Oleanane derivatives for pharmaceutical use: a patent review (2000-2016)

Introduction: Oleanolic acid has been considered a good start molecule for synthetic exploitation. Thus hundreds of oleanane triterpenoids have been synthesized and patented. Also many oleanane saponins have been patented for their biological activities and possible pharmaceutical use. Areas covered: Patents reporting the biological activities of oleanane derivatives and saponins with oleanane-type aglycones were examined. Among the synthesized oleanane derivatives, the most promising seem to be 2-cyano-3,12-dioxoolean-1,9(11)-dien-28-oic acid derivatives which interfere with many pathways involved in inflammation, oxidative stress and cell proliferation. Regarding oleanane-type saponins, several patents claiming their antiproliferative activity or their possible use as adjuvants in vaccines, were reported. Expert opinion: Despite the great number of synthesized oleanane triterpenoids, only CDDO-Me entered clinical development as a possible drug for the treatment of chronic kidney disease (CKD) but a phase 3 clinical trial was terminated due to heart-related adverse effects. Further phase 2 clinical trials of CDDO-Me are in progress for the treatment of CKD and PAH (pulmonary arterial hypertension) patients without heart-related risk factors. Additional investigations leading to compounds with an improved activity/toxicity profile along with well-designed preclinical and clinical trials are needed. Regarding oleanane-type saponins, the real perspective seems to be as adjuvants in vaccines.