Differences Among Species of Echinacea
Echinacea is a very popular herb used in supportive therapy for influenza and colds, but there are several species used in the remedies lining store shelves. How are they different? Which should I use? Is there one that is “best” or “strongest”? Problems of botanical identity and commercial adulteration have led to confusion in research and study; and these questions remain, for the most part, unanswered. As part of the herbal medicine course I am taking, I did some research on the subject. Disclaimer: This is a summary of personal research, shared here for educational purposes and not intended to diagnose or treat any illness.
Although the chemical composition clearly differs among species of Echinacea, differences in their immunomodulatory effects remain unclear. [1] A 2001 study compared the immunomodulatory effects of seven different Echinacea species, extracted by ethanol decoction and water infusion. The researchers suggested that E. augustifolia and E. simulata enhanced the immune system, while E. pallida and E. sanguinea acted as immunosuppressants. [2] A 2006 study comparing E. purpurea, E. angustifolia and E. pallida states in the abstract that all three of the species were found to have antioxidant properties. [3]
E. pallida root and E. purpurea herb have both been extensively studied and are approved by the German Commission E Monographs for therapeutic use. [4] The first is generally used in supportive therapy for influenza-like infection. The second is generally used in supportive therapy for colds and chronic infections of the respiratory tract and lower urinary tracts, as well as externally for the treatment of poorly-healing wounds and chronic ulcerations. [5]
The German Commission E Monographs have not approved the use of E. augustifolia herb and root, or E. pallida herb, [6] due to a lack of “current pharmacological and clinical studies.” [7] That is, they do not have the same scientific validation—though traditional use does suggest effectiveness.
Sources:
[1] "A comparison of immunomodulatory properties across Echinacea species has yet to be conducted; thus, it is unclear at present how Echinacea species compare to one another regarding potential immunomodulatory characteristics." “Phenetic comparison of seven Echinacea Species based on immunomodulatory characteristics.” [Econ Bot. 2006] <http://www.ncbi.nlm.nih.gov/pubmed/18301733>
[1] "...it can be seen from Table 2 that Echinacea pallida tends to exhibit no or suppressive immune modulation, whereas E. angustifolia tends to exhibit mostly enhancing effects on immune function. Our dendrogram suggests that E. angustifolia and E. pallida have very different immunomodulatory capabilities from one another. It also suggests that if an immunosuppressive effect is desirable, species such as E. pallida and E. sanguinea should be favored; likewise, if enhanced immune responses are desired, species such as E. angustifolia and E. simulata should be selected. It is important to stress that these data are based on the testing of only ethanol decoctions and water infusions from a representative sampling of species and accessions; the interpretation is thus limited to these extract types. Different immunomodulatory properties may be obtained by different extraction methods from different accessions." “Phenetic comparison of seven Echinacea Species based on immunomodulatory characteristics.” [Econ Bot. 2006] <http://www.ncbi.nlm.nih.gov/pubmed/18301733>
[3] "Extracts of the roots and leaves of all three species were found to have antioxidant properties in a free radical scavenging assay and in a lipid peroxidation assay."“Comparison of chemical components and antioxidant capacity of different Echinacea species.” [J Pharmacol. 2001] <http://www.ncbi.nlm.nih.gov/pubmed/11428661>
[4] “Of the four Echinacea monographs, two are positive (Echinacea pallida root and E. purpurea leaf)....” The German E Commission Monographs <http://books.google.com/books?id=Q8YOxB6jXsIC&dq=german+commission+e+monograph+echinacea&q=echinacea#v=snippet&q=echinacea&f=false>
[5] Shonda Parker <http://www.naturallyhealthy.org/askshonda3.php>
[6] “Of the four Echinacea monographs,.... two are negative (Echinacea purpurea root and E. augustifolia root)....” The German E Commission Monographs <http://books.google.com/books?id=Q8YOxB6jXsIC&dq=german+commission+e+monograph+echinacea&q=echinacea#v=snippet&q=echinacea&f=false>
[7] “Therefore, lack of current pharmacological and clinical studies on E. augustifolia root and E. augustifolia/ E. pallida aerial (above-ground) parts resulted in the issuance of a negative monograph until further scientific information become available (Foster, 1996).” Ibid.
Friday, February 10, 2012