Pyrrolizidine Alkaloids: Chemistry, Pharmacology, Toxicology and Food Safety

Safety evaluation of Plukenetia volubilis seeds: a metabolomic profiling and network toxicology approach

Sacha Inchi (Plukenetia volubilis) seeds and oil have been integrated into daily diets. However, scientific reports have raised concerns regarding potential health risks associated with saponins and alkaloids in this seeds. This study employed a combination analysis using proton-NMR, GC-MS, LC-QTOF, and GNPS molecular networking to evaluate the chemical composition of these seeds. In silico toxicology analysis and in vitro cytotoxicity assays were conducted to investigate the potential toxicity effects of Sacha Inchi seeds and their contained metabolites. The results revealed that major components of these seeds are oils (linoleic, linolenic, and oleic acids) and sugars, with minor amounts of phytosterols and trigonelline, a pyridine alkaloid. GNPS analysis suggested the absence of saponins, instead, it identified trigonelline and a few other nitrogen-containing metabolites (amino acids and oligopeptides). In silico toxicology analysis indicated that this sample did not exhibit toxicity. Furthermore, in vitro cytotoxicity screening demonstrated no cytotoxic effects against NIH-3T3 cells, even at 400 μg mL-1. In general, these findings collectively indicated the absence of saponins, the presence of phytosterols and trigonellin (a pyridine alkaloid), and a low safety risk related to saponin and alkaloid content in the Sacha Inchi seeds.

Hepatoprotective potential of coconut inflorescence sap against paracetamol induced toxicity in hep G2 cell lines

Coconut Inflorescence Sap (CIS) is the sweet, oyster-white colored, non-fermented juice obtained from the immature inflorescence of the Coconut tree. Acetaminophen (N-acetyl-p-aminophenol, or paracetamol) is one of the most frequently used drugs worldwide as an antipyretic or analgesic. HepG2 cell lines were used as an experimental model for studying in vitro hepatotoxicity induced by Paracetamol. The present study aims to identify biologically active compounds of CIS using LCMS analysis and to elucidate the ameliorative potential of CIS in alleviating paracetamol-induced hepatotoxicity. LC-MS analysis revealed the presence of 17 bioactive compounds. HepG2 cells were pretreated with Paracetamol (20 mM) for inducing toxicity, and Silymarin at a concentration of 50 μg/ml was used as a standard drug. The morphological analysis and MTT assay showed effective recovery from toxicity in cells treated with CIS in a dose-dependent manner. CIS at 25 μg/ml potentially showed the highest percentage of inhibitory activity against the toxicity induced by paracetamol. The treatment with paracetamol significantly increased the indicators of liver toxicity - LDH, SGOT, SGPT, and Glut.S Transferase in the media.CIS administration also increased the total protein levels, SOD, and Catalase activity. The morphological analysis, MTT assay, cytocompatibility studies, determination of enzymatic activities, etc., confirms the significant hepatoprotective efficacy of CIS.

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.

Mass spectrometric analysis strategies for pyrrolizidine alkaloids

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.

Pyrrolizidine alkaloids from Jacobaea vulgaris Gaertn and theoretical studies on intramolecular interactions

Two undescribed pyrrolizidine alkaloids, 13-dehydrosenkirkine (1) and chloromethylretrorsine (2), along with three known analogues, onetine (3), retrorsine (4), and usaramine N-oxide (5), were isolated from Jacobaea vulgaris Gaertn. The structures of the undescribed compounds were elucidated by extensive spectrometric and spectroscopic techniques, including HRESIMS, NMR, calculated 13C-NMR DP4+ analysis and comparison with experimental and calculated ECD spectra. The undescribed compounds were evaluated for their antitumour activity against HT29, HeLa, and HepG2 cells. In addition, the intramolecular interactions and quadrupolar couplings were revealed by investigating the geometrical and electronic properties of three typical otonecine-type PAs in DFT theory.

Recent advances and challenges in the analysis of natural toxins

Natural toxins (NTs) are poisonous secondary metabolites produced by living organisms developed to ward off predators. Especially low molecular weight NTs (MW<∼1 kDa), such as mycotoxins, phycotoxins, and plant toxins, are considered an important and growing food safety concern. Therefore, accurate risk assessment of food and feed for the presence of NTs is crucial. Currently, the analysis of NTs is predominantly performed with targeted high pressure liquid chromatography tandem mass spectrometry (HPLC-MS/MS) methods. Although these methods are highly sensitive and accurate, they are relatively expensive and time-consuming, while unknown or unexpected NTs will be missed. To overcome this, novel on-site screening methods and non-targeted HPLC high resolution mass spectrometry (HRMS) methods have been developed. On-site screening methods can give non-specialists the possibility for broad "scanning" of potential geographical regions of interest, while also providing sensitive and specific analysis at the point-of-need. Non-targeted chromatography-HRMS methods can detect unexpected as well as unknown NTs and their metabolites in a lab-based approach. The aim of this chapter is to provide an insight in the recent advances, challenges, and perspectives in the field of NTs analysis both from the on-site and the laboratory perspective.

Insight into pyrrolizidine alkaloids degradation and the chemical structures of their degradation products using ultra high performance liquid chromatography and Q-Exactive Orbitrap mass spectrometry

Pyrrolizidine alkaloids (PAs), released into the environment by donor plants, are absorbed by crops or transported by animals, posing a global food safety concern. Photolysis is an effective way to eliminate harmful substances in the environment or food. Photolysis happens as PAs move among plants, environment and crops. In this study, we first investigated the photolysis and hydrolysis of 15 PAs and identified their degradation products via ultra-high performance liquid chromatography and Q-Exactive Orbitrap mass spectrometry. PAs were degraded under UV radiation but minimally affected by visible light from a xenon lamp, and solvent pH had little impact on their photolysis. PAs were stable in neutral and acidic solutions but degraded by 50% within 24 h in alkaline conditions. The degradation products of PAs were mainly PAs/PANOs isomers and some minor byproducts. Cytotoxicity and computational analysis revealed isomers had similar toxicity, with minor products being less toxic. This study is a precursor for revealing the potential PAs degradation dynamics in the environment and food products, providing a reference for systematic evaluations of potential health and ecological risks of their degradation products.

