Pyrrolizidine alkaloids and relative N-oxides evaluation in Italian honey from the Veneto region (Italy) by LC-MS/MS.

Pyrrolizidine alkaloids (PAs) are the most common class of natural toxins (approximately 350 types), synthesised by a wide variety plant species and the presence of PAs in food and feed clearly represents a potential risk to human and animals. In this study, an analytical method by liquid chromatography coupled to mass spectrometry (LC-MS/MS) was applied to evaluate and characterise PA and their N-oxides (PANOs) content in Italian honey. Echimidine, heliotrine, lycopsamine, senecionine, seneciphylline, retrorsine and the corresponding PANOs were considered. For the matrix clean-up and the extraction of PAs/PANOs, the solid phase extraction with non-polar/cation-exchange polymeric cartridges, PLEXA 200 mg/6 mL, (Agilent Technologies, USA) were adopted. Analyses were performed by a LTQ XL ion trap, equipped with a heated electrospray ionisation probe, operating in positive ion mode (Thermo Fischer Scientific, San Jose, CA, USA). The linearity of the calibration curves was evaluated in the range of 0.25-50 ug kg-1, the mean recovery ranged from 82.70 % to 104.16 %; LOQ was 0.25 ug kg-1 for all PAs/PANOS, fully satisfying the limit stated in the document “Summary report of the standing committee on plants, animals, food and feed held in Brussels on 1 July 2014”. 147 honey samples from Veneto region were analysed, according to their geographical origin. Analyses showed that 69% of the honey samples were negative for all PAs/PANOs monitored, 31% were positive. In all positive samples the contribute from target PANOs was negligible (range 0.39-1.52 µg kg-1). The total content of PAs/PANOs monitored in Veneto honey ranged from 0.25 to 64.44 µg kg-1. These results are not consistent with previous studies about honey samples from other European countries. Taking into account the indication from CONTAM Panel (EFSA 2011), based on the Margin of Exposure (MOE) approach, a honey sample must not exceed a PAs/PANOs total content of 21 µg kg-1; only 9% of our samples exceed this limit. Moreover, preliminary results showed an influence of two important factor as season (summer > spring) and territory (hills > lowland) on the total content of PAs/PANOs in honey. Honey produced from local beekeepers of Veneto region is not a real threat to health, while a monitoring program of PAs/PANOs in honey is highly desirable to risk assessment.