with acetic and angelic acid, respectively, whereas fragment ions at m/z 214 and 254 were characteristic for the respective N-oxides. For the 3'-acetyl PA monoester or open chain diester derivatives, characteristic fragment ions were observed after loss of the acetyl moiety ([M+H]+-60), whereas for macrocyclic diesters and their N-oxides, fragment ions due to the neutral loss of CO were found ([M+H]+-28). [ABSTRACT FROM AUTHOR]

Background: Pre-eclampsia (PE) is mainly attributed to the inflammation of trophoblast cells in pregnant women, which results in damage to the maternal organs and growth retardation of the fetus. Alkaloid leonurine (LNR) is a plant compound and has anti-inflammatory effects. Here we aimed to investigate the effects of LNR on human and mouse trophoblast cells and the underlying mechanisms. Methods: The levels of the inflammatory factors in trophoblast cells under lipopolysaccharides (LPS) stimulation were analyzed with ELISA. Western blot was employed to examine the protein expression. Trophoblast cells in Mammalian ste20-like kinase 1 (MST1-/-) or wild type (WT) mice were isolated to examine the expression of signal molecules in the nuclear factor-κB (NF-κB) pathway. Concentration-dependent activity of NF-κB was examined. The regulation of LNR and MST1 in MST1-/- trophoblast cells was studied as well. Results: Our data showed that LNR exhibited anti-inflammatory effects and suppressed the NF-κB signaling by inhibiting LPS-induced inflammation in trophoblast cells. LNR upregulated the expression of MST1, and the antiinflammatory role of LNR was greatly relieved in MST1-knockout trophoblast cells, although it displayed weak roles in NF-κB signaling. Conclusion: LNR exhibits anti-inflammatory effects on human and mouse trophoblast cells by upregulating MST1 in the NF-κB signal pathway. [ABSTRACT FROM AUTHOR]

1. Retrorsine (RTS) is a pyrrolizidine alkaloid (distributed in many medicinal plants) that has significant hepatotoxicity. Here, we aimed to determine the daily variations in RTS hepatotoxicity (chronotoxicity) in mice, and to investigate the role of metabolism in generating RTS chronotoxicity. 2. Acute toxicity and pharmacokinetic studies were performed with mice after RTS administration at different times of the day. Hepatotoxicity was assessed by measuring plasma ALT (alanine aminotransferase) and AST (aspartate aminotransferase) levels. mRNA and proteins were determined by qPCR and Western blotting, respectively. Time-dependent in vitro metabolism of RTS was assessed by using mouse liver microsomes. 3. We found that RTS toxicity was more severe in the dark phase (zeitgeber time 14 or ZT14 and ZT18) than in the light phase (ZT2 and ZT6). This chronotoxicity was associated with a dosing time difference in the systemic exposures of RTS and a pyrrolic ester metabolite (a cause of hepatotoxicity, measured by the levels of pyrrole-GSH conjugate and pyrrole-protein adducts due to a high chemical reactivity). Moreover, the CYP3A11 (a major enzyme for RTS bioactivation) inhibitor ketoconazole decreased the production of pyrrole-GSH conjugate and abrogated diurnal rhythm in RTS metabolism. In addition, E4bp4 (a circadian regulator of Cyp3a11) ablation abolished the rhythm of CYP3A11 expression and abrogated the dosing time-dependency of RTS toxicity. 4. In conclusion, RTS chronotoxicity in mice was attributed to time-varying hepatic metabolism regulated by the circadian clock. Our findings have implications for reducing pyrrolizidine alkaloid-induced toxicity via a chronotherapeutic approach. [ABSTRACT FROM AUTHOR]

