title: Quantification of the emetic toxin cereulide in food products by liquid chromatography-mass spectrometry using synthetic cereulide as a standard.
abstract: Bacillus cereus produces the emetic toxin cereulide, a cyclic dodecadepsipeptide that can act as a K(+) ionophore, dissipating the transmembrane potential in mitochondria of eukaryotic cells. Because pure cereulide has not been commercially available, cereulide content in food samples has been expressed in valinomycin equivalents, a highly similar cyclic potassium ionophore that is commercially available. This research tested the biological activity of synthetic cereulide and validated its use as a standard in the quantification of cereulide contents in food samples. The synthesis route consists of 10 steps that result in a high yield of synthetic cereulide that showed biological activity in the HEp-2 cell assay and the boar sperm motility assay. The activity is different in both methods, which may be attributed to differences in K(+) content of the test media used. Using cereulide or valinomycin as a standard to quantify cereulide based on liquid chromatography-mass spectrometry (LC-MS), the concentration determined with cereulide as a standard was on average 89.9% of the concentration determined using valinomycin as a standard. The recovery experiments using cereulide-spiked food products and acetonitrile as extraction solute showed that the LC-MS method with cereulide as a standard is a reliable and accurate method to quantify cereulide in food, because the recovery rate was close to 100% over a wide concentration range.
authors.affiliation: Wageningen University and Research Centre, Laboratory of Food Microbiology, EV Wageningen, Netherlands. els.biesta-peters@wur.nl
authors.forename: Elisabeth G
authors.initials: EG
authors.lastname: Biesta-Peters
authors.forename: Martine W
authors.initials: MW
authors.lastname: Reij
authors.forename: Richard H
authors.initials: RH
authors.lastname: Blaauw
authors.forename: Paul H
authors.initials: PH
authors.lastname: In 't Veld
authors.forename: Andreja
authors.initials: A
authors.lastname: Rajkovic
authors.forename: Monika
authors.initials: M
authors.lastname: Ehling-Schulz
authors.forename: Tjakko
authors.initials: T
authors.lastname: Abee
mesh_terms: D000818:Animals; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D002853:Chromatography, Liquid / Q000379:methods* / Q000592:standards; D047630:Depsipeptides / Q000032:analysis* / Q000138:chemical synthesis / Q000633:toxicity; D004639:Emetics / Q000032:analysis* / Q000138:chemical synthesis / Q000633:toxicity; D005504:Food Analysis / Q000379:methods*; D022781:Hepatocytes / Q000187:drug effects; D006801:Humans; D008124:Locomotion / Q000187:drug effects; D008297:Male; D013058:Mass Spectrometry / Q000379:methods* / Q000592:standards; D012015:Reference Standards; D013094:Spermatozoa / Q000187:drug effects; D034421:Sus scrofa
chemical_list: D047630:Depsipeptides; D004639:Emetics; C089294:cereulide