Cichoric Acid and Isobutylamide Content in Echinacea purpurea as Influenced by Flower Developmental Stages

Echinacea purpurea (L.) Moench, Asteraceae, a native of North America is among the most frequently utilized Echinacea spp. for medicinal, cosmetic, and beverage preparations. Most of the echinacea preparations in the industry originate from wild harvesting and few from non-standardized (unregulated) cultivation and harvesting. According to the recent reports (Brevoort 1996), echinacea preparations are among the best selling herbal immunostimulant products in health food stores in the US. Currently more than 800 echinaceacontaining drugs, including homeopathic preparations, are available on the German market. Most of the products are derived either from the aerial or underground parts of Echinacea. Within several herbs, Echinacea species are among the main investigation targets, because of their value as immunostimulants (Bauer and Wagner 1991). The therapeutic effect of Echinacea has been assigned to the presence of caffeic acid derivatives such as cichoric acid, echinacoside, chlorogenic acid (Fig. 1), and lipophilic polyacetylene-derived compounds, such as alkylamides, constituting isobutylamides (Fig. 2), and various other components found in the hydroalcoholic extracts. The low molecular weight constituents of hydroalcoholic tinctures can be determined by HPLC or TLC analysis. Cichoric acid has been shown to possess phagocytosis stimulatory activity in vitro and in vivo, while echinacoside has antibacterial and antiviral activity (Bauer and Wagner 1991). Cichoric acid was also recently been shown to inhibit hyaluronidase and to protect collagen type III from free radical induced degradation, while lipophilic alkamide (isobutylamides), polyacetylenes, and glycoproteins/polysaccharides have been shown to possess immunomodulatory activity (Bauer and Wagner 1991). When testing the alcoholic extracts obtained from the aerial parts and from the roots for phagocytosis stimulating activity, the lipophilic fraction alkamide (isobutylamides) showed the highest activity (Bauer and Wagner 1991). Most of the alkamides are reported to be responsible potent inhibitors of cyclooxygenase, while the requirement for inhibition of 5lipoxigenase depends more on the particular structure of the single compound. The inhibitory properties of the alkamides on arachidonic acid metabolism are in accordance with the traditional use of the herbal drugs in the therapy of inflammatory diseases. Alkamide (isobutylamides) is also responsible for local tongue anaesthesis (tingling effect) when ingested and used as an informal test for the quality of Echinacea (Bauer and Wagner 1991). Purified alkamide fractions (isobutylamides) from E. purpurea and E. angustifolia were recently shown to enhance phagocytosis in the Carbon-Clearance-Test by a factor of 1.5 to 1.7 thereby contributing to the immunstimulatory activity of echinacea tinctures (Bauer and Wagner 1991). It is possible, therefore, to consider that cichoric acid, echinacoside, and alkamide (isobutylamides) are parts of the active principles and suitable for standardization of E. purpurea row material and finished products. There is no published scientific information to date on the relationship between flower developmental stages and the accumulation of some of the above mentioned components of E. purpurea. Recent phytochemical investigation shows that there is a tremendous variation in the quality of echinacea products that were made available from various international sources (Letchamo et al. 1999). Furthermore, there is a dire need for genetic improvement and precise knowledge on the influence of ecological and develCichoric acid