Rearranged jatrophane-type diterpenes from Euphorbia species. Evaluation of their effects on the reversal of multidrug resistance

Abstract

The rearranged jatrophane-type diterpenes (1 - 3), isolated from the Me2CO extracts of Euphorbia portlandica and Euphorbia segetalis, were examined for their effects on multidrug resistance (MDR) in mouse lymphoma cells. Compounds 2 and 3 revealed to be active with the latter being more active than the positive control verapamil, a known resistance modifier. The new compound 1, named portlandicine, was isolated from Euphorbia portlandica and its structure characterised by high-field NMR spectroscopic methods including 2D NMR techniques: COSY, HMQC, HMBC and NOESY. The known diterpene 2, together with aleuritolic acid (4), oleanolic acid (5), and betulin diacetate (6), were also isolated from the same species.