Abstract
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.
Acknowledgements
The authors thank Dr. A. Mudd, Mr. M. Hedges and Miss. J. Orgill for technical assistance, Dr. N.F. Janes for advice and JEOL (UK) Ltd for 2D NMR facilities. The authors are grateful to Prof. L.M.V. Tillekeratne of University of Colombo, Sri Lanka, for supplying plant material. The study received financial support from BTG International Limited. IACR-Rothamsted receives grant-aided support from the Biotechnology and Biological Sciences Research Council of the U.K.