Characterization of an insecticidal coumarin from Boenninghausenia albiflora.

The leaves of Boenninghausenia albiflora afforded an insecticidal coumarin which was identified as murraxocin (7-methoxy-8-[1'-ethoxy-2'-hydroxy-3'-methyl-but-3'enyl]-coumarin) (1), on the basis of extensive 1- and 2-dimensional NMR experiments. This compound has previously been isolated from Murraya exotica but this is the first report of the full (1)H and (13)C data for this compound. This natural product was evaluated against important forest insect pests and was active against Plecoptera reflexa, Clostera cupreata and Crypsiptya coclesalis at different concentrations varying from 1.0% to 5% w/v. In the crude extract 70% mortality was observed, and for compound 1 80% mortality was observed at a concentration of 1.0% w/v. The percentage of insect mortality increased in a dose-dependent manner. Coumarins are poorly studied insecticides and there is potential to exploit this chemically simple group of natural products.