A hexacyclic ent-trachylobane diterpenoid possessing an oxetane ring from Mitrephora glabra
Li, C., Lee, D., Graf, T., Phifer, S., Nakanishi, Y., Burgess, J., Riswan, S., Setyowati, F. M., Saribi, A. M., Soejarto, D. D., Farnsworth, N. R., Falkinham, J. O., Kroll, D., Kinghorn, A. D., Wani, M., & Oberlies, N. (2005). A hexacyclic ent-trachylobane diterpenoid possessing an oxetane ring from Mitrephora glabra. Organic Letters, 7(25), 5709-5712.
[chemical reaction: see text]. Three new ent-trachylobane diterpenoids (1-3) were isolated and structures elucidated from Mitrephora glabra Scheff. (Annonaceae). Mitrephorone A (1) possesses a hexacyclic ring system with adjacent ketone moieties and an oxetane ring, both of which are unprecedented among trachylobanes. All compounds were evaluated for cytotoxicity against a panel of cancer cells, where 1 displayed the most potent and broadest activity, and against a battery of antimicrobial assays, where all compounds were approximately equipotent