Recent insights into the emerging role of triterpenoids in cancer therapy: part I

Natural products and/or their derivatives represent more than half of currently available drugs, and in the case of cancer this proportion surpasses 60%. Triterpenoids are a large group of natural compounds found in numerous living organisms, and particularly prevalent in plants, that have attracted great attention especially for their antineoplastic and anti-proliferative agents on various cancer cell lines for the development of novel pharmaceutical drugs. The recent developments on the antitumor properties of natural and synthetic triterpenes belonging to oleanane, dammarane, hopane, lanostane and ursane groups with a special focus on the structure-activity relationship are described.