A new family of tricyclic alkaloids from Myrmicaria ants

The poison gland secretion of the African ant, Myrmicaria opaciventris, contains three families of new alkaloids. These alkaloids are represented by a ''monomeric'' type with 15 carbon atoms in a row forming derivatives of indolizines, while the two other families are ''dimers'' and ''trimers'' with 30 and 45 carbon atoms, respectively. The major constituents of the low molecular weight alkaloids are identified to be pyrrolo[2,1,5-cd]indolizines, highly dominated by 1-ethyl-3,4,4a,5,6,7-hexahydro-2-((1Z)-1-propenyl)-pyrrolo[2,1,5-cd]indolizine, myrmicarin 215A. The higher molecular weight components show complex oligocyclic structures, which are closely related to the pyrroloindolizines. The alkaloid pattern shows a high degree of intraspecific variation. Copyright (C) 1996 Elsevier Science Ltd