Synergistic effects of the alkaloid sinomenine in combination with the immunosuppressive drugs tacrolimus and mycophenolic acid.

The alkaloid sinomenine extracted from the medicinal plant Sinomenium acutum is used in China for the treatment of various rheumatic diseases. It has immunomodulatory properties in a cardiac allograft transplantation model. Its antiproliferative effect on human mononuclear cells in combination with different immunosuppressive drugs was further analysed in vitro. Sinomenine dose-dependently attenuated thymidine incorporation, interleukin-2 synthesis, and cell cycle progression of activated T-lymphocytes. Cell proliferation was synergistically decreased by addition of sinomenine together with suboptimal concentrations of the established immunosuppressive drugs tacrolimus or mycophenolic acid, respectively.