• Alkaloids were detected in the leaves of southern African biotype of C. odorata by Mayor's and Dragendorff's reagents. • The main alkaloids were two epimeric pyrrolizidine N -oxides rinderine and intermidine. • Alkaloids in the leaves varied significantly in sites with and without specialist herbivore P. insulata. • Thin-layer chromatography did not demonstrate differences in alkaloids in the roots collected from sites with and without P. insulata. • Gas Chromatography-Mass Spectrometry identified rinderine N -oxides and intermidine N -oxides in the roots of SAB C. odorata. • One directional proton nuclear magnetic resonance analysis was used to confirm the structures of rinderine and intermidine. Pyrrolizidine alkaloids (PAs) are amino alcohols, often esterified with mono- or dicarboxylic acids, found in several plant families, including the Asteraceae. Pyrrolizidine alkaloids are used for plant defence against generalist invertebrate herbivores. However, specialist herbivores that are able to sequester PAs from the host plant species derive a number of benefits from these defence compounds. This study investigated alkaloids and PAs from the leaves and roots of the southern African biotype (SAB) of Chromolaena odorata in different regions and habitats in South Africa, with and without the specialist herbivore Pareuchaetes insulata. Alkaloid N -oxides were initially detected in leaf samples by Mayor's and Dragendorff's reagents and later by thin-layer chromatography on root samples with detection by successive treatment with acetic anhydride and Ehrlich's reagent. Two pyrrolizidine alkaloids, rinderine and the stereoisomer intermidine, were isolated from the reduced root extract of the SAB C. odorata and identified by Gas Chromatography-Mass Spectrometry. The structures and configuration of the compounds were confirmed by chemical and spectroscopic methods, especially one-dimensional 1H Nuclear Magnetic Resonance analysis. Pyrrolizidine alkaloids are known to be used by arctiine moths to find their host plant and are sequestered for mating purposes, and furthermore, these compounds render these lepidopterans unpalatable to predators. This study is the first to detect the presence of alkaloids and pyrrolizidine alkaloids in the SAB C. odorata. [ABSTRACT FROM AUTHOR]

Pyrrolizidine alkaloids (PAs) and PA N-oxides are common phytotoxins produced by over 6000 plant species. Humans are frequently exposed to PAs via ingestion of PA-containing herbal products or PA-contaminated foods. PAs require metabolic activation to form pyrrole–protein adducts and pyrrole-DNA adducts which lead to cytotoxicity and genotoxicity. Individual PAs differ in their metabolic activation patterns, which may cause significant difference in toxic potency of different PAs. This review discusses the current knowledge and recent advances of metabolic pathways of different PAs, especially the metabolic activation and metabolism-mediated cytotoxicity and genotoxicity, and the risk evaluation methods of PA exposure. In addition, this review provides perspectives of precision toxicity assessment strategies and biomarker development for the risk control and translational investigations of human intoxication by PAs. [ABSTRACT FROM AUTHOR]

Pyrrolizidine alkaloids (PA) are toxic for horses. Not only herbal teas also compound feed products for equids have tested positive for PA contamination. Nutraceuticals for horses are used for their constitutional effects regarding different organ systems, for example the liver. Especially in nutraceuticals used for their hepatoprotective and regenerative effects a high PA content would be a disadvantage. The present article aims to discuss the problems associated with demanding a PA-free nutraceutical and elucidates adapting the HACCP concept with regards to the European Medical Association’s recommendations with the aim of an “as low as reasonably achievable” PA contamination (ALARA concept). In conclusion, the knowledge about the risk of PA contamination should prompt suppliers of herbs as well as manufacturers of herb-based products to voluntarily implement regular quality control measures within their Code of Practice and HACCP concept to minimize PA contamination. [ABSTRACT FROM AUTHOR]

A qualitative and quantitative method based on ultra-performance liquid chromatography (UPLC) and photodiode array (PDA) and electrospray ionization–quadrupole time-of-flight mass spectrometry (ESI-Q-TOF/MS) was developed, verified, and used to determine the quinoline alkaloids in Dictamnus dasycarpus and Zanthoxylum schinifolium, belonging to the Rutaceae family. Excellent analyte peak resolution was achieved on both quaternary and binary pumps by using acetonitrile and water containing 0.1% formic acid as the mobile phase using a C18 column. All alkaloids exhibited maximum absorption wavelength from 239 to 244 nm. The analytes were ionized as quasi-molecular ions [M + H]+ in MS and were characterized by using fragmentation ions formed by collision-induced dissociation (CID). This information was included in a library that was used to qualitatively identify alkaloids. The proposed method showed excellent linearity (r2 > 0.9988), limits of detection (PDA ≤ 25 ng/mL, MS ≤ 1.2 ng/mL), limits of quantification (PDA ≤ 75 ng/mL, MS ≤ 3.6 ng/mL), precision (in terms of relative standard deviation) of PDA ≤ 1.81% and MS 5.7%,. Liquid–liquid extraction (LLE) and solid-phase extraction (SPE) were conducted to separate and purify the alkaloids from the extracts. The analyte recoveries were determined to be PDA ≤ 103.11% and MS ≤ 104.45%. The method proceeded to deliver the comparable results for the determination of alkaloid components in samples. The developed UPLC-PDA and UPLC-ESI-Q-TOF/MS protocol facilitated the rapid, qualitative and quantitative identification of alkaloids in plants. [ABSTRACT FROM AUTHOR]