The desert woodrat (Neotoma lepida) induces a diversity of biotransformation genes in response to creosote bush resin

Liver biotransformation enzymes have long been thought to enable animals to feed on diets rich in xenobiotic compounds. However, despite decades of pharmacological research in humans and rodents, little is known about hepatic gene expression in specialized mammalian herbivores feeding on toxic diets. Leveraging a recently identified population of the desert woodrat (Neotoma lepida) found to be highly tolerant to toxic creosote bush (Larrea tridentata), we explored the expression changes of suites of biotransformation genes in response to diets enriched with varying amounts of creosote resin. Analysis of hepatic RNA-seq data indicated a dose-dependent response to these compounds, including the upregulation of several genes encoding transcription factors and numerous phase I, II, and III biotransformation families. Notably, elevated expression of five biotransformation families - carboxylesterases, cytochromes P450, aldo-keto reductases, epoxide hydrolases, and UDP-glucuronosyltransferases - corresponded to species-specific duplication events in the genome, suggesting that these genes play a prominent role in N. lepida's adaptation to creosote bush. Building on pharmaceutical studies in model rodents, we propose a hypothesis for how the differentially expressed genes are involved in the biotransformation of creosote xenobiotics. Our results provide some of the first details about how these processes likely operate in the liver of a specialized mammalian herbivore.

Mycotoxins and pyrrolizidine alkaloids in herbal dietary supplements

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.

Pyrrolizidine alkaloids are synthesized and accumulated in flower of Myosotis scorpioides

Pyrrolizidine alkaloids (PAs) are specialized metabolites that are produced by various plant families that act as defense compounds against herbivores. On the other hand, certain lepidopteran insects uptake and utilize these PAs as defense compounds against their predators and as precursors of their sex pheromones. Adult males of Parantica sita, a danaine butterfly, convert PAs into their sex pheromones. In early summer, P. sita swarms over the flowers of Myosotis scorpioides, which belongs to the family Boraginaceae. M. scorpioides produces PAs, but the organs in which PAs are produced and whether P. sita utilizes PAs in M. scorpioides are largely unknown. In the present study, we clarified that M. scorpioides accumulates retronecine-core PAs in N-oxide form in all organs, including flowers. We also identified two M. scorpioides genes encoding homospermidine synthase (HSS), a key enzyme in the PA biosynthetic pathway, and clarified that these genes are expressed in all organs where PAs accumulate. Phylogenetic analysis suggested that these two HSS genes were originated from gene duplication of deoxyhypusine synthase gene like other HSS genes in PA-producing plants. These results suggest that PAs are synthesized and accumulated in the flower of M. scorpioides and provide a possibility for a PA-mediated interaction between P. sita and M. scorpioides.

Exploring the antioxidant potential of endophytic fungi: a review on methods for extraction and quantification of total antioxidant capacity (TAC)

Endophytic fungi have emerged as a significant source of natural products with remarkable bioactivities. Recent research has identified numerous antioxidant molecules among the secondary metabolites of endophytic fungi. These organisms, whether unicellular or micro-multicellular, offer the potential for genetic manipulation to enhance the production of these valuable antioxidant compounds, which hold promise for promoting health, vitality, and various biotechnological applications. In this study, we provide a critical review of methods for extracting, purifying, characterizing, and estimating the total antioxidant capacity (TAC) of endophytic fungi metabolites. While many endophytes produce metabolites similar to those found in plants with established symbiotic associations, we also highlight the existence of novel metabolites with potential scientific interest. Additionally, we discuss how advancements in nanotechnology have opened new avenues for exploring nanoformulations of endophytic metabolites in future studies, offering opportunities for diverse biological and industrial applications.

Utilization of a novel human hepatocyte-endothelial cell coculture model to determine differential toxicities of pyrrolizidine alkaloid food contaminants

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.

Chemical Profile and Biological Potential of Scaptotrigona Bee Products (Hymenoptera, Apidae, Meliponini): An Review

Stingless bees belong to the Meliponini tribe and are widely distributed in the tropics and subtropics, where they perform important ecological services. Among the best distributed groups of stingless bees is the genus Scaptotrigona, which includes 22 species distributed throughout the neotropical region, including the area from Mexico to Argentina. Bees of this genus are responsible for the production of products such as honey, propolis, geopropolis and fermented pollen ("saburá"). This review aimed to provide an overview of the chemical composition and biological activities associated with derived products from stingless bees of the genus Scaptotrigona. The bibliographic review was carried out through searches in the Scopus, Web of Science, ScienceDirect and PubMed databases, including publications from 2003 to January 2023. The study of the chemodiversity of products derived from Scaptotrigona demonstrated the mainly presence of flavonoids, phenolic acids, terpenoids and alkaloids. It was also demonstrated that products derived from bees of the genus Scaptotrigona exhibit a wide range of biological effects, such as antibacterial, antioxidant, anti-inflammatory and antifungal activities, among other bioactivities. This review provides an overview of phytochemical and pharmacological investigations of the genus Scaptotrigona. However, it is essential to clarify the toxicity and food safety of these products.

Exploring the Biological and Phytochemical Potential of Jordan's Flora: A Review and Update of Eight Selected Genera from Mediterranean Region

Jordan's flora is known for its rich diversity, with a grand sum of 2978 plant species that span 142 families and 868 genera across four different zones. Eight genera belonging to four different plant families have been recognized for their potential natural medicinal properties within the Mediterranean region. These genera include Chrysanthemum L., Onopordum Vaill. Ex. L., Phagnalon Cass., and Senecio L. from the Asteraceae family, in addition to Clematis L. and Ranunculus L. from the Ranunculaceae family, Anchusa L. from the Boraginaceae family, and Eryngium L. from the Apiaceae family. The selected genera show a wide variety of secondary metabolites with encouraging pharmacological characteristics including antioxidant, antibacterial, cytotoxic, anti-inflammatory, antidiabetic, anti-ulcer, and neuroprotective actions. Further research on these genera and their extracts will potentially result in the formulation of novel and potent natural pharmaceuticals. Overall, Jordan's rich flora provides a valuable resource for exploring and discovering new plant-based medicines.

