Immune modulation of macrophage pro-inflammatory response by goldenseal and Astragalus extracts

Goldenseal (Hydrastis canadenisis) is a native American medicinal plant used as an immune stimulant. Astragalus (Astragalus membranaceus) is a widely used herbal product in China, other Asian countries, and the United States as an immune stimulant to be taken on first clinical signs of infection. In this study, the innate effects of goldenseal and Astragalus on pro-inflammatory cytokines produced by cultured macrophages were examined using two different commercial preparations of goldenseal and Astragalus. Both goldenseal and Astragalus were found to exhibit little to no direct effect on stimulation of mouse macrophages (J774A.1 cells), with only Astragalus able to affect production of tumor necrosis factor (TNF)-alpha when used in high concentrations. However, both goldenseal and Astragalus were able to modify responses from lipopolysaccharide-stimulated macrophages, with identified immunomodulatory effects to reduce production of TNF-alpha, interleukin (IL)-6, IL-10, and IL-12 in a dose-dependent manner. The results obtained indicate that both goldenseal and Astragalus exhibit abilities to modulate macrophage responses during stimulation. Therefore, it is hypothesized that their historical use as therapeutic agents may be due to reduction in the pro-inflammatory response that indirectly leads to limiting of clinical symptoms during infection. Both products differ in their immune stimulatory patterns, offering insight into differential use and therapeutic potential of these products to regulate macrophage immune responses and activation events.