There are at least 9 species of echinacea. The ones most commonly studied are E. purpura, E. palida, and E. angustifolia.
Echinacea is native to Kansas, Nebraska, and Missouri. There has been confusion regarding the identification of echinacea. Because of this confusion, it should be recog?nized that much of the early research conducted on this plant (in particular with European E. angustifolia) was probably conducted on E. pallida. At least 6 synonyms have been documented for these plants.
E. angustifolia is a perennial herb with narrow leaves and a stout stem that grows to 90 cm in height. The plant terminates in a single, colorful flower head. The plant imparts a pungent, acrid taste when chewed and causes tingling of the lips and tongue.
Echinacea products have been found to be adulterated with another member of the family Compositae, Parthe?nium integrifolium L. This plant has no pharmacologic activity.
Echinacea is a popular herbal remedy in the central US, an area to which it is indigenous. The plant was used in traditional medicine by the American Indians and quickly adopted by the settlers. During the 1800s, claims for the curative properties of the plant ranged from a blood purifier to a treatment for dizziness and rattle?snake bites. During the early part of the 20th century, extracts of the plant were used as anti-infectives; how?ever, the use of these products fell out of favor after the discovery of modern antibiotics.
The plant and its extracts continue to be used topically for wound-healing action and internally to stimulate the im?mune system. Most of the research during the past 10 years has focused on the immunostimulant properties of this plant.
Echinacea contains about 0.1 % echinaco?side, a caffeic acid glycoside. The pungent component of the plant is echinacein, a isobutylamide. This compound is toxic to adult houseflies. The plant also contains a complex mixture of components that are now elucidated. Depending on the species, the essenua obtained from the root may be high in unsaturated a ketones or isobutylamides. Fresh aerial portio echinacea contain a highly volatile germacrene aiel that is not usually identified in dried plant material addition, a number of alkamides have been found in. lipophilic fraction of E. angustifolia and E. purproots.
A small but growing body 01 dence is developing to support the traditional use echinacea as a wound-healing agent and immunos' lant. Most studies have indicated that the lipophilic fracti the root and leaves contains the most potent imm. stimulating components. Although a number of phaco logically active components have been isolated single compound appears to be responsible for the activity. Polyunsaturated alkamides from E. ~ have been shown to inhibit in vitro the activity of sl cyclooxygenase and porcine 5-lipoxygenase
Treatment of the common cold: Nineteen Gen controlled clinical trials examined the efficacy of entechinacea preparations, alone or in combinatiothe prevention or treatment of upper respirato infections (URis) including the common cold. Thea rated the overall quality of the studies, with a 1M score of 37% and a range of 7% to 70%.8 These re correspond to the average scores (38.5%) foundfor( clinical trials in journals from 1990.9 The authors review determined that the studies available as 011 revealed that echinacea may have an effect on, immune system, but that there is insufficient evide provide specific recommendations.M treatment, not for the prevention of URis, butthereM a lack of definitive information to provide specific