Structure-activity relationships among maytansinoids in their effect on the European corn borer,Ostrinia nubilalis (Hübner).

Five maytansinoids fromMaytenus (Celastraceae) andPutterlickia (Rhamnaceae) species were tested for biological activity against the European corn borerOstrinia nubilalis. Maytanbutine, maytansine, and maytanvaline, all of which contain an amino acid residue at C-3, were active and comparable in their effect on larvae to trewiasine, a known active, amino acid-containing maytansinoid fromTrewia nudiflora. Maytanacine, which has an acetate group at C-3, was not as active as maytansine, maytanvaline, maytanbutine, or trewiasine, but significantly retarded the development of the larvae. Normaysine, which has no oxygen substituent at C-3, had no significant effect on mortality and only moderate effect on development of the larvae. The presence of the amino acid moiety at C-3 appears to be an important factor for the biological activity of maytansinoids.