Chemotaxonomy: The Role of Phytochemicals in Chemotaxonomic Delineation of Taxa

Chemotaxonomy is concerned with the systematic study of phytochemical variation between plants. This variation has been essentially used for classification purposes ever since 'folk taxonomies', based on certain obvious plant characteristics which were instinctively employed by mankind centuries ago which included characters such as edibility, taste, colour, smell and medicinal value were founded subjectively on such chemical properties. The growth in the knowledge of the chemical complexity of plants became high from the desires of Europeans for exotic spices and condiments which provoked investigations into their medicinal properties. This Knowledge about the subject was summarised in herbals and concentrated on information about physiologically active secondary metabolite such as alkaloids and saponins. During the eighteenth and nineteenth centuries knowledge in the field increased and some taxonomists made use of several chemical characteristics in attempts to delineate plants taxa and to demonstrate their phylogeny. Chemotaxonomy has undoubtedly made a big contribution to taxonomic work in the past and will most certainly continue to do so in future. The valuable information it offers is best used in conjunction with other sources of taxonomic evidence and thus a multidisciplinary approach is required in order to establish a system of classification which reflects natural relationships as accurately as possible.