title: Detection and Quantitative Analysis of the Non-cytotoxic allo-Tenuazonic Acid in Tomato Products by Stable Isotope Dilution HPLC-MS/MS.
abstract: Tenuazonic acid (1) is a mycotoxin produced mainly by fungi of the genus Alternaria. It occurs in a variety of agricultural products. allo-Tenuazonic acid (2) is an isomer of 1 that is not chromatographically separated from 1 in most analytical methods. Therefore, both isomers are quantitated as a sum parameter. In this study a QuEChERS (quick, easy, cheap, effective, rugged and safe) based stable isotope dilution HPLC-MS/MS method including the chromatographic separation of both isomers was developed and applied to 20 tomato products from the German market. All products showed contamination with both toxins. 1 was found in a range from 5.3 ± 0.1 to 550 ± 15 μg/kg (average = 120 μg/kg) and 2 in a range from 1.5 ± 0.4- to 270 ± 0.8 μg/kg (average = 58 μg/kg). 2 represents 7.0-44% of the sum of both isomers (average = 29%). This is the first reported occurrence of 2 in food samples. To evaluate and compare the cytotoxicities of 1 and 2, both compounds were isolated from a synthetic racemic mixture. 1 showed moderate cytotoxic effects on HT-29 cells starting at 100 μM, whereas 2 exhibited no activity. 2 was not produced in liquid cultures of Alternaria alternata in yeast extract sucrose (YES) medium, but could be detected in small amounts in tomato puree inoculated with the fungus.
authors.affiliation: Institute of Food Chemistry, Westfälische Wilhelms-Universität Münster , Corrensstraße 45, 48149 Münster, Germany.|NRW Graduate School of Chemistry , Wilhelm-Klemm-Strasse 10, 48149 Münster, Germany.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Hickert
authors.affiliation: Institute of Food Chemistry, Westfälische Wilhelms-Universität Münster , Corrensstraße 45, 48149 Münster, Germany.
authors.forename: Isabel
authors.initials: I
authors.lastname: Krug
authors.affiliation: Institute of Food Chemistry, Westfälische Wilhelms-Universität Münster , Corrensstraße 45, 48149 Münster, Germany.
authors.forename: Benedikt
authors.initials: B
authors.lastname: Cramer
authors.affiliation: Institute of Food Chemistry, Westfälische Wilhelms-Universität Münster , Corrensstraße 45, 48149 Münster, Germany.|NRW Graduate School of Chemistry , Wilhelm-Klemm-Strasse 10, 48149 Münster, Germany.
authors.forename: Hans-Ulrich
authors.initials: HU
authors.lastname: Humpf
mesh_terms: D002470:Cell Survival / Q000187:drug effects; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D005506:Food Contamination / Q000032:analysis; D005511:Food Handling / Q000379:methods; D005638:Fruit / Q000737:chemistry*; D005858:Germany; D019073:HT29 Cells; D006358:Hot Temperature; D006801:Humans; D007201:Indicator Dilution Techniques; D007536:Isomerism; D057230:Limit of Detection; D018551:Solanum lycopersicum / Q000737:chemistry*; D053719:Tandem Mass Spectrometry / Q000379:methods*; D013720:Tenuazonic Acid / Q000032:analysis* / Q000302:isolation & purification / Q000633:toxicity*
chemical_list: D013720:Tenuazonic Acid
keywords: alternaria; cytotoxicity; liquid chromatography; mass spectrometry; mycotoxin; stable isotope dilution assay