Toxic Compounds Produced by Plants

The compounds featured in Table 1.1 are considered briefly here. Pyrethrins are lipophilic esters that occur in Chrysanthemum spp. Extracts of flower heads of Chrysanthemum spp. contain six different pyrethrins and have been used for insect control (Chapter 12). Pyrethrins act upon sodium channels in a manner similar to p,p -DDT. The highly successful synthetic pyrethroid insecticides were modeled on natural pyrethrins. 

Veratridine is a complex lipophilic alkaloid that also binds to sodium channels, causing them to stay open and thereby disrupting the transmission of nerve action potential. It is found in the seeds of a member of the Liliaceae, Schoenocaulon 

Hypericin, from Hypericum perforatum (St. John s wort) 

Compounds Mode of Action against Same Target Comments 

Pyrethrins Upon Na+ channel of Pyrethroids Pyrethroids modeled on 

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These are just a few examples among many, and further examples are given in the references quoted at the end of this chapter. They are intended to illustrate the remarkable range of chemical structures among the toxic compounds produced by plants, which give evidence of the intensity of plant-animal warfare during the course of evolution. In some cases, they provide examples of how natural compounds have served—and continue to serve—as models for the development of new pesticides. 

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