Immunopharmacological activity of Echinacea preparations following simulated digestion on murine macrophages and human peripheral blood mononuclear cells.

We have investigated the immunostimulatory, anti-inflammatory, and antioxidant activities of various Echinacea raw materials and commercially available products on murine macrophages and human peripheral blood mononuclear cells (PBMCs). To emulate oral dosing, a simulated digestion protocol was employed as a means of sample preparation. Echinacea-induced macrophage activation was used as a measure of immunostimulatory activity determined via quantitative assays for macrophage-derived factors including tumor necrosis factor alpha, interleukin (IL)-1alpha, IL-1beta, IL-6, IL-10, and nitric oxide. Echinacea herb and root powders were found to stimulate murine macrophage cytokine secretion as well as to significantly enhance the viability and/or proliferation of human PBMCs in vitro. In contrast, Echinacea extracts chemically standardized to phenolic acid or echinacoside content and fresh pressed juice preparations were found to be inactive as immunostimulatory agents but did display, to varying degrees, anti-inflammatory and antioxidant properties.