Lupan-Skeleton Pentacyclic Triterpenes with Activity against Skin Cancer: Preclinical Trials Evolution

Abstract

Skin cancer is an increasingly frequent pathology, with a dangerous high percentage of malignant melanoma. The use of synthetic chemotherapy raises the problem of severe adverse effects and the development of resistance to treatment. Therefore, the use of natural therapies became the focus of numerous research groups due to their high efficacy and lower systemic adverse effects. Among natural products evaluated as therapeutical agents against skin cancer, betulinic acid was emphasized as a highly selective anti-melanoma agent and is currently undergoing phase II clinical trials as topical application. Several other pentacyclic triterpenes exhibit antiproliferative activities. This chapter aims to present the latest main discoveries in the class of pentacyclic triterenes with antitumor effect and the evolution of their preclinical trials. Furthermore, it includes reports on plant sources containing pentacyclic triterpenes, as well as the main possibilities of their water solubilization and cancer cell targeting. A review on recent data regarding mechanisms of action at cellular and molecular levels complements information on the outstanding medicinal potential of these compounds