ETHNOPHARMACOLOGICAL RELEVANCE : The leaves of Clausena anisata are used traditionally to expel maggots from wounds of animals in Zimbabwe. We have previously proved in the laboratory that the plant certainly affects the behaviour and growth of blowfly larvae. The objective of this study was to isolate and identify the active compounds responsible for this activity.MATERIALS AND METHODS : The acetone extract of C. anisata leaf powder was separated by
solvent-solvent partition into five fractions. The n-hexane fraction was the most active in the
larvicidal assay and therefore subjected to open column chromatography on silica gel. RESULTS : The isolated compound was identified by nuclear magnetic resonance (NMR) and
mass spectroscopy (MS) as the pyranocoumarin, seselin, chemically known as 2',2'-
dimethylpyranocoumarin . It inhibited feed intake in the first and second instars of blowflylarvae at the minimum concentration tested of 1 ppm resulting in significant lower mass pupae
(13.5 ± 0.5 mg and 22.4 ± 0.4 mg for the first and second instar larvae respectively)
compared to the solvent control group (26.19 ± 0.8 mg) (p < 0.05).
CONCLUSIONS : This is the first report of the isolation of seselin from the leaves of C. anisata
and the first report of the compound having an effect against blow fly larvae.