Discovery of a New Triterpenoid and Chemical Profiling of Mudjala (Barringtonia acutangula), an Australian Indigenous Medicinal Plant

Mudjala bark, prepared from Barringtonia acutangula, is an Australian Aboriginal medicine traditionally used for pain relief, and previous studies have associated its activity with triterpenoid-rich fractions. However, the low-molecular-weight triterpenoids, which were major chromatographic constituents in these fractions, remained chemically unresolved. In this study, we define the aglycone-rich triterpenoid profile of Australian Mudjala bark and resolve its dominant inseparable aglycone mixture. The two major chromatographic isomeric acidic triterpenes could not be separated directly by reversed-phase HPLC, but isolation and hydrolysis of their corresponding C-28 glucosides enabled their assignment as bartogenic acid (1) and trachelosperogenin A (2). Overall, thirteen triterpenoids were assigned, including one new acylated barringtogenol C-type aglycone (5) and twelve known compounds (1–4, 6–13). The profile comprises three main chemical domains: 24,28-dioic acid aglycones and C-28 glucosides, acylated barringtogenol C-type oleananes, and common pentacyclic triterpene acids. These findings establish a compound-level chemical framework for the previously bioactive low-molecular-weight Mudjala fraction and support future quantitative and biological investigation.