Int Immunopharmacol. 2002 Jun; 2(7): 901-11.

Effect of orally administered Hochu-ekki-to, a Japanese herbal medicine, on contact hypersensitivity caused by repeated application of antigen.

Nakada T, Watanabe K, Matsumoto T, Santa K, Triizuka K, Hanawa T.

Oriental Medicine Research Center of the Kitasato Institute, Tokyo, Japan.

The effects of oral administration of Hochu-ekki-to (HET; bu-zhong-yi-qi-tang in Chinese), a traditional Japanese and Chinese herbal medicine, on chronic contact hypersensitivity were investigated. HET suppressed ear swelling due to chronic contact hypersensitivity caused by repeated application of 2,4,6-trinitro-1-chlorobenzene (TNCB). HET significantly suppressed not only increases in hapten-specific immunoglobulin E (IgE) and IgG1 titer due to repeated application of TNCB, but also total IgE and IgG1 concentration in the serum. Interleukin 4 (IL-4) level in inflamed ear tissue was significantly increased by repeated application of TNCB, and this increase in IL-4 level in the ear was significantly suppressed by oral administration of HET. Interferon gamma (IFN-gamma), IL-2, IL-5, IL-10 and IL-12 levels are not changed as much as IL4 by TNCB and HET did not alter these cytokines as much as IL-4. These results suggest that oral administration of HET suppresses chronic contact hypersensitivity, and it can be assumed that the suppression of serum Ig E and Ig G1 and IL-4 in inflamed ear.