Sari, A.O., M.R. Morales, and J.E. Simon. 1999. Echinacea angustifolia: An Emerging Medicinal. p. 490493. In: J. Janick (ed.), Perspectives on new crops and new uses. ASHS Press, Alexandria, VA.
The genus Echinacea (Asteraceae) is native to North America and consists of nine species (McGregor 1968). E. angustifolia DC, a narrow leafed species, is distributed on barrens and dry prairies from Minnesota to Texas, Oklahoma, Kansas, Nebraska, Iowa, the Dakotas, Colorado, Wyoming, Montana, Saskatchewan, and Manitoba (McGregor 1968; Kindscher 1989; Foster 1991). E. angustifolia grows lower and exhibits a smaller leaf area and biomass than E. pallida (Nutt.) Nutt. and E. purpurea (L.) Moench. Echinacea angustifolia grows up to 60 cm and usually branches simple not sparsely. The ligules of E. angustifolia are also short (to 5 cm) and the pollen is yellow (Hobbs 1989). E. purpurea grows taller (to 150 cm), branches more, and its pollen is also yellow. E. purpurea has wider leaves than E. angustifolia and E. pallida. Echinacea pallida is also simple branched like E. angustifolia, but grows taller (to 90 cm) than E. angustifolia, and has white pollen (Hobbs 1989). As a result of the slower growth, E. angustifolia is a weaker competitor to weeds than E. pallida (Snyder et al. 1994). The ray flowers surrounding each Echinacea flower head are sterile (Hobbs 1989; Foster 1991; Feghahati 1994).
Three Echinacea species (E. purpurea, E. angustifolia, and E. pallida) have medical properties (Schulthess et al. 1991), and are commercially traded as medicinal plants. Native Americans used echinacea extensively for the treatment of snake and other venomous bites, rabies, toothaches, coughs, soremouth, throat, dyspepsia, colds, colic, headache, and stomach cramps (Hobbs 1989; Kindscher 1989; Foster 1991). European settlers first used echinacea around the beginning of 19th century. By 1921, echinacea preparations were among the most widely sold medicines extracted from an American plant (Flannery 1998). Echinacea appears to have strong anti-inflammatory activity, wound-healing action, stimulates the immune system, and may be effective against some viral and bacterial infections (Bauer et al. 1990; Schulthess et al. 1991; Leung and Foster 1996; Burger et al. 1997; Cox 1998). Scaglione and Lund (1995) observed that an anti-cold remedy including E. purpurea was effective for the treatment of common cold and it shortened the healing time. Echinacin, a product made from the juice of fresh plant tops, has been produced for 50 years and subjected to more than 150 clinical studies in Germany (Hobbs 1989). Echinacea products are medically prescribed in Germany (Blumenthal 1998; Hobbs 1989; Leslie 1995, 1996). In the US, many health remedies or dietary supplements include echinacea in the form of dry root, capsules, tablets, crude extracts, tinctures, and are mainly from E. purpurea and E. angustifolia (Leung and Foster 1996; Li 1998). Injectable preparations using echinacea extracts are available only in Germany (Li 1998). Echinacea products can also be found combined with other medicinal herbs yet in the US, but the product label is not allowed to have specific therapeutic claims (Li 1998). McCaleb (1998) reported that the squeezed sap of Echinacea purpurea L. (Echinacinâ, Madaus AG, Cologne, Germany) is well tolerated and appropriate for long term-oral use, with no adverse reaction observed other than aversion to the taste during oral use for up to 12 weeks. Even injections were found to be safe for both adults and infants. Some rare side effects were observed such as shivering, vomiting, headache, and fever during injection treatment. Mengs et al. (1991) reported no evidence of any toxicity using E. purpurea in rats or mice during a 4-week application of single oral or intravenous doses, amounting to many times the human therapeutic dose. Tyler (1993) and Scaglione and Lund (1995) conclude that the use of echinacea is safe.
