Metabolism of Fenhexamid, Metalaxyl-M, Tebuconazole, Flurtamone, and Spirodiclofen in Cannabis sativa L. (hemp) Plants

The consumption of and demand for Cannabis sativa L. ( C. sativa, hemp) have been increasing because of its legalization in several parts of the world. Pesticides could be applied to manage the fitness of C. sativa, but their application has not been studied in detail from a metabolic perspective. This study examined the metabolic degradation of five pesticides after hydroponic root uptake: fenhexamid, metalaxyl-M, tebuconazole, flurtamone, and spirodiclofen. Young plants were hydroponically exposed to 10 μM solutions of the selected pesticides for 14 days. Plant extracts were analyzed by a high-resolution mass spectrometer. Known mechanisms degraded the pesticides in C. sativa . For example, hydroxylation of all pesticides was followed by glycosylation and malonic acid conjugation. In addition, desaturation, demethylation, and non-enzymatic degradation were detected and are in good agreement with the known pathways in regulatory guideline data of the investigated pesticides in traditional crop plants such as, for example, Triticum aestivum L. (wheat), Vitis vinifera L. (wine), and Lactuca sativa L. (lettuce). Therefore, young plants make for a reliable and fast model system for elucidating the metabolism of pesticides in C. sativa .