Hepatic phytotoxins in herbal medicines: A review of Africa's pyrrolizidine alkaloid-containing plants, their traditional uses, contamination pathways and associated health risks

Incidences of human exposure to pyrrolizidine alkaloids (PAs) and their adverse effects have previously been reported in three African countries. In view of the increasing intake of herbal remedies over the years, we highlight Africa's tropical and subtropical PA-containing plants commonly used in herbal preparations, and summarize their ethnomedicinal uses, contamination pathways and potential health risks. PA-containing plants and their honey-derived products were ascertained through searching peer-reviewed electronic databases, PubMed, Google Scholar, Science Direct, Web of Science, and Scopus databases from 2001 to 2023. Overall, 37 PA-containing plants were found to be used in herbal medicinal preparations in Africa, of which 25 belong to Asteraceae, Fabaceae (10), and Boraginaceae (2) plant families. Furthermore, three major paths of PA-contamination of herbal medicines were identified while PAs from the genera Chromolaena, Ageratum, Eupatorium, Crotalaria, Eupatorium, Echium, and Senecio were frequently detected in honey used in herbal preparations. It was also revealed that the adoption of the guidelines for Good Agriculture and Collection Practice could significantly reduce the risk of exposure to PAs. This review will be useful in facilitating the identification of PA-containing plants in the field so that they are not used in herbal preparations, whereas there is a need to minimize their health risks by monitoring and setting acceptable limits for PAs in herbal and food products.& COPY; 2023 SAAB. Published by Elsevier B.V. All rights reserved.