Enniatin B1

Enniatins (ENs), a group of antibiotics commonly produced by various strains of Fusarium, are six-membered cyclic depsipeptides formed by the union of three molecules of D-α-hydroxyisovaleric acid and three N-methyl-L-amino acids. The endophyte Fusarium tricinctum Corda was isolated from the fruits of Hordeum sativum Jess. and cultivated on a rice medium. The fungal metabolites were extracted with methanol and were identified, employing liquid chromatography-mass spectrometry as ENs A, A1, B, B1, B2 and Q. EN Q is a new analog of EN A and the occurrence of EN B2 is reported for the first time from this endophyte, in addition to four well-known ENs (A, A1, B and B1). The methanol extract of F. tricinctum showed mild antibacterial and antileishmanial activities. Additionally the tested extract displayed inhibition of the activity of thioredoxin reductase enzyme of Plasmodium falciparum.

Hepatotoxicity of three Fusarium mycotoxins, beauvericin (BEA) and two enniatins (ENNs) ENN A1 and ENN B1, in hepatocarcinoma cells (HepG2) were evaluated and compared. Concentrations used were 1.5 and 3 μM at 24, 48 and 72 h for each mycotoxin. Flow cytometry was used to examine enniatins effects on cell proliferation, to characterize the cell cycle phase where the cells blocked and to study the mitochondria role in ENNs-induced apoptosis. ENN B1 treated cells showed a time dependent G1 blockade at both concentrations used. ENN A1 and BEA decreased the apoptotic-necrotic percentage of cells comparing to control and disrupted the MMP as observed by TMRM and ToPro-3 fluorochromes signal. It is proposed a decreasing mycotoxin order by number of effects as follows: BEA > ENN B1 > ENN A1, with 47, 20 and 16%, respectively out of all situations compared.