Heliotropium species contain heliotrine, a pyrrolizidine alkaloid, which is both carcinogenic and genotoxic. In male rats, increase in pancreatic islet cell tumours, transitory cell papillomas of the urinary bladder, intestinal testicular tumours. DNA_adduct formation and chromosomal abberations in vivo and in vitro, indicating genotoxicity. Heliotropium species also contain lasiocarpine, a pyrrolizidine alkaloid, which is both carcinogenic and genotoxic. Angiosarcomas of the liver produced.

van den Berg, S.J.P.L., Restani, et al., P.. (2011). Levels of Genotoxic and Carcinogenic Compounds in Plant Food Supplements and Associated Risk Assessment. Food and Nutrition Science 2: 989-1010. Link