Background Echinacea has been widely used as an herbal remedyfor the common cold, but efficacy studies have produced conflictingresults, and there are a variety of echinacea products on themarket with different phytochemical compositions. We evaluatedthe effect of chemically defined extracts from Echinacea angustifoliaroots on rhinovirus infection.
Methods Three preparations of echinacea, with distinct phytochemicalprofiles, were produced by extraction from E. angustifolia rootswith supercritical carbon dioxide, 60 percent ethanol, or 20percent ethanol. A total of 437 volunteers were randomly assignedto receive either prophylaxis (beginning seven days before thevirus challenge) or treatment (beginning at the time of thechallenge) either with one of these preparations or with placebo.The results for 399 volunteers who were challenged with rhinovirustype 39 and observed in a sequestered setting for five dayswere included in the data analysis.
Results There were no statistically significant effects of thethree echinacea extracts on rates of infection or severity ofsymptoms. Similarly, there were no significant effects of treatmenton the volume of nasal secretions, on polymorphonuclear leukocyteor interleukin-8 concentrations in nasal-lavage specimens, oron quantitative-virus titer.
Conclusions The results of this study indicate that extractsof E. angustifolia root, either alone or in combination, donot have clinically significant effects on infection with arhinovirus or on the clinical illness that results from it.
Source Information
From the University of Virginia School of Medicine, Charlottesville (R.B.T.); Karl-Franzens-Universitaet, Graz, Austria (R.B., K.W.); the Medical University of South Carolina, Charleston (T.C.H.); and Clemson University, Clemson, S.C. (J.D.G.).
Address reprint requests to Dr. Turner at the University of Virginia School of Medicine, P.O. Box 800386, Charlottesville, VA 22908, or at rbt2n{at}virginia.edu.
Turner, R. B.
(2009). Clinical Trials of Herbal Treatments. Eval Health Prof
32: 410-416
[Abstract]
Vohra, S., Johnston, B. C., Laycock, K. L., Midodzi, W. K., Dhunnoo, I., Harris, E., Baydala, L.
(2008). Safety and Tolerability of North American Ginseng Extract in the Treatment of Pediatric Upper Respiratory Tract Infection: A Phase II Randomized, Controlled Trial of 2 Dosing Schedules. Pediatrics
122: e402-e410
[Abstract][Full Text]
Davis, J. M., Murphy, E. A., McClellan, J. L., Carmichael, M. D., Gangemi, J. D.
(2008). Quercetin reduces susceptibility to influenza infection following stressful exercise. Am. J. Physiol. Regul. Integr. Comp. Physiol.
295: R505-R509
[Abstract][Full Text]
Flagel, L. E., Rapp, R. A., Grover, C. E., Widrlechner, M. P., Hawkins, J., Grafenberg, J. L., Alvarez, I., Chung, G. Y., Wendel, J. F.
(2008). Phylogenetic, morphological, and chemotaxonomic incongruence in the North American endemic genus Echinacea. Am. J. Bot.
95: 756-765
[Abstract][Full Text]
Nichols, W. G., Peck Campbell, A. J., Boeckh, M.
(2008). Respiratory Viruses Other than Influenza Virus: Impact and Therapeutic Advances. Clin. Microbiol. Rev.
21: 274-290
[Abstract][Full Text]
Birt, D. F, Widrlechner, M. P, LaLone, C. A, Wu, L., Bae, J., Solco, A. K., Kraus, G. A, Murphy, P. A, Wurtele, E. S, Leng, Q., Hebert, S. C, Maury, W. J, Price, J. P
(2008). Echinacea in infection. Am. J. Clin. Nutr.
87: 488S-492S
[Abstract][Full Text]
Bardia, A., Nisly, N. L., Zimmerman, M. B., Gryzlak, B. M., Wallace, R. B.
(2007). Use of Herbs Among Adults Based on Evidence-Based Indications: Findings From the National Health Interview Survey. Mayo Clin Proc.
82: 561-566
[Abstract][Full Text]
Charrois, T. L., Hrudey, J., Vohra, S.
(2006). Echinacea. Pediatr. Rev.
27: 385-387
[Full Text]
Barrett, B., Brown, R., Voland, R., Maberry, R., Turner, R.
(2006). Relations among questionnaire and laboratory measures of rhinovirus infection. Eur Respir J
28: 358-361
[Abstract][Full Text]
Raduner, S., Majewska, A., Chen, J.-Z., Xie, X.-Q., Hamon, J., Faller, B., Altmann, K.-H., Gertsch, J.
(2006). Alkylamides from Echinacea Are a New Class of Cannabinomimetics: CANNABINOID TYPE 2 RECEPTOR-DEPENDENT AND -INDEPENDENT IMMUNOMODULATORY EFFECTS. J. Biol. Chem.
281: 14192-14206
[Abstract][Full Text]
Leach, M., Farnsworth, N. R., Leach, M., Turner, R. B., Gangemi, J. D.
(2005). Echinacea angustifolia in rhinovirus infections.. NEJM
353: 1971-1972
[Full Text]
(2005). Echinacea Not Effective for the Common Cold. Journal Watch Dermatology
2005: 7-7
[Full Text]