Bioactive 12-oleanene triterpene and secotriterpene acids from Maytenus undata.

The aerial parts of Maytenus undata yielded four new 12-oleanene and 3,4-seco-12-oleanene triterpene acids, namely, 3-oxo-11α-methoxyolean-12-ene-30-oic acid (1), 3-oxo-11α-hydroxyolean-12-ene-30-oic acid (2), 3-oxo-olean-9(11),12-diene-30-oic acid (3), and 3,4-seco-olean-4(23),12-diene-3,29-dioic acid (20-epi-koetjapic acid) (5), together with the known 3,11-dioxoolean-12-ene-30-oic acid (3-oxo-18β-glycyrrhetinic acid) (4), koetjapic acid (6), and the 12-oleanene artifact 3-oxo-11α-ethoxyolean-12-ene-30-oic acid (7). Koetjapic acid (6) inhibited the growth of Staphylococcus aureus, methicillin-resistant S. aureus, and Pseudomonas aeruginosa, with an MIC range of 3.125−6.25 μg/mL. The new 3,4-secotriterpene acid 20-epi-koetjapic acid (5) potently inhibited rat neonatal brain microglia phorbol ester-stimulated thromboxane B2 (IC50 = 0.5 μM) and superoxide anion (IC50 = 1.9 μM) generation.