Chromatographic detection of sesquiterpene lactones in parthenium plants from northwest Argentina

Several chloroformic extracts containing some sesquiterpene lactones from autochtonous plants of Parthenium hysterophorus, collected in the province of Salta (Argentina), were separated and identified by high performance reversed-phase liquid chromatography with C 18 column and propanol-water mobile phases, using gradient elution and concentrations of propanol larger than 10% (v/v). Lactones previously purified and characterized by H 1 RMN, C 13 RMN, IR, and mass spectrometry, were used as standards. The objective of the study was to check if the nature of the lactones was modified according to the altitude of the region where the plants were grown. Among the lactones, five were already described: coronopilin, hymenin, hysterin, parthenin, and tetraneurin A. p-Methoxybenzoic acid and two new ambrosanolides were also detected. Tetraneurin A and hymenin, on the one hand, and parthenin and coronopilin, on the other, were better resolved with a mobile phase of 6% propanol, run during 45 min.