- Clinical data 90%
- Efficacy 80%
- Security 70%
- Toxicity 30%
Echinacea angustifolia D.C. var. angustifolia Brauneria angustifolia Heller, Echinacea pallida var. angustifolia (D.C.) Cronq. Echinacea pallida (Nutt.) Nutt. Echinacea angustifolia Hook, Rudbeckia pallida Nutt., Brauneria pallida Britt., Echinacea pallida f. albida Steyerm. E. angustifolia and E. pallida were regarded as varieties of the same species or even identical plants. However, in a revision of the genus Echinacea in 1968, McGregor classified them as two distinct species with E. angustifolia further divided into two varieties. A considerable amount of commercial “E. angustifolia” cultivated in Europe was, in fact, E. pallida. Data on E. angustifolia published prior to 1987 and based on material of commerce from Europe should be reviewed with caution. Current commercial preparations are derived primarily from E. angustifolia and E. pallida roots; the preparation of a monograph on E. purpurea root awaits further data. Asteraceae are also known as Compositae.
Echinacea angustifolia D.C. var. angustifolia Cylindrical or slightly tapering and sometimes spirally twisted, passing imperceptibly into a rhizome in the upper part; rhizome up to about 15mm in diameter, roots 4–10mm in diameter; outer surface pale brown to yellowish brown; rhizomes crowned with remains of the aerial stem and sometimes showing surface annulations; roots longitudinally wrinkled and deeply furrowed; fracture short when dry but becoming tough and pliable on exposure to air. Echinacea pallida (Nutt.) Nutt. Similar in appearance to E. angustifolia.
Major chemical constituents
A number of chemical entities have been identified and reported to be biologically active, including a volatile oil, alkamides, polyalkenes, polyalkynes, caffeic acid derivatives, and polysaccharides.
The volatile oil contains, among other compounds, pentadeca-(1,8-Z)- diene (44%), 1-pentadecene, ketoalkynes and ketoalkenes. More than 20 alkamides, mostly isobutylamides of C11–C16 straight-chain fatty acids with olefinic or acetylenic bonds, or both, are found in the roots; the highest concentration is in E. angustifolia, followed by E. purpurea, and the lowest is in E. pallida. The main alkamide is a mixture of isomeric dodeca-2,4,8,10-tetraenoic acid isobutylamides. Caffeic acid ester derivatives present include echinacoside, cynarin, and chicoric acid. Cynarin is present only in E. angustifolia, thus distinguishing it from the closely related E. pallida. Polysaccharide constituents are of two types: a heteroxylan of relative molecular mass about 35 000 and an arabinorhamnogalactan of relative molecular mass about 45 000. Other constituents include trace amounts of pyrrolizidine alkaloids (tussilagine (0.006%) and isotussilagine). At these concentrations, the alkaloidsare considered to be non-toxic, and since they lack the 1,2-unsaturated necine ring of alkaloids such as senecionine (structure in box) from Senecio
species, they are considered to have no hepatotoxic potential.
Uses supported by clinical data
Preparations of Radix Echinacea sp are administered orally in supportive therapy for colds and infections of the respiratory and urinary tract. Beneficial effects in the treatment of these infections are generally thought to be brought about by stimulation of the immune response.
Uses described in pharmacopoeias and in traditional systems of medicine
Uses described in folk medicine, not supported by experimental or clinical data
Treatment of yeast infections, side-effects of radiation therapy, rheumatoid arthritis, and food poisoning.
Current claims for the effectiveness of Radix Echinaceae as a stimulator of the immune system are based on over 350 scientific studies in the past 50 years. Numerous in vitro and in vivo studies have documented the activation of an immune response after treatment with Radix Echinaceae extracts. The immunostimulant effect is brought about by three mechanisms: activation of phagocytosis and stimulation of fibroblasts; increasing respiratory activity; and causing increased mobility of the leukocytes. Chemically standardized extracts, derived from roots and aerial parts from the three Echinacea species, have been assessed for their phagocytotic potential. All ethanolic root extracts increased phagocytosis in vitro. Inhibition of hyaluronidase activity, stimulation of the activity of the adrenal cortex, stimulation of the production of properdin (a serum protein which can neutralize bacteria and viruses), and stimulation of interferon production have also been reported after Echinacea treatments. The pharmacological activity of Echinacea sp. has been attributed to five component fractions in addition to the essential oil, namely the alkylamides, caffeic acid derivatives, polyalkynes, polyalkenes and polysaccharides. The lipophilic amides, alkamides and caffeic acid derivatives appear to contribute to the immunostimulant activity of the alcoholic Echinacea extracts by stimulating phagocytosis of polymorphonuclear neutrophil granulocytes. High molecular weight polysaccharides, including heteroxylan, which activates phagocytosis, and arabinogalactan, which promotes the release of tumour necrosis factor and the production of interleukin-1 and interferon beta, have also been implicated in the activity of the aqueous extracts and the powdered drug when taken orally. The overall immunostimulant activity of the alcoholic and aqueous Echinacea extracts appears to depend on the combined
effects of several constituents.
Echinacea extracts inhibit streptococcal and tissue hyaluronidase.
Inhibition of tissue and bacterial hyaluronidase is thought to localize the infection and prevent the spread of causative agents to other parts of the body. In addition to the direct antihyaluronidase activity, an indirect effect on the hyaluronic acid–hyaluronidase system has been reported. Stimulation of new tissue production by increasing the activity of fibroblasts, and stimulation of both blood- and tissue-produced phagocytosis, appear to be involved in this mechanism.
Echinacea extracts have anti-inflammatory activity.
An alkylamide fraction from Echinacea roots markedly inhibited activity in vitro in the 5-lipoxygenase model (porcine leukocytes). Topical application of a crude polysaccharide extract from E. angustifolia has been reported to reduce inflammation in the rat paw oedema model.
One placebo-controlled clinical study of 160 patients with infections of the upper respiratory tract has been performed. Significant improvement was observed after patients were treated with an aqueous-alcoholic tincture (1:5) at 90 drops/day (900 mg roots). The duration of the illness decreased from 13 to 9.8 days for bacterial infections, and from 12.9 to 9.1 days for viral infections.
External use Allergy to plants in the Asteraceae.
Internal use: Should not be used in serious conditions such as tuberculosis, leukosis, collagenosis, multiple sclerosis, AIDS, HIV infection and autoimmune disorders. Echinacea preparations should not be administered to people with a known allergy to any plant of the Asteraceae. Parenteral administration is rarely indicated owing to potential adverse side-effects (see Adverse reactions).
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