Herbal medicines for immunosuppression.

Herbal medicines have been used for centuries to treat different illnesses. Among more than 20,000 herbal medicines available for humans, a limited number have sufficiently been studied and numerous remained to be investigated for their efficacy in treating human diseases. A number of herbal products are in use for their immunosuppressive effects. This capacity of herbs may have useful applications in immune-mediated disorders including autoimmune diseases and organ transplant rejection. Plants such as Salvia miltiorrhiza and Tripterygium wilfordii has been shown to reduce inflammatory cytokines and mediators, indicating their value in the treatment of acute graft rejections and autoimmunity. Tanacetum parthenium inhibits the release of pro-inflammatory mediators from macrophages and lymphocytes and Curcuma longa down regulates the expression of cytokines and chemokines as well as the transcription factor NF-kappaB. There has been growing interest to investigate novel anti-inflammatory or immunosuppressive activities from various sources particularly herbal medicines. This review focuses on the plants that have recently received more attention regarding their influence on the immune system, being reported as immunosuppressive and anti-inflammatory agents and promising protective effects for immune-mediated diseases.