Triterpene Derivatives as Inhibitors of Protein Involved in the Inflammatory Process: Molecules Interfering with Phospholipase A2, Cycloxygenase, and Lipoxygenase

Over the past years, there was an explosion in the knowledge of the protein target and molecular mechanism associated with various disease types and in the new research of drugs of natural origin. The key idea is to evaluate bioactive natural products interacting with protein domains of different genetic origin but structurally preserved to develop libraries of compounds biologically validated and selected from an evolutionistic point of view. Compared with synthetic compounds, natural products have a major number of unused scaffolds and are not comparable to the libraries of synthetic compounds, and could represent a promising starting point for the discovery of new bioactive compounds. Many natural products are reported to interact with proteins involved in serious diseases, such as inflammation and cancer. Recently various chemical classes of plant secondary metabolites have emerged as potential therapeutic compounds in several inflammatory diseases. Owing to the findings that triterpenoids, a common class of plant secondary metabolites, have anti-inflammatory and anti-cancer effects on humans, the interest in their potential application in human health and disease is increasing. The present review describes anti-inflammatory triterpenes derivatives from plant and fungi reported during the last two decades in order to provide an account of this field of investigation, sorting compounds according to their targets, phospholipase A2 (PLA2), cycloxygenase (COX), and lipoxygenase (LOX). The attempt is also being made to enumerate the possible leads for further synthetic and drug discovery program development.