A Miniaturized QuEChERS Method Combined with Ultrahigh Liquid Chromatography Coupled to Tandem Mass Spectrometry for the Analysis of Pyrrolizidine Alkaloids in Oregano Samples

Abstract

Recent and unexpected food alerts about relatively high amounts of pyrrolizidine alkaloids in oregano samples have stressed the need to develop analytical strategies to ensure food safety in this type of foodstuff. Accordingly, this work presents the development of a miniaturized strategy based on the QuEChERS (quick, easy, cheap, effective, rugged and safe) method combined with ultrahigh liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS) for the determination of 21 pyrrolizidine alkaloids suggested by the European Food Safety Authority to be monitored in food. The analytical method was properly validated, with overall average recoveries from 77 to 96% and relative standard deviations <13% (n = 9). The method proved to be a sustainable analytical strategy which meets green analytical chemistry principles as it showed good performance by using small amounts of sample (0.2 g), organic solvents (1000 µL), clean-up sorbents (175 mg) and partitioning salts (0.65 g). Its feasibility was verified through the analysis of 23 oregano samples. Of the samples analyzed, 100% were contaminated, with an average concentration of 1254 µg/kg. Lasiocarpine, lasiocarpine N-oxide, europine, europine N-oxide, senecivernine, senecionine, echimidine N-oxide, lycopsamine N-oxide and intermedine N-oxide were the alkaloids which significantly contributed to the contamination of the samples.

Determination of pyrrolizidine alkoloids in oregano (Origanum onites) produced in Denizli by LC-MS Q-TOF method

“…Izcara ve ark. (30), tarafından UHPL-MS/MS ile birleştirilmiş QuEChERS yöntemiyle 21 farklı PA'nın incelendiği bir çalışmada ise 23 oregano örneğinin tamamının ortalama 1254 µg/kg PA ile kontamine olduğu ve örneklerin % 30'unda sınır değeri (1000 µg/g) aştığı bildirilmektedir. Örneklerin tamamında saptanan europin, europin N-oksit miktarının çalışma bulgularından çok yüksek olduğu görülmektedir.…”

“…Ayrıca, saptanan PA'ların geniş çeşitlilikte olması oregano örneklerinin, Boraginaceae ve Asteraceae familyalarından çok farklı yabani bitkilerle kontamine olduğunu işaret etmektedir. Genel olarak sonuçlarda, tüketiciler için potansiyel sağlık riskleri oluşturacak düzeyde PA saptanması, aromatik bitkilerin tamamında bu bileşiklerin varlığının izlenmesi ve ilgili önlemlerin alınması gerekliliğini vurgulamaktadır (29,30).…”

Mesostructured Silicas as Cation-Exchange Sorbents in Packed or Dispersive Solid Phase Extraction for the Determination of Tropane Alkaloids in Culinary Aromatics Herbs by HPLC-MS/MS

“…In addition, most of the aromatic herbs (for example, thyme, basil and coriander) are valuable as ingredients in infusions with a variety of uses, such as digestive, antispasmodic, antitussive, antidiarrheal, antiemetic, or anthelmintic [ 6 ]. Despite the beneficial properties of aromatic herbs, such as condiments and/or herbal infusions, the occurrence of some natural toxins in these foods, such as tropane alkaloids [ 7 ], pyrrolizidine alkaloids [ 8 ] or alkenylbenzenes [ 9 ], among others, should be controlled. Concerning alkaloids, contamination of aromatic herbs occurs mainly due to accidental co-harvesting of these herbs together with toxic plants or by horizontal natural transfer from alkaloid-containing living plants or plant material through the soil [ 8 , 9 ].…”

Pyrrolizidine Alkaloids in the Food Chain: Is Horizontal Transfer of Natural Products of Relevance?

“…To date, many cases of human and livestock poisonings are recorded in literature as a result of food, phytomedicines, or feed contamination with secondary metabolites of toxic plants such as pyrrolizidine alkaloids (PAs), cardiac glycosides or other toxic compounds [1,2]. In the case of PAs, these toxins are introduced mainly by accidental co-harvesting of poisonous PA plants together with the crop of interest [3].…”

“…Similar observations are known for xe- So far, accidental or unwanted co-harvesting has been identified as the main source of PA-contamination potentially harmful to humans or livestock as a result of mixing leaves of plants that contain PAs with leaves of medicinal herbs or teas [12] or of mixing the seeds of PA-plants with wheat and barley crops [13]. Commercial fraud and mixing medicinal herbs with other plants to meet price, volume, or other market demands, might be another source for this contamination [2]. In addition, flowers, with their contents of nectar and pollen, are by now a well-known cause of food contamination with PAs [14].…”