Methyl 4-hydroxy-3-(3'-methyl-2'-butenyl)benzoate, major insecticidal principle from Piper guanacastensis

Abstract

The CHCl3-soluble extract of Piper guanacastensis (Piperaceae) was found to have noteworthy insecticidal activity to Aedes atropalpus mosquito larvae (LC(50) 80.5 mu g/mL). Bioassay-guided fractionation afforded methyl 4-hydroxy-3-(3'-methyl-2'-butenyl)benzoate (1) as the major bioactive constituent (LC(50) 20.5 mu g/mL). The separation of compound 1 from its transesterification artifact (2), ethyl 4-hydroxy-3-(3'-methyl-2'-butenyl)benzoate was achieved by recycling reversed-phase HPLC. The flavonoids acacetin, chrysin, and pinostrobin were also isolated from the active fraction but did not display insecticidal properties.