On the Chemical Nature of the Eczematogenic Agent in Oil of Turpentine

Abstract

The authors have investigated the primary irritant effect of various terpenes, including [alpha]-pinene, [beta]-pinene, [delta]3-carene and limonene. With Rokstad''s adhesive chamber method, slightly modified, the freshly distilled, unoxidized terpenes as a rule elicited toxic reactions at 70-80% concentrations. With oxidation of the terpenes their primary irritant effect increased, on account of the increase in their hydroperoxide content, irrespective of which terpene was concerned. This is in contrast to the eczematogenic effect of oil of turpentine, which is solely or mainly due to the oxidation products (hydroperoxide) of [delta]3-carene. Knowledge of the primary irritant effect of terpene hydroperoxides is essential when the eczematogenic effect of oil of turpentine is investigated. The toxic reactions possibly elicited by the oxidized terpenes at lower concentrations than previously realized may otherwise be erroneously regarded as allergic.