Multifaceted Anticancer Potential of Gnidia glauca (Fresen.) Gilg Leaf Alkaloids: Impact on Multiple Cellular Targets

Gnidia glauca (Fresen.) Gilg has demonstrated significant anticancer potential through multiple mechanisms, including apoptosis induction, as shown by the TUNEL assay against MCF-7 cells, modulation of tubulin polymerization, preservation of mitochondrial function indicated by the JC-1 assay, and inhibition of DNA polymerase α and β activities. Rationale for the present study is to investigate the potential anticancer properties of G. glauca leaf alkaloid extract. Fresh and healthy G. glauca leaves were cleaned, shade-dried, and the powder was defatted, extracted with 10% acetic acid in ethanol, and subjected for alkaloid extraction. The partially purified G. glauca leaf alkaloid extract was evaluated for its effects on tubulin polymerization, DNA polymerase activity, mitochondrial membrane potential, and apoptosis studies using human breast cancer (MCF-7) cells by flow cytometry. The extract was found to affect microtubule assembly in a concentration-dependent manner (15.125-250 μg/mL), indicating presence of alkaloids that function as spindle poison agents. Leaf alkaloid extract of G. glauca was also found to affect the mitochondrial membrane potential with IC50 value 144.51 μg/mL, and inhibited DNA polymerase α and β activities dose dependently, thus potentially interfering with DNA replication and repair processes. Leaf alkaloid extract also showed the potential to induce DNA damage of 53.6%, albeit somewhat less than the standard drug camptothecin (64.94%) as confirmed by the TUNEL assay. Additionally, the GgLAE (IC50 144.51 μg/mL) showed significant inhibition of MCF-7 cells proliferation after 24 h, revealing phase arrests in sub G0/G1, S, and G2/M. These findings suggest that G. glauca leaf alkaloid extract contains alkaloids that possess anticancer properties with multiple targets, making the plant a natural source for a promising phytochemical drug candidates for further evaluation in pre-clinical and clinical studies. Further investigations are warranted to determine the efficacy, safety, identification and characterization of the alkaloids, and evaluate and determine their potential applications in cancer therapy.

Pyrrolizidine Alkaloids in Foods, Herbal Drugs, and Food Supplements: Chemistry, Metabolism, Toxicological Significance, Analytical Methods, Occurrence, and Challenges for Future

Consumers are increasingly seeking natural alternatives to chemical compounds, including the use of dried aromatic plants as seasonings instead of salt. However, the presence of pyrrolizidine alkaloids (PAs) in food supplements and dried plants has become a concern because of their link to liver diseases and their classification as carcinogenic by the International Agency for Research on Cancer (IARC). Despite European Union (EU) Regulation (EU) 2023/915, non-compliance issues persist, as indicated by alerts on the Rapid Alert System for Food and Feed (RASFF) portal. Analyzing PAs poses a challenge because of their diverse chemical structures and low concentrations in these products, necessitating highly sensitive analytical methods. Despite these challenges, ongoing advancements in analytical techniques coupled with effective sampling and extraction strategies offer the potential to enhance safety measures. These developments aim to minimize consumer exposure to PAs and safeguard their health while addressing the growing demand for natural alternatives in the marketplace.

Pyrrolizidine alkaloid contamination of food in Africa: A review of current trends and implications

Pyrrolizidine alkaloids (PAs) contamination of foodstuffs has become a topical issue in recent years on account of its potential hepatotoxicity to consumers. This review therefore highlights human exposure to PAs across Africa, focusing on their occurrence, current trends of food contamination, and their associated health implications. A comprehensive search of peer-scientific literature and relevant databases, PubMed, Google Scholar, Science Direct, Web of Science and Scopus, was conducted from 2001 to 2023 focusing mainly on foodstuffs, including grains, herbs, teas, honey, and livestock products. The findings revealed that PA contamination is a prevalent issue in several African countries, with the primary sources of contamination attributed to the consumption of honey and the use of PA plants as herbs in food preparations. Additionally, poor farming practices have been found to influence the presence and levels of PAs in foodstuffs. To mitigate PA contamination in food and safeguarding public health across the continent, several strategies are proposed, including the implementation of stringent regulatory and quality control measures, adoption of Good Agricultural Practices, and public awareness campaigns to educate producers, consumers and beekeepers about the risks associated with PA-contaminated food products.

OCT1-dependent uptake of structurally diverse pyrrolizidine alkaloids in human liver cells is crucial for their genotoxic and cytotoxic effects

Pyrrolizidine alkaloids (PAs) are important plant hepatotoxins, which occur as contaminants in plant-based foods, feeds and phytomedicines. Numerous studies demonstrated that the genotoxicity and cytotoxicity of PAs depend on their chemical structure, allowing for potency ranking and grouping. Organic cation transporter-1 (OCT1) was previously shown to be involved in the cellular uptake of the cyclic PA diesters monocrotaline, retrorsine and senescionine. However, little is known about the structure-dependent transport of PAs. Therefore, we investigated the impact of OCT1 on the uptake and toxicity of three structurally diverse PAs (heliotrine, lasiocarpine and riddelliine) differing in their degree and type of esterification in metabolically competent human liver cell models and hamster fibroblasts. Human HepG2-CYP3A4 liver cells were exposed to the respective PA in the presence or absence of the OCT1-inhibitors D-THP and quinidine, revealing a strongly attenuated cytotoxicity upon OCT1 inhibition. The same experiments were repeated in V79-CYP3A4 hamster fibroblasts, confirming that OCT1 inhibition prevents the cytotoxic effects of all tested PAs. Interestingly, OCT1 protein levels were much lower in V79-CYP3A4 than in HepG2-CYP3A4 cells, which correlated with their lower susceptibility to PA-induced cytotoxicity. The cytoprotective effect of OCT1 inhibiton was also demonstrated in primary human hepatocytes following PA exposure. Our experiments further showed that the genotoxic effects triggered by the three PAs are blocked by OCT1 inhibition as evidenced by strongly reduced γH2AX and p53 levels. Consistently, inhibition of OCT1-mediated uptake suppressed the activation of the DNA damage response (DDR) as revealed by decreased phosphorylation of checkpoint kinases upon PA treatment. In conclusion, we demonstrated that PAs, independent of their degree of esterification, are substrates for OCT1-mediated uptake into human liver cells. We further provided evidence that OCT1 inhibition prevents PA-triggered genotoxicity, DDR activation and subsequent cytotoxicity. These findings highlight the crucial role of OCT1 together with CYP3A4-dependent metabolic activation for PA toxicity.

Pyrrolizidine Alkaloids-Pros and Cons for Pharmaceutical and Medical Applications

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.

