Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: August 21, 1997
Publication Date: N/A
Technical Abstract: Higher plants must protect themselves from invasion by microorganisms through physical barriers and the production of a wide range of secondary chemicals. Many of these compounds also confer selective advantages by inhibiting competing plants. Phenolics constitute the largest group of plant secondary compounds. Phenolic compounds are primarily synthesized via the shikimic acid pathway, and constitute an extremely diverse group, many of which have been shown to be antimicrobial and/or phytotoxic. Phenolic compounds can be assigned to several chemical groups, such as simple phenolics (e.g. cinnamic and ferulic acids), lignins, coumarins, quinones, and flavonoids. Flavonoids are a biologically important and chemically diverse group which can be further divided into subgroups including anthocyanidins, flavones, flavanones, flavonols, isoflavones and chromones. Flavonoids may be either constitutive or induced by stimuli such as wounding or pathogenic attack. In particular the isoflavone phytoalexins (compounds formed de novo after microbial invasion), produced by members of the Fabaceae, have been the subject of much recent research. This article will attempt to summarize the published literature regarding the antimicrobial and phytotoxic effects of plant flavonoids and discuss their potential exploitation.