The major allergen of Dendropanax trifidus Makino

Dendropanax trifidus Makino (family Araliaceae, syn. Gilibertia trifida Makino) has been reported as causing allergic contact dermatitis in Japan. To identify the major allergen, fractionated extracts of fresh leaves of Dendropanax trifidus were patch tested on 2 patients with hypersensitivity to the plant. Cis-9,17-octadecadiene-12,14-diyne-1, 16-diol (I), an analog of falcarinol, was identified as an active component. 18 normal control subjects were patch tested with the leaf of Dendropanax trifidus and I diluted to 0.05% in pet. 4 of them showed active sensitization to the leaf of Dendropanax trifidus and I. Our results suggest that I is the major allergen of Dendropanax trifidus and is a strong sensitizer. The results of patch testing on patients and control subjects with the leaves of Fatsia japonica Decne. et Planch. and Hedera helix L., which also belong to the Araliaceae family, and urushiol are also shown.