In 2006, Oregon’s Wild Harvest participated in a study; The Effect of Echinacea purpurea, Astragalus membranaceus, and Glycyrrhiza glabra on Immune Cell Activation and Proliferation in Humans. It involved 16 healthy subjects in a double-blind, placebo controlled randomized clinical trial. The subjects were randomized to solutions of Echinacea only, Astragalus only, Glycyrrhiza only, the combination of all three in equal parts, and placebo. The subjects received 7.5 ml does twice a day for seven days. Peripheral blood was drawn from the subjects three times before ingesting the herbal solution, after 24 hours, and seven days after herbal ingestion. White blood cells were separated from whole blood and analyzed to determine immune activation through the cell surface protein CD69. Immune regulation was determined by CD25 expression on CD4 T cells.
Researchers found that:
- Echinacea and Glycyrrhiza were able to stimulate proliferation of CD4 T cells, CD8 T cells and NK cells when administered orally to the study subjects.
- All three herbs – administered either singly or in combination – were able to activity CD8 T cells. Astragalus caused the most activation.
- Glycyrrhiza was able to stimulate NK activation.
- All the subjects who received Echinacea tincture showed CD25 activation at 24 hours compared to 0 hours, which persisted at seven days.
- Of great interest to the researchers was the simultaneous expression of activation (CD69) and regulation (CD25), present in the same patients.
The results demonstrate that Echinacea, Astragalus, and Glycyrrhiza herbal tinctures stimulate CD4 T cells. Thus, the authors believe that these herbs do work in enhancing the immune system, but are likely to be most effective when the essential medical qualities are applied in a certain application. The team also stated that this study, supported by naturopathic and medical communities, demonstrates that further collaborative research on the use of herbs in enhancing the body’s immune system is warranted.