Baiting Insects with Pyrrolizidine Alkaloids (PAs): A Fieldwork-Oriented Review and Guide to PA-Pharmacophagy

Since 1890, many observations of danaine butterflies visiting dry plants of several families in the Old and New World tropics have been published. For 50 years, it has been recognised that Danainae, along with various other insects, seek out 1,2-dehydropyrrolizidine ester alkaloids (PAs) independently of and in addition to their nutritive requirements and utilise them to increase their chances for survival and biological fitness. This represents an unusual type of insect-plant relationship ("PA-pharmacophagy"), with remarkable peculiarities but also with gaps in knowledge, many of which can be filled by employing PA-baiting. We review and analyse the history of records on the attraction of adult insects to PAs and unveil the complex background information on PA-chemistry, PA-producing plants ("PA-plants"), and PA-sequestering insects ("PA-insects") in order to come up with practical tips for successful baiting with PAs ("PA-baiting"). Studying PA-pharmacophagy integrates taxonomy, behaviour, and ecology with evolutionary biology, chemistry, and toxicology. With basic knowledge of PA-chemistry and bearing the general peculiarities of PA-plants and PA-insects in mind, PA-baiting can be conducted easily and successfully to address many questions on the multifaceted ecology of pyrrolizidine alkaloids. We aim to encourage field researchers in the tropics to employ PA-baiting as a valuable research method in this field of integrative biology.

Occurrence and associated health risks of pyrrolizidine alkaloids in supplements marketed in Ghana for improved sexual performance

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.

Pyrrolizidine Alkaloids in Food on the Italian Market

Pyrrolizidine alkaloids (PAs) are secondary metabolites produced by over 6000 plant species worldwide. PAs enter the food chain through accidental co-harvesting of PA-containing weeds and through soil transfer from the living plant to surrounding acceptor plants. In animal studies, 1,2-unsaturated PAs have proven to be genotoxic carcinogens. According to the scientific opinion expressed by the 2017 EFSA, the foods with the highest levels of PA contamination were honey, tea, herbal infusions, and food supplements. Following the EFSA's recommendations, data on the presence of PAs in relevant food were monitored and collected. On 1 July 2022, the Commission Regulation (EU) 2020/2040 came into force, repealed by Commission Regulation (EU) 2023/915, setting maximum levels for the sum of pyrrolizidine alkaloids in certain food. A total of 602 food samples were collected from the Italian market between 2019 and 2022 and were classified as honey, pollen, dried tea, dried herbal infusions, dried herbs, and fresh borage leaves. The food samples were analyzed for their PA content via an in-house LC-MS/MS method that can detect PAs according to Regulation 2023/915. Overall, 42% of the analyzed samples were PA-contaminated, 14% exceeded the EU limits, and the items most frequently contaminated included dried herbs and tea. In conclusion, the number of food items containing considerable amounts of PAs may cause concern because they may contribute to human exposure, especially considering vulnerable populations-most importantly, children and pregnant women.

Equine Crofton Weed (Ageratina spp.) Pneumotoxicity: What Do We Know and What Do We Need to Know?

Crofton weed (Ageratina adenophora) is a global and highly invasive weed, with ingestion causing severe respiratory disease in horses, leading to irreversible and untreatable pulmonary fibrosis and oedema. While reports of equine pneumotoxicity remain common in Australia and New Zealand, equine pneumotoxicity may be underdiagnosed in other countries where Crofton weed is endemic but poorly differentiated. The pathogenesis of Crofton weed toxicity following ingestion has been well described in a number of different animal models, including rodents, rabbits, and goats. However, induced toxicity is organ-selective across different animal species, and these vastly differ from the pathogenesis described in horses, both clinically and after experimental exposure. Sources of variation may include species-specific susceptibility to different toxins present in the plant, different mechanistic processes of toxicity, and species differences in toxin biotransformation and bioactivation across different organs. Considering disease severity and Crofton weed's invasiveness globally, assessing published toxicological and exposure data is necessary to advance research, identify specific toxins for horses, and possible prophylactic and therapeutic strategies. This review presents an overview of the available literature on equine toxicity, parallels between toxicity in horses and other animal species, and important aspects to be included in the future research agenda.

Chromatographic Methods for Detection and Quantification of Pyrrolizidine Alkaloids in Flora, Herbal Medicines, and Food: An Overview

Pyrrolizidine alkaloids (PAs) are natural toxins produced by some plants that gained special interest due to their potential hazardous effects in humans and animals. These substances have been found in wild flora, herbal medicines and food products raising health concerns. Recently, maximum concentration levels of PAs were established for some food products; however, maximum daily intake frequently surpasses the upper limit set by the competent authorities posing a health risk. Given the scarcity or absence of occurrence data on PAs in many products, there is an urgent need to measure their levels and establish safety intake levels. Analytical methods have been reported to detect and quantify PAs in different matrices. The commonly used chromatographic methodologies provides accurate and reliable results. Analytical methods include diverse steps as extraction and sample preparation procedures that are critical for sensitivity and selectivity of the analytical method. Great efforts have been directed toward optimization of extraction procedures, clean up and chromatographic conditions to improve recovery, reduce matrix effects, and achieve low limits of detection and quantification. Therefore, this paper aims to give a general overview about the occurrence of PAs in flora, herbal medicines, and foodstuff; and discuss the different chromatographic methodologies used for PAs analysis, namely extraction and sample preparation procedures and chromatographic conditions.

Toxicological effects of cyanobacterial metabolites on zebrafish larval development

Freshwater cyanobacteria are known worldwide for their potential to produce toxins. However, these organisms are also found in marine, terrestrial and extreme environments and produce unique compounds, other than toxins. Nevertheless, their effects on biological systems are still barely known. This work tested extracts of different cyanobacterial strains against zebrafish (Danio rerio) larvae and analyzed their metabolomic profiles using liquid chromatography combined with mass spectrometry. Strains Desertifilum tharense, Anagnostidinema amphibium, and Nostoc sp. promoted morphological abnormalities such as pericardial edema, edema in the digestive system region, curvature of the tail and spine in zebrafish larvae in vivo. In contrast, Microcystis aeruginosa and Chlorogloeopsis sp. did not promote such changes. Metabolomics revealed unique compounds belonging to the classes of terpenoids, peptides, and linear lipopeptides/microginins in the nontoxic strains. The toxic strains were shown to contain unique compounds belonging to the classes of cyclic peptides, amino acids and other peptides, anabaenopeptins, lipopeptides, terpenoids, and alkaloids and derivatives. Other unknown compounds were also detected, highlighting the rich structural diversity of secondary metabolites produced by cyanobacteria. The effects of cyanobacterial metabolites on living organisms, mainly those related to potential human and ecotoxicological risks, are still poorly known. This work highlights the diverse, complex, and unique metabolomic profiles of cyanobacteria and the biotechnological potential and associated risks of exposure to their metabolites.

