OLIGOCYCLIC AND MACROCYCLIC DITERPENES IN THYMELAEACEAE AND EUPHORBIACEAE OCCURRING AND UTILIZED IN YUNNAN (SOUTHWEST CHINA) .1. DAPHNANE TYPE DITERPENE ESTERS FROM DAPHNE-FEDDEI

From roots or the Chinese folk medical plant Daphne feddei Levl. three Daphne factors F1, F2 and F3 have been isolated. They proved identical with the known daphnane type 9,13,14-orthoesters huratoxin (F1), genkwadaphnin (F2) and with the known daphnane type 14-ester prohuratoxin (F3). From stem bark of the plant a new factor F, was obtained and identified as the 1,2-dihydro derivative of the known daphnane type 9,13,14-orthoester daphnetoxin. The factors F1-F4 exhibit moderate to strong irritant activity on the mouse ear. F4 assayed in the standard protocol 16 for tumor promoting activity on the back skin of mice was nearly inactive. Certain structure/activity relationships are pointed out along the conceptual idea to develop diterpene structures with diminished or abolished irritant and tumor promoting activities but retained immune stimulating, differentiating or otherwise antineoplastic activities.