EVALUATION OF THE SENSITIZING POTENTIAL OF EUGENOL AND ISOEUGENOL IN MICE AND GUINEA-PIGS

The sensitizing properties of the fragrances eugenol and isoeugenol ha ve been investigated experimentally. The potential of these materials to induce sensitization of the respiratory tract was examined using th e mouse IgE test, a novel but as yet unvalidated method for the predic tive identification of chemical respiratory allergens. Comparisons wer e made with the activity of eugenol and isoeugenol in two predictive t ests for contact sensitization potential: the murine local lymph node assay and the guinea pig maximization test. Both chemicals elicited po sitive responses in these tests, isoeugenol exhibiting a greater poten tial for contact sensitization than eugenol. Isoeugenol was negative a t all concentrations examined in the mouse IgE test. In the same assay , exposure to eugenol was associated with a statistically significant increase in serum IgE concentrations when initial application concentr ations of 2.5% were used. However, at higher test concentrations eugen ol was negative in the mouse IgE test. It is concluded that neither eu genol nor isoeugenol have a significant potential to cause sensitizati on of the respiratory tract, a conclusion that is apparently consisten t with the lack of evidence for occupational respiratory allergy assoc iated with exposure to these chemicals. The evidence for isoeugenol la cking respiratory sensitization activity is particularly strong and it is proposed that this chemical may be of value as a negative control in the development and validation of new predictive test methods for t he identification of chemical respiratory allergens.