Target screening method for the quantitative determination of 118 pyrrolizidine alkaloids in food supplements, herbal infusions, honey and teas by liquid chromatography coupled to quadrupole orbitrap mass spectrometry

An analytical procedure for the screening of 118 pyrrolizidine alkaloids (PAs) was successfully validated and applied to their quantitative determination in food supplements, herbal infusions, honey, and teas. It provides the reliable analyte identification by high-resolution tandem mass spectrometry (HRMS/MS), the accurate determination of 21 regulated PAs, and broad contamination profiles. 10% of 281 analyzed samples resulted contaminated at levels above the maximum levels (MLs) of European legislation. The contamination of herbal infusions of mixed plants can represent a possible health concern (23%; mean of PA sum above ML). A high number of PAs not included in the regulation was detected in honey and herbal food supplements, but their contribution was only relevant to the overall level in honey. The results indicate the need to continue collecting contamination data in food supplements and infusions of mixed herbs and to expand the PA-pool to be monitored in honey and related products.

An analytical platform for the screening and identification of pyrrolizidine alkaloids in food matrices with high risk of contamination

An analytical platform for the detection of pyrrolizidine alkaloids (PAs) in honey, pollen, teas, herbal infusions, and dietary supplements is proposed; it includes a wide-scope suspect screening method, based on a diagnostic product ion filtering strategy for the characterization of PAs, and a target screening and identification method for the high-throughput detection of 118 PAs of a high-resolution mass spectral library. Salting-out assisted liquid-liquid extraction of aqueous extracts combined to ultra-high performance liquid chromatography-high-resolution tandem mass spectrometry was employed. The limit of identification (0.6-30 µg kg^-1) of 28 standards were fit-for-purpose in PA-monitoring applications, with a false negative rate <1.3 % at 4 µg L^-1. The wide-scope suspect screening method allowed the tentative identification of 88 compounds. The screening of 282 commercial samples revealed a broad contamination of the studied matrices, demonstrating the effectiveness of the platform in detecting and identifying both target and untarget PAs.

Exploitation of In Vivo-Emulated In Vitro System in Advanced Food Science

Reasonable model construction contributes to the accuracy of experimental results. Multiple in vivo models offer reliable choices for effective evaluation, whereas their applications are hampered due to adverse features including high time-consumption, high cost and ethical contradictions. In vivo-emulated in vitro systems (IVE systems) have experienced rapid development and have been brought into food science for about two decades. IVE systems' flexibly gathers the strengths of in vitro and in vivo models into one, reflecting the results in an efficient, systematic and interacted manner. In this review, we comprehensively reviewed the current research progress of IVE systems based on the literature published in the recent two decades. By categorizing the IVE systems into 2D coculture models, spheroids and organoids, their applications were systematically summarized and typically exemplified. The pros and cons of IVE systems were also thoroughly discussed, drawing attention to present challenges and inspiring potential orientation and future perspectives. The wide applicability and multiple possibilities suggest IVE systems as an effective and persuasive platform in the future of advanced food science.

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.

UGT76F1 glycosylates an isomer of the C7-necic acid component of pyrrolizidine alkaloids in Arabidopsis thaliana

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.

Tobacco Alkaloid Assessment in a DSS-Induced Colitis Mouse Model with a Fully Humanized Immune System

Inflammatory bowel disease (IBD) refers to chronic intestinal immune-mediated diseases including two main disease manifestations: ulcerative colitis (UC) and Crohn’s disease (CD). Epidemiological, clinical, and preclinical evidence has highlighted the potential anti-inflammatory properties of naturally occurring alkaloids. In the present study, we investigated the potential anti-inflammatory activities of the tobacco alkaloids nicotine and anatabine in a dextran sulfate sodium (DSS)-induced UC mouse model with a fully humanized immune system. Our results show that nicotine significantly reduced all acute colitis symptoms and improved colitis-specific endpoints, including histopathologically assessed colon inflammation, tissue damage, and mononuclear cell infiltration. The tobacco alkaloid anatabine showed similar effectiveness trends, although they were generally weaker or not significant. Gene expression analysis in the context of biological network models of IBD further pinpointed a possible mechanism by which nicotine attenuated DSS-induced colitis in humanized mice. The current study enables further investigation of possible molecular mechanisms by which tobacco alkaloids attenuate UC symptoms.

Potency ranking of pyrrolizidine alkaloids in metabolically competent human liver cancer cells and primary human hepatocytes using a genotoxicity test battery

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.

Decoding Metabolic Reprogramming in Plants under Pathogen Attacks, a Comprehensive Review of Emerging Metabolomics Technologies to Maximize Their Applications

In their environment, plants interact with a multitude of living organisms and have to cope with a large variety of aggressions of biotic or abiotic origin. What has been known for several decades is that the extraordinary variety of chemical compounds the plants are capable of synthesizing may be estimated in the range of hundreds of thousands, but only a fraction has been fully characterized to be implicated in defense responses. Despite the vast importance of these metabolites for plants and also for human health, our knowledge about their biosynthetic pathways and functions is still fragmentary. Recent progress has been made particularly for the phenylpropanoids and oxylipids metabolism, which is more emphasized in this review. With an increasing interest in monitoring plant metabolic reprogramming, the development of advanced analysis methods should now follow. This review capitalizes on the advanced technologies used in metabolome mapping in planta, including different metabolomics approaches, imaging, flux analysis, and interpretation using bioinformatics tools. Advantages and limitations with regards to the application of each technique towards monitoring which metabolite class or type are highlighted, with special emphasis on the necessary future developments to better mirror such intricate metabolic interactions in planta.

