Decadal structural advances of oleanane-type pentacyclic triterpenoids and their pharmacological activities, a review (2015-2025).

The increasing global disease burden sustains interest in natural products as sources for therapeutic discovery. Among these, naturally occurring and semi-synthetic oleanane-type triterpenoids have attracted considerable attention because of their broad range of reported bioactivities and their wide distribution in nature. A literature search was conducted across PubMed, Web of Science Core Collection and Google Scholar using keywords "oleanane-type", "oleanolic acid-type" and "triterpenoids". Only studies reporting oleanane- or oleanolic acid-related triterpenoids with fully elucidated chemical structures were included, while articles focusing on other triterpenoid skeletons or lacking clear structural identification were excluded. Across 71 articles published over the past decade (2015-2025), 185 newly reported oleanane-type triterpenoids were summarized, highlighting the rapid expansion of structural diversity driven by advances in chromatographic separation and spectroscopic analysis.