PAs in Echium vulgare
Boppré M, Colegate SM, Edgar JA (2005) Pyrrolizidine alkaloids of Echium vulgare honey found in pure pollen. J Agric Food Chem 53: 594-600. lesen / read
The pyrrolizidine alkaloids previously identified in floral honey attributed to Echium vulgare (Boraginaceae) have been detected (8000-14000 ppm) in pure pollen collected from the anthers of Echium vulgare. Pyrrolizidine alkaloids and/or their N-oxides were isolated from the aqueous acid extracts of pollen using strong cation exchange, solid phase extraction and identified using LCMS analysis. The pyrrolizidine alkaloids in the pollen are present mainly as the N-oxides. In addition to seven previously described pyrrolizidine alkaloids and/or their N-oxides (echimidine, acetylechimidine, uplandicine, 9-O-angelylretronecine, echiuplatine, leptanthine and echimiplatine), one unidentified (echivulgarine), but previously found in honey, and two previously undescribed (vulgarine and 7-O-acetylvulgarine) pyrrolizidine alkaloids and/or their N-oxides were identified in the pollen. Tentative structures for these unidentified pyrrolizidine alkaloids are proposed based on the mass spectrometric data and biogenetic considerations. The implications of these results for identifying the source and subsequent concentrations of pyrrolizidine alkaloids in honeys and commercial beepollen are briefly discussed.