Anti-cancer and Anti-angiogenic Properties of Various Natural Pentacyclic Tri-terpenoids and Some of their Chemical Derivatives

Pentacyclic triterpenes are natural substances, synthesized and present in variable amounts in a large number of terrestrial and aquatic plants, which act not only as antioxidants and antimicrobials but also as poisons, antibiotics, protease inhibitors, and so on. From the organic chemistry point of view, they are compounds derived from isoprene. These compounds consist of 30 carbons with different substituents, which facilitate their chemical identification and confer different physico-chemical and molecular properties. During the last ten years, most of them have been reported to have a variety of interesting and significant biological properties, such as analgesic, anti-allodynic, anti-diabetic, anti-oxidant, anti-parasitic, antimicrobial, anti-viral, anti-atherogenic, anti-inflammatory, anti-proliferative, anti-tumour, growth-stimulating activities as well as cardioand neuro-protective activity. However, special attention has been focused on the study of their anti-tumour capacity, fundamentally, on the various molecular mechanisms involved in the induction of programmed cell death and the inhibition of metastatic activity, in different types of cancers. Researchers have also focused on the role that different RNA molecules play in the anti-tumour activity of the major triterpenes studied. In this review, we look at the recent advances reported on the anti-tumorigenic roles of the main representatives of this group of compounds, such as betulinic (BA), ursolic (UA), oleanolic (OA) and maslinic (MA) acids and some of their derivatives, with a special emphasis on cell apoptosis and angiogenesis.