Alkaloids derived from tryptophan: A focus on ergot alkaloids

Abstract

Ergot alkaloids are secondary metabolites with significantly toxicological and pharmacological relevance and have been identified in different fungi of Ascomycota and several families of higher plants. Lysergic acid amides or peptides produced by the fungus Claviceps purpurea of the family Clavicipitaceae, e.g., ergometrine, ergotamine, or ergotoxine, and their semisynthetic derivatives are widely used in modern medicine for treatment of diverse diseases. Large-scale productions of ergot alkaloids for pharmaceutical applications have been achieved by biotechnological processes including field cultivation of Claviceps purpurea on rye or in submerged cultures. Some members of the fungal family of Trichocomaceae such as Aspergillus fumigatus and Penicillium commune produce clavine-type ergot alkaloids. These substances consist merely of the ergoline ring system as a common structure of most ergot alkaloids and lack an amide or peptidyl moiety in comparison to ergoamides or ergopeptines. Diverse analytical methods were developed for detection and determination of ergot alkaloids as mycotoxins in foods, cereals, and livestock feeds. Significant progress has also been achieved on the molecular biological and biochemical investigations of ergot alkaloid biosynthesis in the last years. The reaction steps from prenylation of tryptophan to formation of the ergoline ring system have been studied in detail.