Chapter 2 Ergot Alkaloids – Biology and Molecular Biology

Abstract

Publisher Summary This chapter discusses the biology and molecular biology of ergot alkaloids (EA). The EA are among the most important natural pharmaceuticals and toxins in human history. The EA are characterized by the tetracyclic ergoline ring system or by related tricyclic alkaloids open between N(6) and C(7) (ergoline numbering). They are categorized as clavines, lysergic acid (1) and its simple amides, and ergopeptines. The distribution of organisms possessing EA appears disjointed, including two orders of fungi and three plant families. The EA-producing fungi are in the Eurotiales and Hypocreales, two distantly related orders within the phylum Ascomycota. The main ecological roles of EA in nature are probably to protect the fungi from consumption by vertebrate and invertebrate animals. The EA produced by plant-symbiotic fungi (such as epichloe¨ endophytes) may protect the fungus by protecting the health and productivity of the host, which may otherwise suffer excessive grazing by animals. The EA, at levels typical of plants bearing these symbionts, can negatively affect the health of large mammal's as well herbivorous insects. Some clavines have substantial anti-bacterial properties, which might protect the fungus and, in some cases, their host plants from infection.