The Synthesis and Biosynthesis of Phytoalexins Produced by Cruciferous Plants

Phytoalexins are induced chemical defenses produced by plants in response to diverse forms of stress, including microbial attack. Although phytoalexins from over 30 different plant families have been isolated since Müller first proposed this term in 1940, crucifers were the first plants reported to produce phytoalexins containing sulfur and nitrogen. Most of the cruciferous phytoalexins are biogenetically derived from tryptophan but have rather different chemical structures as well as biological activities. The relatively large amounts of phytoalexins currently required for a diversity of chemical and biological studies are usually obtainable through synthesis, as isolation from plants is difficult and very time consuming. Herein we review work reporting the chemical structures, syntheses, and biosyntheses of cruciferous phytoalexins and present new perspectives on the potential applications of these compounds and analogs.