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Determination of ptaquiloside and pterosin B derived from bracken (Pteridium aquilinum) in cattle plasma, urine and milk

Aranha, Paulo César Reis, Hansen, Hans Christian Bruun, Rasmussen, Lars Holm, Strobel, Bjarne W., Friis, Christian
Journal of Chromatography B 2014 v.951-952 pp. 44-51
Pteridium aquilinum, ambient temperature, genotoxicity, heifers, hydrolysis, indans, intravenous injection, liquid chromatography, mass spectrometry, milk, ptaquiloside, urine
Ptaquiloside (PTA) is a toxin from bracken fern (Pteridium sp.) with genotoxic effects. Hydrolysis of PTA leads to the non-toxic and aromatised indanone, pterosin B (PTB). Here we present a sensitive, fast, simple and direct method, using SPE cartridges to clean and pre-concentrate PTA and PTB in plasma, urine and milk followed by LC–MS quantification. The average recovery of PTA in plasma, urine, and milk was 71, 88 and 77%, respectively, whereas recovery of PTB was 75, 82 and 63%. The method LOQ for PTA and PTB in plasma was 1.2 and 3.7ngmL−1, 52 and 33ngmL−1 for undiluted urine and 5.8 and 5.3ngmL−1 for milk. The method is repeatable within and between days, with RSD values lower than 15% (PTA) and 20% (PTB). When PTA and PTB spiked samples were stored at −18°C for 14 days both compounds remained stable. In contrast, the PTA concentration was reduced by 15% when PTA spiked plasma was left for 5h at room temperature before SPE clean-up, whereas PTB remained stable. The method is the first to allow simultaneous quantification of PTA and PTB in biological fluids in a relevant concentration range. After intravenous administration of 0.092mg PTA per kgbw in a heifer, the plasma concentration was more than 300ngmL−1 PTA and declined to 9.8ngmL−1 after 6h, PTB was determined after 10min at 50ngmL−1