Stemphyloxin I

Stemphyloxin I is an octahydronaphthalene that is 2,4,5,7-tetramethyloctahydronaphthalen-1(2H)-one which is substituted by hydroxy groups at positions 2 and 7, a (2R)-1-hydroxybutan-2-yl group at position 3, and a (2Z)-3-hydroxyprop-2-enoyl group at position 4 (the 2S,3R,4R,4aS,5R,7R,8aS stereoisomer). Isolated from the endophytic fungus Stemphylium botryosum, it is the causal agent of leaf spot and foliage blight disease in tomatoes. Its phytotoxcity is at least 200 times greater than that of stemphyloxin II. It shows high affinity for Fe3+ (but not Fe2+) ions. It has a role as an iron chelator, a phytotoxin and a fungal metabolite. It is a member of octahydronaphthalenes, an alpha-hydroxy ketone, a 3-oxo aldehyde, a primary alcohol, a tertiary alcohol, a tetrol, an enol and a cyclic ketone.