Chemical study of the main ways of plant secundary metabolism: a bibliographic review

Abstract

The plant kingdom encompasses a vast availability and variety of plants used by man, since the beginning as forms of prevention and/or cure for both physical and psychological diseases. It is characteristic of living beings, the presence of metabolic activity, defining metabolism as: "set of chemical reactions that occur inside cells". In plant cells, it is divided between primary and secondary metabolism. While the primary is the set of processes that make an essential role in plants, such as photosynthesis; the secondary involves processes responsible for the relationships between the individual and the environment where they are, presenting an adaptive character, such as producing their own defenses. With this, from the survey and selection of materials published in scientific bases and books in the area, this bibliographic review aims to show the chemical importance of secondary metabolites in the plant's organism, and demonstrating the relevance the study of species diversity in the identification of active substances, components that have a therapeutic and/or toxic character. In addition to the knowledge about biosynthesis processes of the secondary metabolites: terpenes, phenolic compounds and alkaloids. As a result, it has that each plant species produces a set of chemical substances with a variety of functions, according to their development and defense needs. It was possible to observe that all secondary metabolites originate through glucose, in two main pathways: chiquimic acid and acetyl-CoA. The terpenes are biosynthesized from acetyl-CoA; the phenolic compounds by both routes; and the alkaloids from aromatic and aliphatic amino acids, which originate from chiquimic acid. It is concluded that it is important to study the functioning and the effective action of  secondary metabolites in the plants, to understand their defense mechanisms, and the possible execution of these applications in therapeutic techniques.