An evaluation of Echinacea angustifolia in experimental rhinovirus infections
ABSTRACT Echinacea has been widely used as an herbal remedy for the common cold, but efficacy studies have produced conflicting results, and there are a variety of echinacea products on the market with different phytochemical compositions. We evaluated the effect of chemically defined extracts from Echinacea angustifolia roots on rhinovirus infection.
Three preparations of echinacea, with distinct phytochemical profiles, were produced by extraction from E. angustifolia roots with supercritical carbon dioxide, 60 percent ethanol, or 20 percent ethanol. A total of 437 volunteers were randomly assigned to receive either prophylaxis (beginning seven days before the virus challenge) or treatment (beginning at the time of the challenge) either with one of these preparations or with placebo. The results for 399 volunteers who were challenged with rhinovirus type 39 and observed in a sequestered setting for five days were included in the data analysis.
There were no statistically significant effects of the three echinacea extracts on rates of infection or severity of symptoms. Similarly, there were no significant effects of treatment on the volume of nasal secretions, on polymorphonuclear leukocyte or interleukin-8 concentrations in nasal-lavage specimens, or on quantitative-virus titer.
The results of this study indicate that extracts of E. angustifolia root, either alone or in combination, do not have clinically significant effects on infection with a rhinovirus or on the clinical illness that results from it.
Full-textDOI: · Available from: Thomas C Hulsey, Jul 05, 2015
- SourceAvailable from: Scott Laster[Show abstract] [Hide abstract]
ABSTRACT: The goal of this study was to determine whether extracts and isolated alkylamides from Echinacea purpurea would be useful for prevention of the inflammatory response that accompanies infections with H1N1 influenza A. Seventeen extracts and 4 alkylamides were tested for the ability to inhibit production of cytokines, chemokines, and PGE₂ from RAW 264.7 macrophage-like cells infected with the H1N1 influenza A strain PR/8/34. The alkylamides undeca-2Z,4E-diene-8,10-diynic acid isobutylamide, dodeca-2E,4E,8Z,10E/Z-tetraenoic acid isobutylamide, dodeca-2E,4E-dienoic acid isobutylamide, and undeca-2E-ene-8,10-diynoic acid isobutylamide suppressed production of TNF-α and PGE₂ from infected cells. Dodeca-2E,4E-dienoic acid isobutylamide was especially effective at inhibiting production of these mediators and also strongly inhibited production of G-CSF, CCL2/MCP-1, CCL3/MIP-1α and CCL5/RANTES. In contrast, the ethanol extracts (75%), which were prepared from dormant roots of E. purpurea grown in different locations throughout North Carolina, displayed a range of effects from suppression to stimulation of mediator production. Precipitation of the extracts with ethanol removed the stimulatory activity, however, even after precipitation; many of the extracts did not display any suppressive activity. Analysis of the extracts revealed slight variations in concentration of alkylamides, caftaric acid, and cichoric acid, but the activity of the extracts did not strongly correlate with concentrations of these compounds. Our in vitro experiments suggest that E. purpurea extracts have the potential for use in alleviating the symptoms and pathology associated with infections with influenza A; however, further study will be necessary to define procedures necessary to unmask the alkylamide activity in crude extracts.International immunopharmacology 10/2010; 10(10):1268-78. DOI:10.1016/j.intimp.2010.07.009 · 2.71 Impact Factor
- [Show abstract] [Hide abstract]
ABSTRACT: Respiratory virus infections in hematopoietic cell transplant (HCT) recipients are a major cause of morbidity and mortality. While respiratory syncytial virus (RSV), human metapneumovirus, parainfluenzaviruses, and influenza viruses are well known for their potential to cause fatal pneumonia, information has only recently emerged regarding the significance of the newly discovered viruses, such as human coronaviruses NL63 and HKU1, and human bocavirus. Lymphopenia seems to be the most important risk factor for progression to lower respiratory tract disease. Airflow obstruction is another complication of respiratory virus infections after HCT, and data to date indicate this complication may occur following parainfluenza virus and RSV infection. Infection control procedures are key for prevention. Unfortunately, there are no randomized treatment studies, which make the interpretation of the literature on interventions difficult. This article reviews the spectrum of pathogens, epidemiology, risk factors and clinical manifestations of infection, as well as recent advances in diagnostic and clinical management.British Journal of Haematology 10/2008; 143(4):455-67. DOI:10.1111/j.1365-2141.2008.07295.x · 4.96 Impact Factor
- [Show abstract] [Hide abstract]
ABSTRACT: Echinacea (Asteraceae) extracts have been advocated tra-ditionally for use in individuals suffering from sore throats, coughs, and various other respiratory symptoms that could be due to bacterial infections. We therefore evaluated six different commercial Echinacea extracts, with defined com-position of standard marker compounds, for their ability to inactivate 15 different human pathogenic bacteria and two pathogenic fungi. The extracts were derived from E. angus-tifolia roots or mixtures of E. purpurea roots and aerial parts and contained different relative amounts of alkylamides and polysaccharides and similar overall concentrations of caffeic acid derivatives. Five bacteria, Streptococcus pyo-genes, Haemophilus influenzae, Legionella pneumophila, Clostridium difficile, and Propionibacterium acne, were very sensitive to one or more of the extracts, but the patterns of sensitivity were quite different for the various extracts. Furthermore, there were no correlations between bacterial sensitivity and the concentrations of marker compounds in the extracts. The other bacteria and fungi were either slightly sensitive to one or more extracts or were totally resistant. In conclusion, certain preparations of Echinacea, especially ethanol formulations, could provide useful pro-tection or symptom alleviation in cases of various upper and lower respiratory infections, such as sinusitis, bron-chitis, pharyngitis, tonsillitis, and pneumonia, as well as cutaneous infections, by means of their selective bacterici-dal activities, although we do not know which components of the extracts are responsible for these activities.Pharmaceutical Biology 01/2008; 46:111-116. DOI:10.1080/13880200701734919 · 1.34 Impact Factor