Euphosalicin, a new diterpene polyester with multidrug resistance reversing activity from Euphorbia salicifolia

A novel diterpene polyester, named euphosalicin (1), the first representati ve of a new class of bicyclic diterpenes, was isolated from the dichloromet hane extract of the whole plant of Euphorbia salicifolia, together with one known (2) and two new jatrophane diterpenes (3, 4). The new carbon skeleto n is formally derived from the jatrophane framework by incorporation of a g eminal methyl group in the ring system. Compound 1 was found to be more act ive than verapamil in reversing multidrug resistance in mouse lymphoma cell s. (C) 2000 Elsevier Science Ltd. All rights reserved.