New tigliane and daphnane derivatives fromPimelea prostrata andPimelea simplex

Summary From the methanol extract ofPimelea prostrata, prostratin (I) and 2 autoxidation products have been isolated. They are tigliane derivatives and relatively nonirritant on the mouse ear. The irritant pimelea factor P₅ (IIa) also with a tigliane skeleton and related to mancinellin (IIb), as wellas the irritant diterpene ester pimelea factor P₁ (IIa, simplexin) with daphnane skeleton, were found to be present in bothP. prostrata andP. simplex. Further the irritant homologue of simplexin, pimela factorIIIb was detected inP. prostrata. Some biogenetic consequences of these findings are discussed.Acknowledgment: The authors are deeply indebted to Dr T. Cashmore (Palmerton North, New Zealand) and Dr H. B. Roberts (Sydney, Australia) for kindly supplying plant materials.