High abundance of pyrrolizidine alkaloids in bee pollen collected in July 2019 from Southern Germany

Pyrrolizidine alkaloids (PA) are secondary plant defense compounds and known pre-toxins when containing a 1,2-double bond. They are commonly produced by various plants and may thus be present in bee pollen which may be consumed by humans as food supplements. In this study, PA were determined in bee pollen samples from 57 locations in Southern Germany sampled by means of pollen traps in July 2019. Samples were analyzed by using palynological methodology and solid-phase extraction (SPE) followed by LC-MS/MS. In total, 52 pollen samples featured total pyrrolizidine alkaloids (Sigma PA) with concentrations up to 48,000 ng/g bee pollen, while the N-oxides (NO) echinatine-NO and rinderine-NO clearly dominated. In contrast, the palynological analysis only detected 33 samples with pollen from PA-producing plants. Accordingly, the results showed that palynological analysis is not sufficient to determine PA in pollen. In addition, a risk assessment was followed to estimate the risk of the detected PA concentrations to humans.

Automated summary

A study was conducted to analyze pyrrolizidine alkaloids (PA) in bee pollen samples from 57 locations in Southern Germany. It was found that 52 out of the collected samples contained PA, with concentrations up to 48,000 ng/g bee pollen. The dominant PA compounds were echinatine-NO and rinderine-NO. However, palynological analysis alone was not sufficient for the determination of PA in pollen. Furthermore, a risk assessment was performed to estimate the potential risk to humans posed by the detected PA concentrations.