An investigation of the seeds of Swietenia macrophylla and S. aubrevilleana
(Meliaceae) is reported. Three new compounds, augustineolide (1) and 3 bet
a,6-dihydroxydihydrocarapin (2) from S, macrophylla and 6-acetoxyhumilinoli
de C (3) from S. aubrevilleana were isolated and characterized along with f
ifteen known compounds. Four of the compounds were subjected to an antifeed
ant bioassay on the final instar larvae of Spodoptera frugiperda. The antif
eedant activity was comparable to that of bicyclononanolides previously tes
ted.(13).