Preparative mass-spectrometry profiling of genotoxic pyrrolizidine alkaloids in Jacobaea vulgaris (syn. Senecio jacobaea) by spiral-coil countercurrent chromatography and ESI-MS/MS off-line continuous injection

Pyrrolizidine alkaloids (PAs) are genotoxic natural products. Almost 350 PAs are known with respective N-oxides. Legal regulations of PAs in food, and feed are discussed. There is a lack of available reference substances for targeted quantification [1]. PA-contamination was reported for honey, and bee products [2,3]. PA-contamination of retail ready-to-use lettuce was demonstrated. Morphological similarities of rocket salad (Diplotaxis tenuifolia, syn.: rucola), and the PA-plant Senecio vulgaris resulted in unintentional co-harvesting. In our study, PA-extract of J. vulgaris flower heads (Asteraceae) was fractionated by prep. spiral-coil countercurrent chromatography (spCCC, 5.7 L coil). The system n-hexane – EtOAc – MeOH – H2O (3:7:5:5) was used to separate 5 g of crude alkaloid extract. Obtained fractions were sequentially off-line injected to ESI-MS/MS. This target-guided isolation procedure [4] made use of selected ion traces of PAs. Elution of major (2, 5, 7), and minor (1, 3, 4, 6) PAs were monitored (altern. mode MS2, m/z 100 – 1500). The spCCC elution resulted in the fractionation of PAs, and one non-PA (8) in the extrusion-mode (8 not presented) [5]. Almost pure compounds were obtained for PAs 1, 2, 5, 7, and the non-PA 8 could be used as reference materials. Minor PAs were enriched and will be further purified with other separation techniques.