Known triterpenes and their derivatives as scaffolds for the development of new therapeutic agents for cancer

Plants produce several bioactive secondary metabolites whose are used as therapeutic agents to treat various diseases, among them cancer. Triterpenes are a category of secondary metabolites that exert inhibitory activity against multiple intracellular and extracellular targets in euchariotic cells. These targets are proteins involved in apoptosis, cell development and differentiation, angiogenesis, metastasis and inflammatory processes. The inhibition of their functions leads to decreased cellular growth, differentiation and migration, resulting in antitumor activity, as shown by the numerous published experimental results. During recent years, synthetic triterpenoids derivatives have also been developed to implement potency and efficacy of starting compounds, allowing the obtainment of new compounds having promising anticancer activity. In this review we report the latest results regarding anticancer activity of some of the most studied triterpenes in the field, as well as of their semi-synthetic derivatives, with the aim to summarize the role of triterpenes as molecular leads for the development of new classes of antitumor agents.