Abstract: The invention comprises a leucine aminopeptidase inhibitor (LAPI) having hemagglutination activity which is extracted from the seeds of Pentaclethra macroloba. The crude extract was found to comprise an active species having a molecular weight in the range 1.5-60 kilodaltons and further comprises an amino acid containing component, a fluorescent component and sugars. The basic unit of the active species contains approximately the following type and number of amino acid residues averaged over a plurality of separations and analyses: 3 aspartate, 3 threonine, 4.5 serine, 3.75 glutamic, 6.5 glycine, 3.5 alanine, 2.25 valine, 1.25 isoleucine, 2 leucine, 0.75 tyrosine, 1.25 phenylalanine, 5.25 lysine, 0.75 histidine, 2.25 arginine and 0.625 proline, and forms multimers, adduct, conjugate and similar species between by itself or with proteinaceous, fluorescent and sugar substance which may also be present. The active substance(s) act as an insecticide and have been found to increase insect mortality in bioassays.

Abstract: The invention comprises purified trypsin inhibitors extracted from the seeds of Pentaclethra macroloba. The crude extract was found to comprise two molecular weight ranges of 38-35 and 6-9 kDa which contain the active compounds. Within each molecular weight range, the trypsin inhibitors were found to exist in two isoforms. The lower molecular weight inhibitor exhibits surprising stability and activity after heating in aqueous solution at approximately 100.degree. C. for 30 minutes.