Insecticidal activity of daphnane diterpenes from Lasiosiphon kraussianus (Meisn) (Thymelaeaceae) roots

A methanol extract of roots of Lasiosiphon kraussianus (Meisn) (Thymelaeace ae) showed potent insecticidal activity against Aphis gossypii (Glov) and D rosophila melanogaster (Meig). Bioassay-driven fractionation of this extrac t led to the isolation and characterisation of two known daphnane diterpeno ids: Excoecaria toxin (1) and wikstrotoxin D (2). The two natural products were inferior to methomyl in activity against A gossypii and Myzus persicae (Sulz) in contact assays but were superior in ingestion assays against D m elanogaster. This is the first report on insecticidal activities of compoun ds 1 and 2. AChE was insensitive to the two natural products. (C) 1999 Soci ety of Chemical Industry.