Pyrrolizidine Alkaloids in the Food Chain: Development, Validation, and Application of a New HPLC-ESI-MS/MS Sum Parameter Method

Abstract

Contamination of food and feed with pyrrolizidine alkaloids is currently discussed as a potential health risk. Here, we report the development of a new HPLC-ESI-MS/MS sum parameter method to quantitate the pyrrolizidine alkaloid content in complex food matrices. The procedure was validated for honey and culinary herbs. Isotopically labeled 7-O-9-O-dibutyroyl-[9,9-(2)H2]-retronecine was synthesized and utilized as an internal standard for validation and quantitation. The total pyrrolizidine alkaloid content of a sample is expressed as a single sum parameter: retronecine equivalents (RE). Ld/Lq for honey was 0.1 μg RE/kg/0.3 μg RE/kg. For culinary herbs, 1.0 μg RE/kg/3.0 μg RE/kg (dry weight, dw) and 0.1 μg RE/kg/0.3 μg RE/kg (fresh weight, fw) were determined, respectively. The new method was applied to analyze 21 herbal convenience products. Fifteen products (71%) were pyrrolizidine alkaloid positive showing pyrrolizidine alkaloid concentrations ranging from 0.9 to 74 μg RE/kg fw.

Determination of Pyrrolizidine Alkaloids in Honey with Sensitive Gas Chromatography-Mass Spectrometry Method

“…The elution was relatively fast and possible to carry out without the use of back pressure. Cramer et al, 2013 eliminated the N-oxide zinc reduction step by increasing the amount of LiAlH 4 and also decreased the time of refrigeration and confirmed the efficiency of reduction of PAs to the backbone structure experimentally. However, it was observed that the zinc reduction step reduces the viscosity of the honey extract.…”

“…1) and expressed as single sum parameter value. The advantages and disadvantages of the sum parameter method have been already described in details (Kempf et al 2008;Cramer et al 2013;Kowalczyk and Kwiatek 2017).…”

“…After evaporation at 40°C in a nitrogen stream, the residues were reconstituted in 3 ml of ethyl acetate with an addition of 100 μl of MeOH and transferred into smaller vials and evaporated again. The reduction of the alkaloids was performed according to Kempf and Crammer (Kempf et al 2008;Cramer et al 2013) with some modifications. First, 10 μl of MeOH was added to solubilize the residue and subsequently 500 μl of LiAlH 4 1 M solution in THF, and the samples were kept in a refrigerator for an hour.…”

Public and private standards for dried culinary herbs and spices—Part I: Standards defining the physical and chemical product quality and safety

“…In recent years, contaminations with PAs could be detected, among other product groups, in herb products. Next to herbal teas and herbal food supplements they were also detected in culinary herb mixes (Cramer, Schiebel, Ernst, & Beuerle, 2013). The star anise, also called Chinese star anise (derived from Illicium verum) is used as culinary spice and for herbal teas.…”

The Chemical Profile of Pyrrolizidine Alkaloids from Selected Greek Endemic Boraginaceae Plants Determined by Gas Chromatography/Mass Spectrometry

“…In addition to GC/MS, HPTLC (13) and ELISA (14) methods that have been lately reported for the qualitative detection of PAs, LC/MS is among the main methods used for qualitative and quantitative analysis (15)(16)(17). In LC/MS protocols, N-oxides are usually reduced and consequently selectively retained by strong cation exchange (SCX) SPE cartridges, from which they are eluted with ammoniated methanol (17)(18)(19).…”