Roter Sonnenhut (Echinacea purpurea L.)
? During the 1918 flu pandemic many of the naturopathic doctors in North America used Echinacea as one of their most important herbal drugs [1]. Except for the empiric evidence of the pronounced therapeutic Echinacea effects a rationale for its effectiveness in acute upper respiratory infections (ARI), influenza like illnesses (ILI) or influenza itself was missing for decades. Have there been any problems with the “classical theory” of the assumed “stimulation of the immune system” by Echinacea extracts?
! Our understanding of the immune system has changed radically in recent years. We now view the immune system as a network composed of stimulatory and inhibitory responses which is normally balanced in a healthy person. However, in response to a virus or bacterial infection, we often produce an exaggerated innate immune response, which results in a so-called proinflammatory response, with resulting secretion of cytokines and other inflammatory mediators. These mediators are in fact responsible for many of the classical symptoms of “colds and flu”. These responses occur within a day of the infection, long before the adaptive immune response, which is responsible for antibody formation. One of the most important effects of Echinacea, as demonstrated in laboratory experiments with Echinaforce®, is the reversal of this proinflammatory response. In other words the Echinacea can act as an antiinflammatory agent and hence restore the balance in the immune system.
The concept of immune stimulation by Echinacea includes mainly the proliferation of several immune cells and the increase of certain immune functions in vitro and in vivo. Since these effects are time dependent, they only partially explain the instantaneous therapeutic effectivity in acute infections. Or in essence: The former concept of the Echinacea induced immune stimulation was an example of the “black and white thinking” during the antibiotic era in medicine. The “bad” players were bacteria and viruses, the “good” – of course – were immune cells and their activities. Yet nowadays in microbiology it has become clear that this concept is much too simple to fit into reality.
? One of your new insights in Echinacea’s mode of action – the modulation of cytokines – means a paradigmatic shift also for the herbal medicine. What is the news from your laboratory?
! We now recognize a range of diseases in which certain functions of the immune system are exaggerated – allergy and atopy, autoimmune, autoaggressive diseases, sepsis and the lethal effects of avian influenza infections in healthy people. One of the pathogenic effects in infectious diseases is a dysfunctional over-production and ‑secretion of proinflammatory cytokines and chemokines by infected cells (“cytokine storm”). Such a “hypercytokinemia” is the main reason for many of the typical symptoms during an ARI. Such a response can be elicited even for viruses with relatively low pathogenic potential, such as rhinoviruses, which are responsible for many common colds. In summary: The Echinacea extract Echinaforce® modulates and normalizes the cellular hypersecretion of cytokines during a virus infection in vitro [2, 3, 4]. This explains why Echinacea in symptomatic ARI has an immediate therapeutic effect even though the above mentioned immune stimulation is only just starting.
? You and your team also could show a direct antiviral effect of the herbal extract Echinaforce®?
! Yes, the Swiss product exhibits a very pronounced antiviral effect in vitro – this means a complete block of the viral replication in infected cells (especially pronounced for influenza virus, respiratory syncytial virus and herpes simplex virus)
? Are there new insights of the molecular basis of the antiviral and immunmodulatory effects of Echinaforce®?
! Herbal extracts often contain a mixture of hundreds of different natural substances. So we cannot yet explain the mode of action of Echinacea. Evidence to date suggests that Echinacea blocks the binding of influenza virus to cellular receptors, effectively preventing replication and spread of the virus. We also showed in earlier studies that Echinacea can interact with intracellular transcription factors that promote the production and secretion of cytokines.
? Even if these results are purely experimental, what is your clinical extrapolation to a rational use in case of ARI, ILI or influenza? Do you have any recommendation for the daily clinical practice?
! Yes, our scientific results originate mainly from our laboratory work. However we have just completed analogous studies on virus infected organotypic models (3D tissues) of human airway tissues, and the results support the previous studies done with 2D monolayer cultures of bronchial cells. In addition we showed that the Echinacea did not adversely affect tissue structure or the cilia on epithelial cells, and furthermore the virus-induced secretion of mucus in these tissues was completely reversed by Echinaforce®. Therefore it is reasonable to promote the traditional uses of Echinacea in infectious diseases as described by the eclectic herbal doctors and the North American Indians. Our results give insights in the pharmacogenetics of Echinacea, especially of the activity of very low doses and the multiple modes of action. As the term complementary medicine indicates, the use of Echinacea should complement all other necessary therapeutic measures. Therefore I recommend Echinaforce as useful and valuable add-on in case of a multimodal therapy. Of course there are also many cases of less aggressive respiratory infections or common colds where the extract is useful for monotherapy.
? Would you use Echinaforce in swine flu by yourself? If yes, what are your recommendations for an optimal usage?
! In consideration of the multiple beneficial activities of Echinaforce just described, I would definitely advocate consumption of Echinaforce in the recommended dosage. I would have no hesitation in taking it myself. Furthermore I recommend! use of Echinaforce in the context of other important – naturopathic – measures. E. g. reduction of stress, both mentally and physically, stopping intensive exercise and sporting activities, adequate bed rest, enough sleep, plenty of fluids and abandonment of therapies with exhausting side-effects.
?! Prof. Hudson, many thanks for your valuable information!
* the Echinacea herbal extract tested is equivalent, in terms of raw-material use, manufacturing and composition, to the product Echinaforce® (A. Vogel Bioforce AG, Roggwil, Switzerland).
Note: Professor Jim Hudson is considered to be one of the foremost virologists in Western Canada and is currently Professor Emeritus at The University of British Columbia. He has published over 130 papers in peer-reviewed journals and written a number of books, including “Antiviral Compounds from Plants”. His research interests include elucidating the molecular mechanisms of action of herbal medicines and several collaborative projects with Institutes in developing countries in Africa and Asia.
Rainer H. Bubenzer, the interviewer, is a senior health consultant, experienced medical author, specialist in complementary medicine for many years and editor in chief of heilpflanzen-welt.de.
Autor
Rainer H. Bubenzer, Berlin, 2009.
Quellen
Lloyd JU et al.: Favorite Remedies Used in Treatment of Influenza. Lloyd Bros Inc., Cincinnati, Feb 1919. In: Abascal K, Yarnell E: Herbal Treatments for Pandemic Influenza: Learning from the Eclectics’ Experience. Alternative and Complementary Therapies. 2006 Oct;12(5): 214221.
Sharma M, Arnason JT, Burt A, Hudson JB: Echinacea extracts modulate the pattern of chemokine and cytokine secretion in rhinovirusinfected and uninfected epithelial cells. Phytother Res. 2006 Feb;20(2):14752 (Abstract).
Sharma M, Schoop R, Hudson JB: Echinacea as an antiinflammatory agent: the influence of physiologically relevant parameters. Phytother Res. 2009 Jun;23(6):8637 (Abstract).
Sharma M, Anderson SA, Schoop R, Hudson JB: Induction of multiple proinflammatory cytokines by respiratory viruses and reversal by standardized Echinacea, a potent antiviral herbal extract. Antiviral Res. 2009 Aug;83(2):16570 (Abstract).
Sharma M, Arnason JT, Hudson JB: Echinacea extracts modulate the production of multiple transcription factors in uninfected cells and rhinovirus-infected cells. Phytother Res. 2006 Dec;20(12):10749 (Abstract).