Lignans from Virola sebifera Aubl., Virola sp., and Otoba parvifolia (
Mkfg.) A. Gentry (Myristicaceae) inhibited the in vitro growth of the
fungus cultivated by leaf-cutting ants of the species Atta sexdens rub
ropilosa Forel (Hymenoptera: Formicidae). A comparison of activity amo
ng the lignans was obtained.