Immunological restoration and anti-tumor effect by Japanese herbal medicine in aged mice.

We examined the effect of two Japanese herbal medicines (Kampo-Hozai) on immunological functions and anti-tumor activity in old mice. Hochu-ekki-to (TJ-41) was remarkably effective in the restoration of impaired immune functions of old mice, in terms of number of T cells and NK cells, and anti-SRBC antibody response, while it was not effective in enhancing immune functions of young mice. Juzen-taiho-to was also effective in increasing the number of T cells, remarkably, and NK cells, slightly, in the aged mice. While a significant increase was not observed in young mice. NK activity increased both in young and old mice with the treatment of TJ-48. A significant decrease was observed in metastatic pulmonary colonies of B16 melanoma cells both in young and old mice treated with Juzen-taiho-to for 16 weeks. These results suggested that some of Japanese herbal medicines were useful in restoration of impaired immune functions of old mice and could be recommended for human elderly.