THE DESTRUCTION BY TYROSINASE OF THE IRRITANT PRINCIPLES OF POISON IVY AND RELATED TOXICANTS

¹ From the Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts

Purified mushroom tyrosinase catalyzes the oxidation of the toxic principles of a large number of different commercial poison ivy concentrates, as well as extracts of related materials from poison oak, Japanese lac and cashew nut shell liquid. It has a similar action upon the purified toxicants: urushiol, 3-geranyl catechol, anacardol, tetrahydro-anacardol, anacardic acid, tetrahydro-anacardic acid and cardanol. These irritant materials slowly autoxidize, even in the absence of tyrosinase. The action of tyrosinase in the oxidation of the phenolic groups of these toxicants has been studied by oxygen consumption measured manometrically, by a darkening in color during oxidation and by a disappearance of phenolic groups reactive with ferric chloride.

Accompanying the oxidation of these toxic materials by tyrosinase there is an appreciable decrease in the dermatitis-producing properties as measured by using both human and guinea pig skin patch tests. Tyrosinase is effective in the inactivation of the toxicants not only in vitro but also when applied to the human skin simultaneously with the toxicants or a few hours after they have penetrated into the skin. The use of tyrosinase in the treatment of poison ivy dermatitis in its early stages is suggested, although no information is as yet available concerning the utilization of this enzyme for the inactivation of the toxicants in the more advanced stages of the dermatitis.