New sesquiterpenes and acetylenes from Athanasia and Pentzia species

Chemical investigation of several Athanasia and Pentzia species afforded in addition to known compounds a new furansesquiterpene, a new guaianolide related to matricarin, two biogenetically interesting acetylenic acids and an eremophilenic acid. The structures were elucidated by spectroscopic methods. The delimitation of the South African genera Athanasia, Pentzia and Matricaria is discussed. From the observed constituents it is suggested that some species should be transferred from Athanasia to Pentzia or vice versa and that the South African Matricaria species are possibly better placed in Pentzia.