Spasmolytic constituents from Eucalyptus camaldulensis var. obtusa leaves.

Phytochemical studies on the leaves of Eucalyptus camaldulensis var. obtusa have resulted in the isolation of a new triterpenoid camaldulin (3beta-formyloxyurs-11-en-28,13beta-olide) (1) along with ursolic acid lactone acetate (2), ursolic acid lactone (3), betulinic acid (4), and beta-sitosterol 3-O-beta-D-glucopyranoside (5). The structures were assigned on the basis of 1D and 2D NMR studies. Compounds 1-3 were tested for spasmolytic activity and were found to possess calcium antagonist activity.