Formation of novel toxic compounds from oxidative interaction between salsolinol and cysteine.

The electrochemically-driven oxidation of salsolinol (SAL) precedes via a 2e, 2H+ process to produce the corresponding o-quinone (E) intermediate which has a very short lifetime and can be scavenged by cysteine to give the corresponding adduct cysteinyl salsoninol (F). F is more easily oxidized to the corresponding o-quinone (G) followed by cyclization resulting in the formation of the quinone imine intermediate (H). H can then undergo series of nucleophilic addition and oxidation reactions to produce a very complicated mixture of products including some dihydrobenzothiazines. Six of these products have been isolated and identified. Central administration of these compounds into laboratory mice revealed that three of them are fairly toxic and evoke profound behavioral responses.