Cycloartane and friedelane triterpenoids from the leaves of Caloncoba glauca and their evaluation for inhibition of 11β-hydroxysteroid dehydrogenases

Five new triterpenoids, caloncobic acids A and B (1 and 2), caloncobalactones A and B (3 and 4), and glaucalactone (5), along with the known compounds 3 beta,21 beta-dihydroxy-30-nor-(D:A)-friedo-olean-20(29)-en-27-oic acid (6) and acetyltrichadenic acid B (7), were isolated from the leaves of Caloncoba glauca. The structures of 1-5 were elucidated using spectroscopic methods. Compounds 1-7 were evaluated for their inhibitory activities against two isozymes of 11 beta-hydroxysteroid dehydrogenase (11 beta-HSD1 and 11 beta-HSD2). Compounds 1 and 2 exhibited strong inhibitory activities against mouse (EC50 132 and 13 nM) and human (EC50 105 and 72 nM) 11 beta-HSD1.