Radioactive Tracer Feeding Experiments and Product Analysis to Determine the Biosynthetic Capability of Comfrey (Symphytum officinale) Leaves for Pyrrolizidine Alkaloids

This protocol delivers a method to determine the biosynthetic capability of comfrey leaves for pyrrolizidine alkaloids independently from other organs like roots or flowers. The protocol applies and combines radioactive tracer experiments with standard and modern techniques like thin layer chromatography (TLC), solid-phase extraction (SPE), high-performance liquid chromatography (HPLC) and gas chromatography-mass spectrometry (GC-MS).