• Novel macrocyclic alkaloid isolated from crotalaria paulina. • Mass determination by HR mass spectrometry. • Structure determination by high field NMR spectroscopy. • DFT calculations to assist in the structure identification. Studies involving the structural elucidation of organic compounds isolated from natural products, along with theoretical calculations based on density functional theory (DFT), have confirmed the structures of many complex molecules. This work demonstrates the use of Nuclear Magnetic Resonance (NMR) spectroscopy and theoretical calculations in the structural identification of a pyrrolizidine alkaloid (PA), a secondary metabolite isolated from the plant Crotalaria paulina. Secondary metabolites are found in a wide variety of plant species and have diverse biological applications. In this study, the structural elucidation of the alkaloid was performed using high resolution mass spectrometry and nuclear magnetic resonance spectroscopy. Eight candidate structures were subjected to theoretical calculations at DFT level of theory. The experimental and calculated results were compared using the probability distribution DP4+ and corrected mean absolute error (CMAE) methods. The DP4+ result was 99.9%, and the CMAE for 13C NMR chemical shifts was 2.1 ppm, indicating a strong agreement between the experimental and theoretical chemical shifts for the stereochemistry represented by structure CS3 ((3 S ,4 R ,5 S ,8a R ,13a R)-3-ethyl-5‑hydroxy-3,4,5-trimethyl-4,5,8,8a,10,12,13,13a-octahydro-2 H [1,6]dioxacycloundecino[2,3,4- gh ]pyrrolizine-2,6(3H)‑dione). Ethylmethylcrotaline was coined as a nonsystematic nomenclature for structure CS3. [Display omitted] [ABSTRACT FROM AUTHOR]

The purpose of this review is to explore the medicinal, toxicological and chemophenetic importance of alkaloid-bearing African plant species. More than 20 000 alkaloids have been described in plants, and many of them contribute to the biological and therapeutic activity of important African traditional medicines and stimulants, such as Catha edulis, Catharanthus roseus, Coffea arabica, Mesembryanthum tortuosum, Pausinystalia johimbe, Physostigma venenosum and Voacanga africana. From a global selection of 817 of the most relevant medicinal plant species, 174 (21%) accumulate alkaloids and 33 (4%) of them are of African origin. The top five families amongst medicinal plants globally are the Fabaceae (15 spp.), Solanaceae (13), Apocynaceae (10), Rutaceae (9) and Papaveraceae (8). In Africa, the largest numbers of species are from the Fabaceae (5), Apocynaceae (4), Amaryllidaceae (3), Asteraceae (2), Rubiaceae (2) and Solanaceae (2). The alkaloid classes with the highest frequency among medicinal species globally are indole (27), isoquinoline (27) amine (13) and pyrrolizidine (11) derivatives, while in Africa indole (7), isoquinoline (5), amine (2) and purine (2) derivates are the most common. Macrocyclic pyrrolizidine alkaloids of the genus Senecio are of toxicological importance due to fatal liver poisoning in humans and animals, as well as contamination of commercial herbal products. Although unrelated plant species often produce the same compounds, alkaloids have been useful as chemophenetic and chemosystematic markers. Quinolizidine alkaloids have been particularly helpful in unravelling generic delimitations in Cape genistoid legumes, with unusual esters and both qualitative and quantitative discontinuities between genera and species. [ABSTRACT FROM AUTHOR]