Separation of pyrrolizidine alkaloids in different Senecio species using ultra-high performance supercritical fluid chromatography

Different Senecio species, especially S. inaequidens - a neophyte native to South Africa - have widely spread across Europe and now are found worldwide. The entire genus is known to contain toxic pyrrolizidine alkaloids (PAs), which renders them a possible health hazard to humans and livestock. As they can enter the food chain or occur as contaminants in herbal crops and phytopharmaceutical formulations (e.g. teas), efficient and straightforward assays for their qualitative and quantitative analysis are in high demand. Different techniques have been used for this purpose, most commonly HPLC or GC. As the analysis of PAs is a challenging task, alternative methodologies like ultra-high performance SFC (UHPSFC) may offer an additional benefit in terms of their separation efficiency and orthogonal selectivity. In this study an UHPSFC approach for the simultaneous determination of six PAs (free bases as well as N-oxides) is presented, which achieved the baseline separation of all standard compounds in seven min. Optimal separation was carried out in gradient mode on a Torus™ DEA column with 0.05% ammonia in methanol as modifier. The column temperature was 25 °C, ABPR 1900 psi and flow rate 1.1 mL/min, with a detection wavelength of 215 nm. The assay was validated and fulfilled all ICH criteria exhibiting good linearity (R² ≥ 0.9994), precision (inter-day variance ≤ 3.67%, intra-day variance ≤ 3.92%) and recovery rates (96.3-104.1%), with detection limits typical for SFC-PDA (≤ 4.24 µg/mL). Furthermore, it could conveniently be coupled to MS-detection, which increased the sensitivity significantly. To confirm practical suitability of the method, different Senecio samples were analyzed, indicating a high qualitative as well as quantitative difference in their PA profile (e.g. total amounts of PA between 0.09 and 4.63 mg/g).

Treatment Effects of Natural Products on Inflammatory Bowel Disease In Vivo and Their Mechanisms: Based on Animal Experiments

Inflammatory bowel disease (IBD) is a chronic, non-specific inflammatory disease of the intestine that can be classified as ulcerative colitis (UC) and Crohn's disease (CD). Currently, the incidence of IBD is still increasing in developing countries. However, current treatments for IBD have limitations and do not fully meet the needs of patients. There is a growing demand for new, safe, and highly effective alternative drugs for IBD patients. Natural products (NPs) are used in drug development and disease treatment because of their broad biological activity, low toxicity, and low side effects. Numerous studies have shown that some NPs have strong therapeutic effects on IBD. In this paper, we first reviewed the pathogenesis of IBD as well as current therapeutic approaches and drugs. Further, we summarized the therapeutic effects of 170 different sources of NPs on IBD and generalized their modes of action and therapeutic effects. Finally, we analyzed the potential mechanisms of NPs for the treatment of IBD. The aim of our review is to provide a systematic and credible summary, thus supporting the research on NPs for the treatment of IBD and providing a theoretical basis for the development and application of NPs in drugs and functional foods.

Risk assessment of short-term intake of pyrrolizidine alkaloids in food: derivation of an acute reference dose

Pyrrolizidine alkaloids (PA) are phytochemicals that are known to act as human hepatotoxins and are also considered to be genotoxic carcinogens. Several plant-derived foods are frequently contaminated with PA, like teas and herbal infusions, spices and herbs or certain food supplements. With respect to the chronic toxicity of PA, the carcinogenic potential of PA is generally regarded as the critical toxicological effect. The risk assessment of the short-term toxicity of PA, however, is internationally less consistent. The characteristic pathological syndrome of acute PA toxicity is hepatic veno-occlusive disease. High PA exposure levels may lead to liver failure and even death as documented by several case reports. In the present report, we suggest a risk assessment approach for the derivation of an acute reference dose (ARfD) for PA of 1 µg/kg body weight per day based on a sub-acute animal toxicity study in rats after oral PA administration. The derived ARfD value is further supported by several case reports describing acute human poisoning following accidental PA intake. The here derived ARfD value may be used for PA risk assessment in cases where the short-term toxicity of PA is of interest in addition to the assessment of the long-term risks.

Wild leafy vegetables: A potential source for a traditional Mediterranean food from Lebanon

Introduction

In Lebanon, wild leafy vegetables (WLVs) continue to be an essential component of people's diet. Nevertheless, little ethnobotanical research has addressed this important potential source for food and nutrition.

Methods

In this study, an ethnobotanical survey was carried out between 2018 and 2022 across 21 villages/towns involving 151 local informants by semi-structured interviews.

Results and discussion

A list of 158 plant species which was still gathered and consumed by traditional Lebanese communities was compiled. The species belonged to 21 families and the most diverse families were Asteraceae (77 species), Brassicaceae (22), and Apiaceae (11). Native species accounted for 147 of the cited species, five of which were endemics to Lebanon and Syria. According to the Relative Frequency of Citation (RFC) index, Anchusa azurea, Centaurea hyalolepis, Chondrilla juncea, Eruca vesicaria, Pseudopodospermum molle, Pseudopodospermum papposum, and Taraxacum sect. Taraxacum were reported for the first time among the top popular species. Basal rosettes were the main parts consumed both raw and/or cooked. Informants perceived a decline in availability primarily due to habitat loss and land degradation. According to the International Union for Conservation of Nature (IUCN), six of cited species were classified as globally threatened (EN or VU), five of which were narrow endemics. These species scored substantial RFC values. Findings indicate that WEVs of Lebanon offer a promising potential to support food diversity and dietary quality of traditional communities and that threatened endemic species present a high conservation priority. Future research on nutritional contents of these species and highly rated WLVs is recommended.

Alkaloids as Promising Agents for the Management of Insulin Resistance: A Review

BACKGROUND

Insulin resistance is one of the main factors that lead to the development of type 2 diabetes mellitus (T2DM). The effect of alkaloids on insulin resistance has been extensively examined according to multiple scientific researches.

OBJECTIVE

In this work, we aimed to summarize the interesting results from preclinical and clinical studies that assessed the effects of natural alkaloids (berberine, nigelladine A, piperine, trigonelline, capsaicin, nuciferine, evodiamine, mahanine, and magnoflorine) on impaired insulin sensitivity and worsened insulin resistance, which play a pivotal role in the pathogenesis of type 2 diabetes.

METHODS

In the current review, PubMed, ScienceDirect, Springer, and Google Scholar databases were used. The inclusion criteria were based on the following keywords and phrases: insulin sensitivity, insulin resistance, alkaloids and insulin resistance, alkaloids and type 2 diabetes, mechanisms of action, and alkaloids.

