Isolation, characterization, and biological activity of naphthoquinones from Calceolaria andina L.

Two compounds recognized as responsible for the insecticidal activity of ex tracts of Calceolaria andina L. (Scrophulariaceae) have been isolated and c haracterized as 2-(1,1-dimethylprop-2-enyl)3-hydroxy-1,4-naphthoquinone and the corresponding acetate, 2-acetoxy-3-(1,1-dimethylprop-2-enyl)-1,4-napht hoquinone. Their activities against 29 pest species and 9 beneficial specie s of arthropod from a total of 11 orders have been determined. Activities a gainst homopteran and acarine species are of the same order as those of est ablished pesticides, and, significantly, no cross-resistance is observed fo r strains resistant to established classes of insecticide. Mammalian toxici ties are low.