Immunomodulatory Activity of Astragalus, Ginseng and Echinacea: From Keith Block and Mark Mead to Today, Have We Moved On?

Herbal products have a long history of general usage in traditional Chinese and other complementary medicine protocols. They are used in the treatment of a variety of conditions most importantly stimulation or inhibition of the immune system. In this regard, of particular importance are Astragalus membranaceous, Panax ginseng and Echinacea purpurea; the latter two having found favor across the globe and in common usage by millions of individuals hoping to improve cancer symptoms (P. ginseng) and fight colds and influenza (E. purpurea). Hundreds of papers have been written about these three phytochemicals, but the most rigorous and widely cited was written by Block and Mead in 2003, who underlined the weaknesses in the scientific rigor associated with evaluating these medicines as well as suggesting strategies to move forward. Using Block and Mead as a platform, this review aims to evaluate whether our knowledge base has improved subsequently.