esculetin and Dermatitis--Contact

9 coumarins used as chemical reagents, laser dyes, in perfumery, cosmetics or occurring naturally, were investigated experimentally in guinea pigs to determine their contact sensitizing capacity. 5,7-dihydroxycoumarin, limettin and 5,7-dihydroxy-4-methylcoumarin were found to be moderate sensitizers, while scoparone, isoscopoletin and 4-hydroxycoumarin were weak. The 3 laser dyes were completely negative. The results indicate that substitution in the 6 and 7 or 5 and 7 positions with 2 hydroxy groups supports allergenic capability, while other substituents (e.g., methoxy groups) in the same positions, or an additional (third) substituent, diminish activity.

Topics: 4-Hydroxycoumarins; Animals; Coloring Agents; Cosmetics; Coumarins; Dermatitis, Contact; Drug Eruptions; Female; Guinea Pigs; Lasers; Perfume; Scopoletin; Umbelliferones

5 coumarins used in perfumery, cosmetics, therapeutic ointments or occurring naturally were investigated by Freund's complete adjuvant technique (FCAT) in guinea pigs to determine their contact sensitizing potency. 4-Methylesculetin was also studied. Esculetin, dihydrocoumarin and daphnetin were found to be moderate to strong sensitizers, while fraxetin was nearly and 7-methylcoumarin completely inactive. The results corroborate the hypothetical view that only those coumarins having a catecholic disubstitution in the benzene ring, e.g., esculetin, 4-methylesculetin, daphnetin, can become sensitizers on the basis that they are capable of forming ortho-quinones under oxidizing conditions.

Topics: Animals; Cosmetics; Coumarins; Cross Reactions; Dermatitis, Contact; Female; Freund's Adjuvant; Guinea Pigs; Immunization; Skin Tests; Structure-Activity Relationship; Umbelliferones