The American coneflower: a prophylactic role involving nonspecific immunity

In humans, considerable circumstantial evidence exists that indicates soluble root extracts of the American coneflower, genus Echinacea, may act to ameliorate virus-mediated afflictions, such as the common cold, influenza, and even AIDS and virus-based tumors. This study was designed to quantify, in normal mice, Echinacea-mediated, quantitative, dynamic changes, with time on both mature and precursor cells, of all the hemopoietic and immune-cell lineages in the spleen and bone marrow.

A specific, commercially prepared potent extract of Echinacea root was provided daily in the diet for either 1 week or 2 weeks with the aim of establishing a possible mechanism of action for this herb.

The data revealed that natural-killer (NK) cells and monocytes, both mediators of nonspecific immunity and well-demonstrated killers of virus-containing cells, were numerically and significantly increased in both the bone marrow and the spleen as early as 1 week after beginning treatment with the dietary herb. In contrast to our observations with NK cells and monocytes, the sizes of all other hemopoietic and immune cell populations in these two organs remained at control levels even after 2 weeks of daily dietary Echinacea.

The work has demonstrated the specific nature of Echinacea-derived phytochemicals in acting as stimulants of those cells responsible for nonspecific immunity, as the first line of defense against virus-infected/transformed cells. The observations that these cells were elevated in the bone marrow indicates that at least one mechanism of action of this herb, is to stimulate new cell production in situ. The significant elevation of these two fundamental immune-cell populations, in normal animals, suggests a prophylactic role for this herb.