The marigold plant produces the<unk>  alpha-terthienyl, which functions as a nematicide. When exposed to near ultraviolet light, such as in sunlight, alpha-terthienyl generates the toxic singlet oxygen. Alpha-terthienyl results in damage to the respiratory, digestive and nervous system of larvae, resulting in 100% death rates in concentrations of 33 ppb. This makes it an interesting natural insecticide. Rose bengal and other singlet oxygen generating<unk> s are also used in synthetic organic chemistry. They have also found use in photodynamic therapy, where the toxin is activated by intense light to destroy cancer cells.
Phototoxin
Cyanotoxin
Hemotoxin
Dinotoxin
Chlorotoxin
Neurotoxin
Birtoxin
Diamphotoxin