Synthesis and anthelmintic activity of cyclohexadepsipeptides with cyclohexylmethyl side chains

Beauvericin and Enniatins: In Vitro Intestinal Effects

Food and feed contamination by emerging mycotoxins beauvericin and enniatins is a worldwide health problem and a matter of great concern nowadays, and data on their toxicological behavior are still scarce. As ingestion is the major route of exposure to mycotoxins in food and feed, the gastrointestinal tract represents the first barrier encountered by these natural contaminants and the first structure that could be affected by their potential detrimental effects. In order to perform a complete and reliable toxicological evaluation, this fundamental site cannot be disregarded. Several in vitro intestinal models able to recreate the different traits of the intestinal environment have been applied to investigate the various aspects related to the intestinal toxicity of emerging mycotoxins. This review aims to depict an overall and comprehensive representation of the in vitro intestinal effects of beauvericin and enniatins in humans from a species-specific perspective. Moreover, information on the occurrence in food and feed and notions on the regulatory aspects will be provided.

Cyclodepsipeptides: a rich source of biologically active compounds for drug research

Faced with the need to find new drugs for all kinds of diseases, science sees that Nature offers numerous classes of compounds showing an impressively high biological potential. Among those are the cyclodepsipeptides, hybrid structures composed of amino and hydroxy acids. In the past decades numerous cyclodepsipeptides have been isolated and their potential as drugs has been studied extensively. For several cyclodepsipeptides total syntheses both in solution and on solid-phase have been established, allowing the production of combinatorial libraries. In addition, the biosynthesis of specific cyclodepsipeptides has been elucidated and used for the chemoenzymatic preparation of nonnatural analogues. This review summarizes the recent literature on cyclic tetra- to decadepsipeptides, composed exclusively of α-amino- and α-hydroxy acids.

Beauvericin and enniatin: emerging toxins and/or remedies?

Beauvericin (BEA) and enniatins (ENN) are emerging Fusarium mycotoxins that are known to contaminate food and feed. BEA- and ENN-mediated cytotoxicity towards various mammalian and cancer cell lines is only partly understood yet and engages several cellular targets and molecular mechanisms. Thus, the channel forming ability of BEA and ENN selectively directs a flux of cations – particularly calcium – into the cell. The resulting increased intracellular calcium levels might be at least in part responsible for their cytotoxicity. Additionally, BEA and ENN activate programmed cell death via the internal mitochondrial pathway (release of cytochrome c, activation of pro-apoptotic proteins such as Bax and activation of caspases). Several cellular signalling pathways and regulators are influenced by these fusariotoxins including MAPK, NF-κB and p53. The in vitro cytotoxicity implicates that these compounds could be potentially used as cancer therapeutics. However, considering their high prevalence in grains destined for consumption, also potential systemic toxicity towards humans and animals has to be considered. Interestingly, the few studies that have addressed this issue in animals so far predominantly reported minor effects at least as far as acute toxicity is concerned. However, consequences especially of chronic exposure but also at pharmacologically active doses in humans/animals have not been explored in detail. Nevertheless, both compounds exhibit interesting pharmacological characteristics (as they are cytotoxic especially to cancer cells, inhibit drug efflux pumps, are non-mutagenic, inhibit bone resorption) which suggest them as potential drug candidates to fight disseminated cancer. Thus, detailed studies on the consequences of chronic and bolus BEA and ENN exposure are eagerly needed.