Tenuazonic acid

• (2R )-4- acetyl-2- [( 2R) -butan-2 -yl] -5-hydroxy -1 ,2- dihydro -3-

The data refer to the copper salt.

Risk

The data refer to the copper salt.

• 225 mg · kg -1 ( LD50, mouse, oral)
• 125 mg · kg -1 ( LD50, mouse, i.v.)
• > 50 mg · kg -1 ( LD50, monkey, i.v.)

Template: Infobox chemical / molecular formula search available

Tenuazonsäure is a mycotoxin ( mycotoxin ), which is essentially formed by fungi of the genus Alternaria. Tenuazonsäure is thus a representative from the substance group of tetramic acid derivatives. The systematic chemical name of the chiral molecule is ( 2R)- 4-acetyl- 2-[ (2R) -butan-2 -yl] -5-hydroxy -1 ,2- dihydro -3-one, but frequently also L - Tenuazonsäure or the abbreviation L -TA used.

History

Tenuazonsäure was first isolated in 1958 from an extract of Alternaria tenuis culture. The elucidation of the molecular structure was a year later.

Occurrence

Tenuazonsäure is mainly formed by fungi of the genus Alternaria. However, Piricularia orycae and Phoma sorghina produce this mycotoxin.

Biosynthesis

Experiments 14C- acetate has been demonstrated that in Tenuazonsäure Alternaria tenuis from one molecule of L- isoleucine, and two molecules of acetate, is biosynthesized.

Biological significance and toxicity

Tenuazonsäure has cytotoxic, antibacterial, phytotoxic and anti-viral properties. The biological activity of Tenuazonsäure is due, according to a in-vivo/in-vitro-Studie to the inhibition of protein synthesis, with the release of newly formed proteins from the ribosomes suppressed and the installation of new amino acids into proteins is prevented.

In plants, the inhibition of protein and nucleic acid biosynthesis to leaf blight and brown spot disease leads. In young chicken peroral administration of 1.25 mg per kilogram of body weight Tenuazonsäure 3 weeks caused to clear away organ damage. The LD50 for oral administration in mice 225 mg / kg; after intravenous administration, values ​​of 125 mg / kg ( mice) and > 50 mg / kg ( monkeys) were determined.

Occurrence in food

Because of the widespread occurrence of Alternaria spp. used in food production plants, often can be detected and that formed from this mold mycotoxin Tenuazonsäure in various foods. The following list gives an overview of the foods in which Tenuazonsäure has been already proved:

Add baby food only very low levels were found to Tenuazonsäure. An exception to this products on the basis of millet is that were burdened with very high Tenuazonsäure (130 - 1200 micrograms / kg). The causes of this contamination and the relevance for the consumer's health can be judged at the moment due to the unclear data situation on the toxicology of Tenuazonsäure terrible.

Limits

The legislature has not adopted any limits for Tenuazonsäure.

Analysis

The analysis of Tenuazonsäure, by chromatographic methods such as thin layer chromatography ( TLC), gas chromatography (GC) and high performance liquid chromatography (HPLC) carried out, the latter analysis technique is highly preferred. However, the HPLC analysis of Tenuazonsäure is principally limited by the fact that Tenuazonsäure due to their highly acidic and complexing properties has very poor chromatographic properties. By the addition of zinc sulfate or other modifying additives to the mobile phase, this can be compensated for. As these additives are not suitable for use of a mass spectrometer as a detector (LC -MS), is suitable in those cases, the derivatization of a 2,4- dinitrophenylhydrazone of Tenuazonsäure. This derivatization allows safe and precise determination of Tenuazonsäure in foodstuffs by HPLC coupled with tandem mass spectrometry (LC-MS/MS ). Matrix- dependent variations in the derivatization or ionization in the ion source of the mass spectrometer can be compensated by use of a most stable isotope- labeled internal standards, in the context of a stable isotope dilution assay ( SIVA ). Tenuazonsäure for this is done using [ 13C6, 15N ] - Tenuazonsäure.

A promising approach for direct LC-MS/MS analysis of Tenuazonsäure waiving derivatization works with the addition of ammonium to the mobile phase (pH 7.5), corresponding to a suitable stationary phase, [ 13C2 ] -labeled Tenuazonsäure as internal standard and using the QuEChERS methodology for sample preparation.

Tenuazonsäure can also be analyzed by immunochemical detection techniques. For apple and tomato products for this was an enzyme-linked immunosorbent assay (ELISA ) was developed.

In samples that were very highly contaminated with Tenuazonsäure, could next Tenuazonsäure itself also related compounds derived from the amino acids valine and leucine, are detected.