Acanthospermolides and other constituents from Blainvillea acmella

The aerial parts of Blainvillea acmella afforded, in addition to widespread triterpenes, desacetyl ovatifolin, desacyl grazielic acid tiglate, 8β-[2-methylbutyryloxy]-9β-hydroxy-14-oxo-acanthospermolide, four new germacranolides and seven acanthospermolides. The roots gave ovatifolin, two widespread thiophenacetylenes and two daucane derivatives. Comparison of the data with those of cyclochaenin required a revision of its structure. The structures were elucidated by high field ¹H NMR spectroscopy. Biogenetic relationships and taxonomic aspects are discussed briefly.