Evaluation of allergenicity of constituents of myoga using the murine local lymph node assay.

Myoga (Zingiber Myoga Roscoe) is a perennial plant with a pungent smell from its flower buds. It is native to East Asia and has been reported to cause allergic contact dermatitis. The purpose of this study is to assess the allergenicity of myoga related to its major chemical components, alpha-pinene, beta-pinene, limonene, limonene oxide and beta-phellandrene, which are supposed to be the causative agents of contact dermatitis among myoga cultivators. We performed a toxicity study of the volatile constituents of myoga using the local lymph node assay (LLNA), in which limonene, limonene oxide and beta-phellandrene had positive responses and the EC3 was 35.8%, 8.22%, and 0.54%, respectively. EC3 for both alpha-pinene and beta-pinene was over 100%. Both chemicals failed to induce positive responses in the LLNA. While the maximization rating of limonene, limonene oxide and phellandrene were evaluated as moderate, extreme, and extreme respectively, alpha-pinene and beta-pinene were evaluated as weak in the previously reported GPMT. The usage of LLNA was also confirmed by comparing with previously reported GPMT results to detect the allergenicity of myoga constituents. The actual risk of humans developing an allergy to myoga constituents depends on many factors. The concentration of the compounds, the frequency and duration of exposure and the condition of the skin are supposed to be important factors.