Euphorbia species contain series of macrocyclic diterpenoids which present as mono, di and sometimes triesters and were reported to possess several and diverse biological activities. The aim herein was to use the positive ion mode ultraperformance electron spray ionization mass spectroscopy (UPLC-ESI-MS) as an analytical tool for rapid screening and tentative identification of diterpenoids in the methylene chloride fractions of Euphorbia paralias and Euphorbia geniculate. The identification of compounds was based on ESI-MS and ESI-MS/MS fragmentation pattern, in addition to comparison with reported literature. Five classes were determined including tigliane, ingenane, lathyrane, daphnane and jatrophane diterpenoids esters. Each class of the detected diterpenoids obtained its characteristic ESI-MS/MS fragmentation which facilitates its identification. As a result, a total of fifty two diterpenoids were identified and characterized in E. paralias and E. geniculate. All of these compounds are first report in the two plants by this method. The results demonstrated that the used method could be a rapid, effective analytical tool for screening and characterization of diterpenoids in the complex systems of plants extracts.