With 1462 recognized species of Senecio (Asteraceae), the chemical diversity of the genus is exhaustive, yet largely unstudied. The dominant chemical families are cacalols (sesquiterpene lactones), flavonoids (flavans, flavones, isoflavones & flavanones), and macrocyclic pyrrolizidine alkaloids. These latter alkaloids are the cause of natural product toxification, either through adulteration or contamination inmultiple settings, ranging from honey to medicines and tea plantations. Most countries of the world include species of Senecio in their native flora, but issues of product toxification are commonly caused by invasive species from Africa. About a third of all Senecio are from Africa, most of which are among the southern African flora. As part of an ongoing investigation into the toxicity of southern African Senecio, our group has sampled over a hundred specimens from the wild and screened for toxic alkaloids. Our findings are that 5 - 10% of species sampled contain lethal quantities of retrorsine N-oxide, some exceeding 2% (g.g-1 dry weight). Unfortunately, some of these species have a similar appearance to those used in traditional medicine, which constitutes a risk to human health. Furthermore, where accidental cases of poisoning have occurred, it is possible that the toxic species we have identified were involved. With 1462 recognized species of Senecio (Asteraceae), the chemical diversity of the genus is exhaustive, yet largely unstudied. The dominant chemical families are cacalols (sesquiterpene lactones), flavonoids (flavans, flavones, isoflavones & flavanones), and macrocyclic pyrrolizidine alkaloids. These latter alkaloids are the cause of natural product toxification, either through adulteration or contamination in multiple settings, ranging from honey, to medicinesand tea plantations. Most countries of the world include species of Senecio in their native flora, but issues of product toxification are commonly caused by invasive species from Africa. About a third of all Senecio are from Africa, most of which are among the southern African flora. As part of an ongoing investigation into the toxicity of southern African Senecio, our group has sampled over a hundred specimens from the wild and screened for toxic alkaloids. Our findings are that 5 - 10% of species sampled contain lethal quantities of retrorsine N-oxide, some exceeding 2% (g.g-1 dry weight). Unfortunately, some of these species have a similarappearance to those used in traditional medicine, which constitutes a risk to human health. Furthermore, where accidental cases of poisoning have occurred, it is possible that the toxic species we have identified were involved. [ABSTRACT FROM AUTHOR]

Pyrrolizidine alkaloids (PAs) are natural toxins found in about 3%–5% of flowering plants. Dehydropyrrolizidine alkaloids contain a double bond in 1, 2-position of the necine bases, including retronecine type PAs (RET-PAs) and their N -oxides (RET N -oxide-PAs), and otonecine type PAs (OTO-PAs), and are known for their significant hepatotoxicity. Most dehydropyrrolizidine alkaloids are metabolically activated by cytochrome P450 (CYP450) enzymes to generate active pyrroles, which further bind to proteins to form pyrrole–protein adducts (PPAs). Methods for predicting PA-induced liver injury are generally performed on in vitro models with extremely low activities of CYP450 enzymes, which is different from the situation in vivo. In this regard, primary cultured mouse hepatocytes, which showed comparable CYP450 activity with the in vivo models, were applied to illustrate the structure–toxicity relationship of 13 dehydropyrrolizidine alkaloids, namely, eight RET-PAs, three RET N -oxide-PAs, and two OTO-PAs. PA-induced cytotoxicity and PA-generated PPAs were analyzed in primary mouse hepatocytes treated with different PAs. Results showed that PA-induced toxicity was correlated with the amount of PA-generated PPAs. RET-PAs and OTO-PAs were generally more toxic than RET N -oxide-PAs and generated higher amount of PPAs. PPAs were utilized to evaluate the efficiency of metabolic activation and predict the toxic potencies of dehydropyrrolizidine alkaloids. The proposed model could be a new approach for toxicity evaluation and risk control of exposure to PAs. Image 1 • Structure-toxicity relationship of 13 pyrrolizidine alkaloids is investigated. • Pyrrole-protein adducts are generated structure- and dose-dependently. • A new approach for risk control of exposure to pyrrolizidine alkaloids is proposed. [ABSTRACT FROM AUTHOR]

A novel steroid - pyrrolidinoisoquinoline alkaloid hybrid has been successfully synthesized by Diels-Alder reaction N-acyliminium ion cyclization sequence. [ABSTRACT FROM AUTHOR]

