A new insecticidal protolimonoid from Aegle marmelos

Bioassay-directed fractionation of the ethyl acetate extracts of the stem bark of Aegle marmelos Correa (Rutaceae) afforded a new compound, named skimmiarepin C, along with skimmiarepin A. The latter is a known compound but isolation from A. marmelos is new. The new compound is a senecioate ester analogue of the latter. Full identification of the new compound was achieved using spectroscopic methods on the separated mono-acetate derivatives. Skimmiarepins A and C exhibit moderate insecticidal activity against Phaedon cochleariae and Musca domestica in comparison with natural pyrethrum extract. The two epimeric acetates of skimmiarepin C are both less active.