Issues of Safe Use of Plant-Based Food Supplements: A Review

Background: The widespread use of specialized food products, including plant-based dietary supplements, is determined by a rich variety of biologically active constituents. However, some plants containing such bioactive compounds as pulegone, menthofuran, estragole, methyleugenol, safrole, and thujone may cause adverse health effects. Objective: To review recent domestic and international scientific papers in order to substantiate the importance of regulating maximum permissible levels of monoterpene ketones (pulegone, menthofuran, and thujone) and alkenylbenzenes (estragole, methyleugenol, and safrole) in plant raw materials and plant-based nutritional supplements. Materials and methods: We used the keywords pulegone, menthofuran, methyleugenol, estragole, safrole, and thujone to search Scopus, Web of Science, PubMed, and RSCI abstract and citation databases and then applied information analysis and expert examination techniques to summarize research data published in Russian and English languages in 2001–2021. The initial sample consisted of 43 articles, of which 13 were excluded after initial screening. The selection criteria included availability of data on metabolism of the organic compounds in question, their levels in herbs and herbal teas, toxic effects on experimental animals, and potential adverse health effects in humans. We selected 30 full-text scientific publications and classified their data by the type of interventions. Results: The analysis of numerous studies of monoterpene ketones and alkenylbenzenes indicates a toxic effect of these groups of compounds on experimental animals. The International Agency for Research on Cancer (IARC) has classified pulegone, methyleugenol and safrole in Group 2B, which means that they are possibly carcinogenic to humans. Human health risks from plant-based alkenylbenzenes contained in dietary supplements are also demonstrated. Conclusion: Our findings prove the need to take appropriate risk management measures in order to limit the use of certain plant species containing high concentrations of biologically active substances posing threat to human health and to regulate their permissible levels in plant-based supplements.