In vitro studies have allowed the discovery of Echinacea’s action mechanism: its polysaccharides and polyacetylenes fractions stimulate the phagocytosis of macrophages and the production of cytokines like interleukine-1, interleukine-6 (also called interferon beta), interleukine-10 and TNF alpha factor. This effect shows Echinacea’s ability to stimulate the immune system in cases of infection.(1)
Chicoric acid and analogues derived from caffeic acid are presently under investigation for their effect on HIV-1 replication.(2)
Echinacea, particularly the echinacosides and caffeic acid derivatives, might protect collagen structures against degradation (oxidation) caused by free radicals. This antioxidant effect is also useful to relieve the inflammation generated by the immune system during its fight against the viruses of colds.
Many clinical studies demonstrate Echinacea’s efficacy as an immune system stimulant.(3-5) According to the authors of an important meta-analysis (a review of articles on clinical studies), Echinacea is effective against respiratory infections, especially if taken as soon as the first symptoms appear.(6)
Echinaforce® specifically has also been the subject of conclusive clinical studies. A double-blind placebo-controlled study was conducted in Sweden on Echinaforce® tablets. 246 patients suffering from colds took either 6 Echinaforce® tablets daily, a special Echinacea preparation (7 times more concentrated), another form of Echinacea, or a placebo. Echinaforce® and the concentrated preparation were equally effective in reducing cold symptoms and significantly more effective than the other Echinacea preparation or the placebo.(7)
Another study conducted on 119 patients demonstrated a 60% improvement of cold symptoms with Echinaforce® tablets compared to a placebo.(8)
A recent study (April 2002) on 48 volunteers showed that Echinacea significantly increases one of the markers of immune system stimulation: properdine.(9)
According to a recent pilot study, an Echinacea extract seems to reduce the side effects of certain chemotherapy medications.(10)
References:
1-Burger Ra, Torres AR, Warren RP et al. Echinacea-induced cytokine by human macrophages. Int J Immunopharmacol 1997;19(7):371-9.
2-Lin Z, Neamati N, Zhao H et al. Chicoric acid analogues as HIV-1 integrase inhibitors. J Med Chem 1999;42(8):1401-14.
3-Gunning K. Echinacea in the treatment and prevention of upper respiratory tract infections. West J Med 1999;171:198-200.
4-Barrett B, Vohmann M, Calabrese C. Echinacea for upper respiratory infection. J Fam Pract 1999;48:628-35.
5-Grimm W, Muller HH. A randomized controlled trial of the effect of fluid extract of Echinacea purpurea on the incidence and severity of colds and respiratory infections. Am J Med 1999;106:138-43.
6-Barrett B, Vohmann M et Calabrese C. Echinacea for Upper respiratory infection. J Fam Pract 1999;48(8):628-35.
7-Brinkeborn RM, Shah DV, Degenring FH. Echinaforce® and other Echinacea fresh plant preparations in the treatment of the common cold. A randomized, placebo controlled, double-blind clinical trial. Phytomedicine 1999 Mar;6(1):1-6
8-Brinkeborn RM, Shah DV, Geissbühler S, Degenring FH. Echinaforce® dans le traitement des états grippaux aigus. Schweiz Zschr GanzheitsMedizin 1998;10(1):26-9.
9-Kim LS, Waters RF, Burkholder PM. Immunological activity of larch arabinogalactan and Echinacea: A preliminary, randomized, double-blind, placebo-controlled trial. Altern Med Rev 2002 Apr;7(2):138-149
10-Melchart D, Clemm C, Weber B et al. Polysaccharides isolated from Echinacea purpurea herba cell cultures to counteract undesired effects of chemotherapy--a pilot study. Phytother Res 2002 Mar;16(2):138-42
11-Gallo M, Sarkar M, Au W et al. Pregnancy outcome following gestational exposure to echinacea: a prospective controlled study. Arch Intern Med 2000;160(20):3141-3
