Two new tirucallane-type triterpenes from the aerial parts of Euphorbia retusa

Abstract

Chemical characterization of the dichloromethane extract of Euphorbia retusa aerial parts by chromatographic methods afforded an inseparable mixture of two new tirucallane-type triterpenoids namely (3β, 24S)- and (3β, 24R)-tirucalla-7,25-diene-3,24-diol (1a and 1b) respectively, together with nine known compounds including six triterpenoids and three phenylpropanoids. Their structures were established on the basis of spectroscopic analyses, including 1D- and 2D- homo- and heteronuclear NMR experiments and mass spectrometry, as well as comparison with data from related compounds. The chemotaxonomic aspects were also discussed.