Isolation and structure elucidation of cytotoxic polyacetylenes and polyenes from Echinacea pallida

Two new dicarbonylic acetylenes (3, 4) and three known acetylenes (1, 2, 5) were isolated and characterized from the n-hexane extracts of Echinacea pallida roots. Compounds 1 and 2 exhibited low cytotoxicity on MIA PaCa-2 human pancreatic adenocarcinoma cells, while compounds 3-5 displayed moderate activity.