[Frontiers in Bioscience 11, 2354-2370, September 1, 2006]

Metabolism and Ecology of Purine Alkaloids

Ana Luisa Anaya 1, Rocio Cruz-Ortega 1 and George R. Waller 2

1Departamento de Ecologia Funcional, Instituto de Ecologia, Universidad Nacional Autonoma de Mexico. Mexico DF 04510, 2Department of Biochemistry and Molecular Biology, Oklahoma State University. Stillwater, OK 74078, USA


1. Abstract
2. Introduction
3. Classification of alkaloids
4. The importance of purine in natural compounds
5. Purine alkaloids
5.1. Distribution of purine alkaloids in plants
5.2. Metabolism of purine alkaloids
6. Biosynthesis of caffeine
6.1. Purine ring methylation
6.2. Cultured cells
7. Catabolism of caffeine
8. Caffeine-free and low caffeine varieties of coffee
8.1. Patents
9. Ecological role of alkaloids
9.1. Herbivory
9.2. Allelopathy
9.2.1.Mechanism of action of caffeine and other purine alkaloids in plants
10. Perspective
11. Acknowledgements
12. References


In this review, the biosynthesis, catabolism, ecological significance, and modes of action of purine alkaloids particularly, caffeine, theobromine and theophylline in plants are discussed. In the biosynthesis of caffeine, progress has been made in enzymology, the amino acid sequence of the enzymes, and in the genes encoding N-methyltransferases. In addition, caffeine-deficient plants have been produced. The ecology of purine alkaloids has not proved to be particularly promising. However, advances have been made in insecticidal and allelopathic fields, and in the role of microorganisms play in the changes that these compounds undergo in the soil. Caffeine inhibits cell plate formation during telophase throughout the development of coffee plants and other species.