| The aim of this work was to develop a phytochemical screening method for some selected carcinogenic or tumor-promoting principles in higher plants. The pyrrolizidine alkaloids from some Senecio species (Compositae or Asteraceae), and the diterpene esters from Croton tiglium L. and Euphorbia ingens E.Mey (Euphorbiaceae) were chosen as representatives of both groups.;The possibilities and limitations of 1H and 13C nuclear magnetic resonance spectroscopy (1H and 13C NMR) for the analysis of mixtures of carcinogenic pyrrolizidine alkaloids were compared with high performance liquid chromatography, and gas chromatography as well as gas chromatography--mass spectrometry. Senecio vulgaris L., Senecio vernalis Waldst. & Kit. and Senecio jacobaea L. were investigated.;For the isolation and the chromatographic separation of the diterpene esters rotation locular countercurrent chromatography (RLCC) and vacuum liquid chromatography (VLC) were used. RLCC was a suitable method to isolate phorbol esters from croton oil, the seed oil of Croton tiglium, and to separate at the same time the tumor-promoting phorbol 12,13-diesters from the cryptic tumor-promoting 12,13,20-triesters. VLC was used for the isolation and the separation of the different groups of phorbol 12,13-diesters from the diester fraction, obtained by a preliminary RLCC experiment. 1H NMR was an interesting method for the identification and the quantification of phorbol esters in mixtures, in semi-purified samples, or even in the complete croton oil, and it was possible to determine at the same time the proportion of diesters and triesters. VLC was a suitable method for the isolation of the diterpene esters from Euphorbia ingens E.Mey as well. It was possible to measure separately the total ingenol ester level, the amount of tumor-promoting ingenol 3-esters, the amount of biologically inactive ingenol 20-esters, and the total ingol ester level using 1H NMR. |
