Pyrrolizidine Alkaloids in the Food Chain: Is Horizontal Transfer of Natural Products of Relevance?

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.

Assessment of Toxic Pyrrolizidine and Tropane Alkaloids in Herbal Teas and Culinary Herbs Using LC-Q-ToF/MS

Pyrrolizidine alkaloids are secondary metabolites produced by plants as a defense against insects. These can cause acute or chronic toxicity in humans. Therefore, avoiding potential poisoning from the consumption of tea and culinary plants contaminated with pyrrolizidine alkaloids (PAs), pyrrolizidine alkaloids N-oxides (PANOs), and tropane alkaloids (TAs) is important for human health and food safety. Therefore, it is important to determine the levels of these substances with reliable and highly accurate methods. In this study, the PAs, PANOs, and TAs in herbal teas and culinary herbs sold in Turkish markets were identified and their levels were determined. Thus, the general profiles of herbal teas and culinary herbs in Turkey were revealed, and the compliance of the total amounts of PA and TA with the regulations was examined. The identification and quantification of 25 PAs and N-oxides and 2 TAs (atropine and scopolamine) in the samples was performed with a liquid chromatography-quadrupole time-of-flight tandem mass spectrometer (LC-Q-ToF/MS). At least a few of these substances were detected in all of the tested herbal teas and culinary herbs. The total contents of the black tea, green tea, mixed tea, flavored tea, chamomile tea, sage tea, linden tea, fennel tea, rosehip tea, peppermint, and thyme samples ranged from 4.6 ng g-1 to 1054.5 ng g-1. The results obtained shed light on the importance of analyzing the total dehydro PA, PANO, and TA amounts in plant-based products consumed in diets with sensitive and accurate methods, and they highlight the necessity of performing these analyses routinely in terms of food safety.

Natural Compounds in Plant-Based Food

Plant-based foods include a wide range of products, such as fruits, vegetables, herbs and spices, as well as food products based on them, such as sauces, soups, or beverages [...].

Metabolic Toxification of 1,2-Unsaturated Pyrrolizidine Alkaloids Causes Human Hepatic Sinusoidal Obstruction Syndrome: The Update

Saturated and unsaturated pyrrolizidine alkaloids (PAs) are present in more than 6000 plant species growing in countries all over the world. They have a typical heterocyclic structure in common, but differ in their potential toxicity, depending on the presence or absence of a double bond between C1 and C2. Fortunately, most plants contain saturated PAs without this double bond and are therefore not toxic for consumption by humans or animals. In a minority of plants, however, PAs with this double bond between C1 and C2 exhibit strong hepatotoxic, genotoxic, cytotoxic, neurotoxic, and tumorigenic potentials. If consumed in error and in large emouns, plants with 1,2-unsaturated PAs induce metabolic breaking-off of the double bonds of the unsaturated PAs, generating PA radicals that may trigger severe liver injury through a process involving microsomal P450 (CYP), with preference of its isoforms CYP 2A6, CYP 3A4, and CYP 3A5. This toxifying CYP-dependent conversion occurs primarily in the endoplasmic reticulum of the hepatocytes equivalent to the microsomal fraction. Toxified PAs injure the protein membranes of hepatocytes, and after passing their plasma membranes, more so the liver sinusoidal endothelial cells (LSECs), leading to life-threatening hepatic sinusoidal obstruction syndrome (HSOS). This injury is easily diagnosed by blood pyrrolizidine protein adducts, which are perfect diagnostic biomarkers, supporting causality evaluation using the updated RUCAM (Roussel Uclaf Causality Assessment Method). HSOS is clinically characterized by weight gain due to fluid accumulation (ascites, pleural effusion, and edema), and may lead to acute liver failure, liver transplantation, or death. In conclusion, plant-derived PAs with a double bond between C1 and C2 are potentially hepatotoxic after metabolic removal of the double bond, and may cause PA-HSOS with a potential lethal outcome, even if PA consumption is stopped.