Beta-carboline alkaloids show a wide range of psychopharmacological effects (for example, some betacarboline alkaloids facilitate dopaminergic transmission and interact with dopaminergic receptors D1 and D2 in the striatum). This article presents data on neuroprotective effects of alkaloid compounds using computer simulation methods, docking-based virtual screening, and experimental pharmacology. The purpose of the study was to investigate the neuroprotective/stress-protective action of new derivatives of alkaloid compounds using the methods of computer simulation, docking-based virtual screening, and experimental pharmacology. Through ChemDraw, MGLTools programs, they have used computer modeling of the molecules of alkaloid derivatives, docking-based virtual screening, DRD2 receptor, and three-dimensional models of the ligand molecules. The binding energy of an individual conformation was used as a final result, which shows the strength of the interaction between the ligand and the target molecule. 22 compounds of alkaloids and their derivatives were studied. Virtual molecule modeling was performed for compounds and receptors, "ligand-target" molecule docking was carried out, and candidate compounds were selected. In vivo experimental studies of the neuroprotective effects of these compounds were conducted in the emotional stress model. The effects of harmine, norharmane, and guanine alkaloids on immobility time in the forced swimming test in mice, a model of depression in animals, were studied. A forced swimming test and an elevated plus-maze were used to determine the antidepressant and anxiolytic effects of harmine in rats. According to the docking results, the presented molecules of alkaloid compounds showed interactions with dopamine receptorD2. The results obtained in the "Elevated Plus Maze" test showed that the animals treated with 9-methoxy-2-phenyl-11H-indolisino[8,7-β]indole, lappaconitine and cytisine at a dose of 5 mg/kg, compared to rats in the control group, experienced an anxiolytic (anti-anxiety) actionin the experimental emotional stress. [ABSTRACT FROM AUTHOR]

A general strategy for the facile construction of both the ABDE and ABCD cores of tronocarpine, chippiine and dippinine alkaloids through the retrosynthetic disconnection of the polycyclic motifs into an indole or tryptamine fragment and a suitably functionalized alkyl chain is presented. The approach is enabled by an efficient Ir(III)-catalyzed, photoredox-mediated radical addition of tetramethyl 1-bromopentane-1,1,3,5-tetracarboxylate and dimethyl 2-bromopentanedioate selectively at C-2 of the indole. Subsequent intramolecular cyclization events furnish the desired ABDE and ABCD polycyclic cores in good preparative yields. [ABSTRACT FROM AUTHOR]

During the induction process of an in vitro callus culture of Argemone mexicana L. (Papaveraceae), the levels of two benzylisoquinoline alkaloids known as berberine and sanguinarine displayed opposing trends. While the berberine levels steadily decreased from the initial explant stage up to the early proliferation of unorganized parenchymatous cell masses, the sanguinarine content increased. Once the callus culture was established, sanguinarine was the primary alkaloid present and berberine could no longer be detected. However, upon shoot regeneration, the berberine accumulation recovered, but sanguinarine was found in the newly formed leafy tissue. After root formation, sanguinarine was relocated to this organ, whereas berberine was evenly distributed between both tissues. Explants from stem internodes did not form callus, and berberine—plus sanguinarine—containing axillary shoots emerged from lateral buds in the induction medium. In contrast to callus-derived shoots, no root formation was observed. Therefore, alkaloid synthesis in A. mexicana in vitro cultures is related to the level of tissue organization in different ways, and while berberine accumulation seems to require the presence of differentiated organs, this is not the case for sanguinarine. Moreover, leafy parts of rootless shoots acquired the capacity to accumulate sanguinarine, which is usually absent in aerial tissues of mature plants. However, when these shoots were rooted, sanguinarine was mainly located in the newly formed roots, while berberine was detected in the shoots at similar levels found in the roots. [ABSTRACT FROM AUTHOR]

The present study included the isolation of alkaloids from the nutmeg fruit (Myristica fragrans) where one of the alkaloid compounds in the nutmeg fruit was found, which is the existence of the aromatic and has carbonyl and phenol groups in addition to nitrogen. The isolated alkaloid showed antibacterial activity against Gram-positive bacteria (Staphylococcus aureus) and Gram-negative bacteria (Escherichia coli), while the alkaloid compound showed an antifungal effect against Candida albicans and Cryptococcous neoformans. No cytotoxicity of human blood solution in concentration (10-200 ppm) was shown in the isolated alkaloid compound. From this result, it was concluded that the alkaloid isolated from Myristica fragrans can be used in treatment of various disorders because of the effectiveness of the compound against bacteria and fungi. [ABSTRACT FROM AUTHOR]