The Mechanism of Action of Ursolic Acid as a Potential Anti-Toxoplasmosis Agent, and Its Immunomodulatory Effects.

This study was performed to investigate the mechanism of action of ursolic acid in terms of anti- effects, including immunomodulatory effects. We evaluated the anti- effects of ursolic acid, and analyzed the production of nitric oxide (NO), reactive oxygen species (ROS), and cytokines through co-cultured immune cells, as well as the expression of intracellular organelles of . The subcellular organelles and granules of , particularly rhoptry protein 18, microneme protein 8, and inner membrane complex sub-compartment protein 3, were markedly decreased when was treated with ursolic acid, and their expressions were effectively inhibited. Furthermore, ursolic acid effectively increased the production of NO, ROS, interleukin (IL)-10, IL-12, granulocyte macrophage colony stimulating factor (GM-CSF), and interferon-β, while reducing the expression of IL-1β, IL-6, tumor necrosis factor alpha (TNF-α), and transforming growth factor beta 1 (TGF-β1) in -infected immune cells. These results demonstrate that ursolic acid not only causes anti- activity/action by effectively inhibiting the survival of and the subcellular organelles of , but also induces specific immunomodulatory effects in -infected immune cells. Therefore, this study indicates that ursolic acid can be effectively utilized as a potential candidate agent for developing novel anti-toxoplasmosis drugs, and has immunomodulatory activity.