By Heidi Li, NOW Methods Department [former]
Echinacea herbal medicines are traditionally used for treatment of inflammatory and viral diseases such as cold, cough and upper respiratory infections. Recent studies show that they can also be used as antioxidants or free radical terminators to prevent cardiovascular disease, arthritis and aging. In fact, Echinacea has become one of the most widely used herbal medicines and dietary supplements in Europe, North America, and Australia.
The parts of Echinacea used in herbal medicines are the roots and aerial parts of three species: Echinacea purpurea, Echinacea. angustifolia and Echinacea pallida. The main active compounds of Echinacea are caffeic acid derivatives (phenolic compounds), alkamides and polysaccharides. Among caffeic acid derivatives, several components, such as caftaric acid, chlorogenic acid, caffeic acid, echinacoside and chichoric acid, are identified from Echinacea extracts. Chicoric acid is the major phenolic compound in E. purpurea, but minor in E. angustifolia and E. pallida. Echinacoside is the main phenolic compound in E. angustifolia and E. pallida, but only trace is found in E. purpurea.
Studies have shown that chichoric acid has immunostimulating effects, as well as antioxidant properties. Recently, it has been found to inhibit HIV-1 replication. Echinacoside does not contribute its immunostimulating activity, but it has antioxidant and cicatrizing activities.
The pharmacological activity of each Echinacea species appears to reflect the slight variation in the amount of active ingredients and their chemical profiles. All three species of Echinacea are found to have a protective effect on the free radical-induced degradation of collagen, which is probably due to its polyphenolic compounds. Extracts of E. purpurea roots have greater free radical scavenging capacity than those of E. pallida or E. angustifolia due to more amounts of phenolics constitute found in E. purpurea. E. purpurea is also well known to boost the immune system in prevention of common cold, flu and chronic respiratory infections because it is rich in cichoric acid.
Nutraceutical preparations of Echinacea are primarily based on the extracts or juices from their roots, leaves, stems and flowers. In herbals and supplements of Echinacea, the active ingredients in recommended therapeutic amounts depend upon the quality of plant material, preparation procedures, formulations and storage conditions. These active ingredients, especially phenolic acids, are mainly responsible for the pharmacological activities of Echinacea extracts and plant materials. Therefore, the profile of their content represents a useful fingerprint to define the identity and the quality of these products.
To ensure the quality of products, it is important to have reliable and practical analytical methods for the determination of phenolic acids in complex natural matrices. It is also a necessary step to clearly identify the different species of Echinacea to distinguish the efficacy of the different plants and their parts for a proper therapeutic usage.
Phenolic compounds of Echinacea have been studied with several analytical techniques, such as HPTLC, UV and HPLC. To standardize Echinacea products, NOW has developed HPLC method based on official U. S. Pharmacopeia method. This method validates the analytical procedures used for the determination of total phenolics in Echinacea products. This analytical method is accurate, efficient and simultaneously determines typical levels of various phenolic compounds, ensuring the quality of NOW Echinacea products.