Isoquinoline Alkaloids and Chemotaxonomy

Abstract

The isoquinoline alkaloids are a class of secondary metabolites classified into different groups, being the aporphinoids the most representative class. They are considered the second-largest class of alkaloids in terms of structural diversity staying behind only of indole alkaloids. The aporphines could be found in the most diverse families of the plant kingdom. Isoquinolines alkaloids have aroused great interest in chemists and pharmacists due to its wide spectrum of biological activities: highlighting dopaminergic and serotonergic, vasodilator, antiplatelet agents, antimicrobial, antiviral, and cytotoxic. Different methods are applied to improve the comprehension about the metabolic pathways of isoquinoline alkaloids biosynthesis. Those approaches contribute to chemotaxonomy: one of the most useful plant classification systems that currently exist. This class of secondary metabolites has been widely reported as chemotaxonomic markers. These technological advances concerning new methodologies and tools are used nowadays to study these chemotaxonomic relationships: since screening the chemical composition of plants extracts through analytical techniques, to the analysis of chemodiversity and chemosystematics allied through reported data in literature. In this chapter, we present the main metabolic pathways involving biosynthesis of some groups of isoquinoline alkaloids, their occurrence in different vegetable families, and a few methods used in the studies of chemotaxonomic relations.