A quantitative structure-activity relationship study on substituted pyridines as a contribution to the knowledge of the toxic effects of orellanine, a toxin from the mushroom Cortinarius orellanus.

Quantitative structure-activity relationships are established based upon the toxicity of 21 substituted pyridines. They are used as a predictive tool to calculate the toxicity of orellanine, a toxin from the mushroom Cortinarius orellanus (Fries). The actual toxicity of orellanine is quite different from the values calculated based upon the postulated bipyridine structure. The exact structure of orellanine may be questioned. However, our results show that even slight variations of the substituents of pyridines may cause dramatic changes of toxicity.