From Echinacea species

Huntley AL, Thompson Coon J, Ernst E. The safety of herbal medicinal products derived from Echinacea species a systematic review. Drug Saf. 2005 28 387-400. 

Cheminat, A., Zawatzky, R., Becher, H., and Brouillard, R. 1988. Caffeoyl conjugates from Echinacea species structures and biological activity. Phytochemistry 27, 2787-2794. 

Jager, H., Meinel, L., Dietz, B., Lapke, C., Bauer, R., Merkle, H., and Heilmann, L. 2002. Transport of alkamides from Echinacea species through Caco-2 monolayers. Planta Med. 68, 469-471. 

Muller-Jakic, B. et al., In vitro inhibition of cyclooxygenase and 5-lipoxygenase by alka-mides from Echinacea and Achillea species, Planta Med, 60, 37, 1994. 

Echinacea Echinacea species (E angustifolia E pallida purpurea) Roots and seeds from the echinacea plant Immune stimulant treatment of colds and upper respiratory tract infections applied topically to promote wound healing... 

Gas chromatography (GC)-MS coupled with multivariate statistical analysis proved valuable in verifying the authenticity of Echinacea species (Lienert et al, 1998). Similar root extracts could be grouped, based on the identified compounds from the GC-run, by principal component and cluster analysis. The correct grouping of the Echinacea species (i.e., purpurea, angustifolia, and pallida) was not influenced by the extraction method or by the aging process of the roots. 

Polyunsaturated alkamides have been isolated from Aaronsohnia, Achillea, Anacyclus, and Echinacea species. Due to the structural similarity of alkamides to arachidonic acid, it is likely that alkamides act as competitive inhibitors of COX and LOX enzymes. At a concentration of 50 pg/ml, all twenty tested alkamides from Achillea and Echinacea species showed 21-... 

Denotes the percentage of volatile in the Echinacea species. Data taken from Mazza and Cotrell, 1999. 

In an in vitro study involving alkamides from Echinacea angustifolia and several Achillea species, 20 compounds tested were relatively potent inhibitors of cyclooxygenase, while a few also inhibited 5-lipoxygenase (Muller-Jakic et al. 1994). The two enzymes are involved in the metabolism of arachidonic acid, the major pathway to inflammation. Considering the structural similarities to arachidonic acid, the authors propose the alkamides act as analogues, competitively inhibiting the enzymes. 

Antioxidant activity. Caffeoyl derivatives from echinacea, for example, echinacoside and cynarine, are capable of reducing collagen damage produced by reactive oxygen species and/or other radicals (IC50 15-90 pM). " ... 

The three most widely used species of Echinacea are Echinacea purpurea, E pallida, and E angustifolia. The chemical constituents include flavonoids, lipophilic constituents (eg, alkamides, polyacetylenes), water-soluble polysaccharides, and water-soluble caffeoyl conjugates (eg, echinacoside, chicoric acid, caffeic acid). Within any marketed echinacea formulation, the relative amounts of these components are dependent upon the species used, the method of manufacture, and the plant parts used. Epurpurea has been the most widely studied in clinical trials. Although the active constituents of echinacea are not completely known, chicoric acid from E purpurea and echinacoside from E pallida and E angustifolia, as well as alkamides and polysaccharides, are most often noted as having immune-modulating properties. Most commercial formulations, however, are not standardized for any particular constituent. 

So does echinacea work One would think that this would be a relatively simple question to answer, but it isn t. The best reply I can come up with is that some echinacea preparations work for some conditions in some people some of the time. I realize that this is not very satisfying, but such is the nature of the herbal beast. First of all there are nine species of echinacea, although manufacturers only use three (E. purpurea, E. angustifolia, and E. pallida) to make supplements. Each of these plants has a different chemical profile. Each contains dozens of compounds some they have in common, some they don t. Furthermore, their leaves, flowers, stems, and roots have different compositions. An alcohol extract of the root will have a very different chemical makeup from a hexane extract of the stem or from capsules filled with dried, powdered leaves. Before we even... 

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