Orellanin

From Freepedia

In 1955 the Polish physician Grzymała isolated a substance from the fungus Cortinarius orellanus. After the Latin name of this toadstool, he named it orellanine. Given orally research animals, he got the same reaction as in humans, damage of the kidneys. However, the chemical constitution remained unknown until the Polish chemists Antkowiak and Gessner in the last half of the 1970s discovered that it belongs to a group of compounds called bipyridines, a double ring structure where both rings are principally a pyridine ring (a heterocyclic ring with one nitrogen atom). They also came across a new, but similar substance, orelline. However, in spite of its close chemical structure, orelline is not toxic. In the most stable form of orellanine, the nitrogen atoms are positively charged. (This is not the case for orelline that is neutral in its most stable form.)

Bipyridines with positively charged nitrogen atoms were already before the structure of orellanine was elucidated known to be poisonous. The herbicides paraquat and diquat are toxic not only to plants, but also to animals including man. The main mechanism of bipyridines with charged nitrogen atoms is that they confound important red-ox reactions in organisms, ‘stealing’ one or two electrons and sometimes bypass the electrons into other and often undesirable red-ox reactions. The terminal product can be peroxide or superoxide ions. Specially, the last ion is harmful to the cells. Probably, orellanine works in the same way, although the way from disturbed red-ox reactions to the serious clinical kidney damage has not been properly resolved.

Orellanine has also been found in Cortinarius rubellus.