RESULTS

The outcomes reported in this review demonstrated that the selected alkaloids increased insulin sensitivity and reduced insulin resistance in vitro and in vivo evidence, as well as in clinical trials, through improving insulin-signaling transduction mainly in hepatocytes, myocytes, and adipocytes, both at cellular and molecular levels. Insulin signaling components (InsR, IRS-1, PI3K, Akt, etc.), protein kinases and phosphatases, receptors, ion channels, cytokines, adipokines, and microRNAs, are influenced by alkaloids at transcriptional and translational levels, also in terms of function (activity and/or phosphorylation). Multiple perturbations associated with insulin resistance, such as ectopic lipid accumulation, inflammation, ER stress, oxidative stress, mitochondrial dysfunction, gut microbiota dysbiosis, and β-cell failure, are reversed after treatment with alkaloids. Furthermore, various indices and tests are employed to assess insulin resistance, including the Matsuda index, insulin sensitivity index (ISI), oral glucose tolerance test (OGTT), and insulin tolerance test (ITT), which are all enhanced by alkaloids. These improvements extend to fasting blood glucose, fasting insulin, and HbA1c levels as well. Additionally, the Homeostasis Model Assessment of Insulin Resistance (HOMA-IR) and the Homeostasis Model Assessment of β-cell function (HOMA-β) are recognized as robust markers of insulin sensitivity and β-cell function, and it is noteworthy that alkaloids also lead to improvements in these two markers.

CONCLUSION

Based on the findings of the current review, alkaloids may serve as both preventive and curative agents for metabolic disorders, specifically type 2 diabetes. Nonetheless, there is an urgent need for additional clinical trials to explore the potential benefits of alkaloids in both healthy individuals and those with type 2 diabetes. Additionally, it is crucial to assess any possible side effects and interactions with antidiabetic drugs.

Detoxification of comfrey (Symphytum officinale L.) extract using natural deep eutectic solvent (NADES) and evaluation of its anti-inflammatory, antioxidant, and hepatoprotective properties

Comfrey (Symphytum officinale L.) contains rosmarinic acid which has different pharmacological activities, such as antioxidant and anti-inflammatory activities. However, the medicinal use of comfrey is limited by the hepatotoxic effect of lycopsamine in comfrey, which overshadows the health benefits of rosmarinic acid. Natural deep eutectic solvents (NADES) have a wide range of extraction properties, that provides a new approach to the detoxification of comfrey. In the present study, betaine-based and choline chloride-based NADES were screened for selective extraction of rosmarinic acid over lycopsamine. Ultrasonication was used in conjunction with NADES extraction. The chemical profile of the NADES extracts on antioxidant, anti-inflammatory and hepatotoxic activities were investigated using some chemical reagents. Betaine-urea (1:2 molar ratio, 50% water) obtained the highest content of rosmarinic acid and a low level of lycopsamine (1.934 and 0.018 mg/g, respectively). Betaine-urea was also shown to be more effective to extract rosmarinic acid compared to methanol-UAE under the same conditions, which gave lower rosmarinic acid and higher lycopsamine levels (0.007 and 0.031 mg/g, respectively). Betaine-urea extracts showed higher antioxidant and anti-inflammatory properties as compared with other NADES extracts, however, had lower hepatotoxic profile. This study recommends the use of betaine-urea to detroxify comfrey to open wider opportunities for the development of comfrey for medicinal use.

Naturally Occurring Plant Food Toxicants and the Role of Food Processing Methods in Their Detoxification

Some plant foods evolve defense mechanisms to protect themselves from predators by producing inherent chemicals as secondary metabolites such as cyanogenic glycosides, glycoalkaloids, glucosinolates, pyrrolizidine alkaloids, and lectins. These metabolites are beneficial for the plant itself but toxic to other organisms, including human beings. Some of these toxic chemicals are believed to have therapeutic benefits and are therefore used to protect against chronic health complications such as cancer. Inversely, short- and long-term exposure to significant amounts of these phytotoxins may end up with chronic irreversible negative health problems in important organ systems, and in severe cases, they can be carcinogenic and fatal. A systematic literature search of relevant published articles indexed in Google Scholar®, PubMed®, Scopus®, Springer Link®, Web of Science®, MDPI®, and ScienceDirect databases was used to obtain the necessary information. Various traditional and emerging food-processing techniques have been found to considerably reduce most of the toxicants in the food to their safest level. Despite their ability to preserve the nutritional value of processed foods, emerging food processing methods have limited application and accessibility in middle- and low-income countries. As a consequence, much more work is recommended on the implementation of emerging technologies, with additional scientific work on food processing methods that are effective against these naturally occurring plant food toxicants, particularly pyrrolizidine alkaloids.

Retrorsine Cooperates with Gut Microbiota to Promote Hepatic Sinusoidal Obstruction Syndrome by Disrupting the Gut Barrier

BACKGROUND AND AIMS

Hepatic sinusoidal obstruction syndrome (HSOS) is a life-threatening syndrome, and a cause is exposure to pyrrolizidine alkaloid (PA)-containing products. It is well-established that retrorsine (RTS), a representative Pas, insults hepatic sinusoidal endothelial cells and ensues congestion of hepatic sinusoids. However, little known about the impact of Pas on gut microbiota and intestinal barrier and inflammation in HSOS.

METHODS

Mice were gavaged with or without nonabsorbable antibiotics (ABX), followed by a single dose of RTS. The gut microbiota was examined by 16S rDNA sequencing.

RESULTS

ABX pretreatment significantly reversed RTS-induced liver damage. RTS altered gut microbiota composition, increasing Gram-negative bacteria and resulting in a sharp elevation of circulating lipopolysaccharides (LPS) in HSOS mice. Gut decontamination with ABX alleviated RTS-induced intestine inflammation, protected against disruption of the intestinal epithelial barrier and gut vascular barrier (GVB), and suppressed hepatic LPS-NF-κB pathway activation in RTS-induced HSOS. Importantly, the LPS level was positively correlated with MELD score in patients with HSOS. Elevated LPS in patients with HSOS confirmed that Gram-negative bacteria were involved in the pathogenesis of HSOS.

CONCLUSIONS

RTS, a PA, cooperated with gut dysbiosis to cause intestinal inflammation and gut barrier compromise that increased transport of gut-derived LPS into the liver through the portal vein, which contributed to the pathology of HSOS. Modulating the gut microbiota, protecting the intestinal barrier, and suppressing intestinal inflammation with prebiotics or antibiotics might be a useful pharmacologic intervention in HSOS.

