Acetylated pseudoguaianolides from Parthenium hysterophorus and their cytotoxic activity.

Chemical examination of the flowers of Parthenium hysterophorus has resulted in the isolation of four acetylated pseudoguaianolides along with several known constituents. The structures of the compounds were derived from detailed studies of their spectral (1D and 2D NMR and FABMS) data and by comparison of the values with those of parthenin, a major known constituent of the plant. The cytotoxic activity of parthenin and the constituents was evaluated using Jurkat (human: T lymphocyte; acute T cell leukemia), HL-60 (human leukemia) and Hela (human cervical carcinoma) cells.