Origin and chemical structure
Enniatins (ENN) are a group of emerging mycotoxins produced by species of the genus Fusarium. They have a cyclic hexadepsipeptide structure that has three d-2 hydrocarboxylic amino acids and three N-methylamino amino acids linked alternately.
Enniatins have been found predominantly in cereal grains, such as barley, corn, oats, wheat, and rice, but they have also been found in nuts, dried fruit, bananas, Chinese medicinal herbs, and river water. Up to 29 natural analogs of enniatins are known, but only seven (A, A1, A2, B, B1, B2 and B3) have been detected in cereals and their derivatives, and enniatins A, A1, B and B1 are the findings most frequently in food and feed.
Table 1 Functional groups that occupy the R positions in the figure and that determine enniatin.
|TO||sec -butyl||sec -butyl||sec -butyl||CH3||CH3||CH3|
|A1||iso- propyl||sec -butyl||sec -butyl||CH3||CH3||CH3|
|A2||iso- propyl||sec -butyl||iso- propyl||CH3||CH3||CH3|
|B||iso- propyl||iso- propyl||iso- propyl||CH3||CH3||CH3|
|B1||iso- propyl||iso- propyl||sec -butyl||CH3||CH3||CH3|
|B2||iso- propyl||iso- propyl||iso- propyl||H||CH3||CH3|
|B3||iso- propyl||iso- propyl||iso- propyl||H||H||CH3|
|B4||iso- propyl||iso- propyl||iso -butyl||CH3||CH3||CH3|
Since they originate from the same fungal species, enniatins are found concomitantly in food with other Fusarium mycotoxins , such as deoxynivalenol, moniliformin and fumonisins, and especially with beauvericin, another mycotoxin of emerging interest, since, in addition, it also shares the hexadipepsidic structure. This coincidence of origin and structural means that beauvericin is grouped analytically and toxicologically with the enniatins. Furthermore, analytical data show a high concomitance between enniatins and beauvericin in cereal grains.