2-Amino-14,16-dimethyloctadecan-3-ol: in vitro bioactivity and bio-production by the fungus Fusarium avenaceum

2-Amino-14,16-dimethyloctadecan-3-ol (2-AOD-3-ol) belongs to the class of sphingosine analogue toxins, which is a class of toxins that is known among several fungal genera and some lower marine animals. Many sphingosine analogues have been shown to inhibit ceramide synthase through structural similarities with the substrates of the enzyme. The adverse effects of some analogues, e.g. the fumonisins, are a result of ceramide synthase inhibition. The primary aim of this work was to generate basic knowledge on the toxicity of 2-AOD-3-ol in vitro. The human hepatocarcinoma cell line Hep G2 and horse erythrocytes were used in order to achieve this aim. The second aim of this work was to gain insight into the capabilities of the fungus Fusarium avenaceum, a common contaminant of grain in Scandinavia, to produce the toxin under laboratory conditions on different grain species, and in the field. The metabolite was found to be cytotoxic in several assays (lower µM-range) that measure general cytotoxicity (Alamar Blue" assay, Neutral Red uptake, LDH leakage), but did not inhibit ceramide synthase as measured by the increase of the sphinganine/sphingosine ratio. The cellular membrane was likewise not found to be a primary target of the molecule. Strains of F. avenaceum produced up to 6.3 mg/g of 2-AOD-3-ol on wheat grain under controlled conditions in the laboratory, while only low amounts (