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.

An investigation on the constituents of the fresh, uncrushed leaves of Eucalyptus camaldulensis var. obtusa has led to the isolation of three new and one known triterpenoids. The new products were characterized by chemical and spectroscopic studies as camaldulic acid (20β-acetoxy-3βhydroxyurs-12-en-28-oic acid) (1), camaldulensic acid (3β,30-dihydroxy-11R-methoxyurs-12en-28-oic acid) (2) and camaldulenic acid (2R,3β-dihydroxyolean-11,13(18)-dien-28-oic acid) (3), whereas the known compound was identified as ursolic acid lactone (3β-hydroxyurs-11-en-13β(28)-olide).