Pyrrolizidine Alkaloid Extraction and Analysis: Recent Updates

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

Multi-Response Optimization of Pyrrolizidine Alkaloids Removal from Chrysanthemum morifolium by High-Pressure Extraction

As an ingredient in various foods, Chrysanthemum morifolium flower is popular due to its multiple health benefits. Pyrrolizidine alkaloids (PAs) are hepatotoxic secondary metabolites in Chrysanthemum family. Effects of high-pressure extraction (HPE) on PAs removal efficiency, as well as the retention efficiency of functional components, including chlorogenic acid, luteolin-7-β-D-glucopyranoside, 3,5-dicaffeyl quinic acid and total flavonoids, were investigated and optimized using response surface methodology (RSM). Pressure (0.1-200 MPa), numbers of cycles (1-5) and acetic acid concentration (0-10%) were chosen as the independent variables. The results indicated that the pressure was the most significant factors affecting all responses. The optimum HPE for removing Pas and retaining functional components were set at 124 MPa, with one cycle and with an acetic acid concentration of 10%. After comparing the experimental optimum values and predicted optimum values, the validity of RSM model was proved.

11H-Benzo[4,5]imidazo[1,2-a]indol-11-one as a New Precursor of Azomethine Ylides: 1,3-Dipolar Cycloaddition Reactions with Cyclopropenes and Maleimides

The possibility of generating azomethine ylides from 11H-benzo[4,5]imidazo[1,2-a]indol-11-one and amino acids is shown for the first time. Based on the cycloaddition reactions of these azomethine ylides with cyclopropenes and maleimides, cyclopropa[a]pyrrolizines, 3-azabicyclo[3.1.0]hexanes, and pyrrolo[3,4-a]pyrrolizines spiro-fused with a benzo[4,5]imidazo[1,2-a]indole fragment were synthesized. Spirocyclic compounds were obtained in moderate to good yields, albeit with poor diastereoselectivity. Density functional theory calculations were performed to obtain an insight into the mechanism of the 1,3-dipolar cycloaddition of 11H-benzo[4,5]imidazo[1,2-a]indol-11-one-derived azomethine ylides to cyclopropenes. The cytotoxic activity of some of the obtained cycloadducts against the human erythroleukemia (K562) cell line was evaluated in vitro by MTS-assay.

Natural Compounds and Products from an Anti-Aging Perspective

Aging is a very complex process that is accompanied by a degenerative impairment in many of the major functions of the human body over time. This inevitable process is influenced by hereditary factors, lifestyle, and environmental influences such as xenobiotic pollution, infectious agents, UV radiation, diet-borne toxins, and so on. Many external and internal signs and symptoms are related with the aging process and senescence, including skin dryness and wrinkles, atherosclerosis, diabetes, neurodegenerative disorders, cancer, etc. Oxidative stress, a consequence of the imbalance between pro- and antioxidants, is one of the main provoking factors causing aging-related damages and concerns, due to the generation of highly reactive byproducts such as reactive oxygen and nitrogen species during the metabolism, which result in cellular damage and apoptosis. Antioxidants can prevent these processes and extend healthy longevity due to the ability to inhibit the formation of free radicals or interrupt their propagation, thereby lowering the level of oxidative stress. This review focuses on supporting the antioxidant system of the organism by balancing the diet through the consumption of the necessary amount of natural ingredients, including vitamins, minerals, polyunsaturated fatty acids (PUFA), essential amino acids, probiotics, plants' fibers, nutritional supplements, polyphenols, some phytoextracts, and drinking water.

Plants in vitro propagation with its applications in food, pharmaceuticals and cosmetic industries; current scenario and future approaches

Plant tissue culture technique employed for the identification and isolation of bioactive phytocompounds has numerous industrial applications. It provides potential benefits for different industries which include food, pharmaceutical and cosmetics. Various agronomic crops i.e., cereals, fruits, vegetables, ornamental plants and forest trees are currently being used for in vitro propagation. Plant tissue culture coupled with biotechnological approaches leads towards sustainable agricultural development providing solutions to major food security issues. Plants are the rich source of phytochemicals with medicinal properties rendering them useful for the industrial production of pharmaceuticals and nutraceuticals. Furthermore, there are numerous plant compounds with application in the cosmetics industry. In addition to having moisturizing, anti-ageing, anti-wrinkle effects; plant-derived compounds also possess pharmacological properties such as antiviral, antimicrobial, antifungal, anticancer, antioxidant, anti-inflammatory, and anti-allergy characteristics. The in vitro propagation of industrially significant flora is gaining attention because of its several advantages over conventional plant propagation methods. One of the major advantages of this technique is the quick availability of food throughout the year, irrespective of the growing season, thus opening new opportunities to the producers and farmers. The sterile or endangered flora can also be conserved by plant micro propagation methods. Hence, plant tissue culture is an extremely efficient and cost-effective technique for biosynthetic studies and bio-production, biotransformation, or bioconversion of plant-derived compounds. However, there are certain limitations of in-vitro plant regeneration system including difficulties with continuous operation, product removal, and aseptic conditions. For sustainable industrial applications of in-vitro regenerated plants on a large scale, these constraints need to be addressed in future studies.

Seasonal Variability in Pyrrolizidine Alkaloids in Jacobaea alpina from the Trentino-Alto Adige Region (Northern Italy)

In recent years, increased attention has been given to plants containing toxic pyrrolizidine alkaloids (PAs). Jacobaea alpina (syn. Senecio cordatus) is a tall forb growing on mountain pastures and meadows containing such alkaloids and therefore, the plant is considered as a noxious weed in these environments. The repartition of toxic macrocyclic PAs in the plant and their evolution during the vegetation period has been studied in two populations. Eight PAs were found where senciphylline and senecionine accounted in most samples for more than 85 % of total alkaloids. Leaves in April and stems in May started with high PA concentrations (19-22 mg/g dry matter), then alkaloid levels declined. This decrease was more rapid in stems than in leaves. Depending on the population, fully developed inflorescences in June and July PA contents were higher or lower than in the respective leaves. Later, also in the inflorescences PA concentration decreased. Combined with growth data total alkaloid content in the whole plant as mg/plant was highest in midsummer and declined afterwards. Finally, new emerging leaves in September had high PA levels, which declined markedly towards the end of the season in November. In sum, over a large period PA concentration appeared to be high enough to present a health risk for grazing animals.