Echinacea species are also grown for their ornamental value. Samfield et al. (1991) reported that Texas wild flowers, including Echinacea species, were desirable for their low maintenance requirements, erosion control, and esthetic qualities. E. purpurea is used for wildflower establishment, perennial gardens, and as a cut flower (Wartidiningish and Geneve 1994). E. purpurea is reported to be a good landscape plant since its flower color ranges from white to rose-pink to red-violet so that it can associate with everything from pale yellows to blues or reds (Cox 1998). Echinacea purpurea, with average 18 stems and 47 cm stem length per plant was reported as one of the most profitable perennial cut flowers without major pest or post harvest problems while E. angustifolia with lower stem yield (four) and stem length (24 cm) was unprofitable (Starman et al. 1995).
The largest areas of commercial cultivation of Echinacea species in North America is estimated to be in the Pacific Northwest, though actual production figures are difficult to obtain. Central and western Canada is emerging as a new production area. Commercial cultivation has increased rapidly due to increased marked demand (Li 1998), but information on cultural methods and their effect on growth, yield, and chemical composition remains limited.
One of the basic obstacles facing field production is the poor and erratic seed germination. Low seed germination percentage of Echinacea species was noted by SmithJochum and Albercht (1987, 1988). E. pallida and E. angustifolia seem to have stricter dormancy than E. purpurea. Shalaby et al. (1997) reported 70% germination from untreated E. purpurea seeds while stratification at 2°C for 40 days increased germination to 8285% and cold dry storage to 83%. However, germination of E. pallida and E. angustifolia were 01% even after stratification. Baskin et al. (1992) found that fresh mature seed of E. angustifolia germinated only from 0% to 6% when they were placed under light and from 0% to 2% when placed in darkness, but that a 12-week cold stratification at 5°C broke dormancy. In another study, no germination was observed when E. angustifolia and E. pallida were directly sown in the spring (SmithJochum and Albercht 1988). Li (1998) recommended stratification of echinacea seeds in moist sand at 1°C to 4°C and for 4 to 6 weeks. Germination of E. angustifolia using both stratified and nonstratified seeds reached 94% after treatment with 1.0 mm ethephon and 86% after treatment with 2500 mg/L GA3 at 25°C germination temperature (Sari 1999).
A second major field problem facing the echinacea production is the susceptibility of the plant to aster yellows. E. purpurea appears to be the most susceptible of all Echinacea species. The disease, caused by a phytoplasma transmitted by thrips, can been devastating. Growers have reported near complete losses in areas of heavy infestation. Resistant cultivars are not available, and control of the diseases can only be achieved by controlling the vector. Under field conditions thrip control has been difficult, and even more problematic under organic production systems. Research on genetic resistance to thrips, and sustainable control methods need to be pursued.
Fresh seed of E. angustifolia were obtained from the Prairie Moon Nursery Winoma, Minnesota. Seeds were treated as described below and stratified at 10°C for 4, 8, or 12 weeks in dishes but only the results from the 8 week stratification period are reported here. When the stratification period was complete, a subsample of all treated seeds were transferred to petri dishes containing two 90 mm Whatman filter papers (25 seeds per petri dish; with 4 petri dishes per treatment), which were placed into germination incubators at a constant temperature of 25°C. Germination from constant temperature was equal to or greater than alternating temperatures of 25° (12 h) and 15°C (12 h).
The 5 seed treatments were as follows:
|Fig. 1. Germination of Echinacea angustifolia following seed treatments with 1mM ethephon or 2500 mg/L GA3 and 8 weeks of stratification at 10°C. Seed germination conditions were at a constant 25°C.|
Our results (Fig. 1) demonstrate that germination rates of greater than 95% for E. angustifolia can be achieved when seeds are cold stratified and treated with either 1mM ethephon or 2500 mg/L GA3. High germination rates were also achieved simply by soaking the seeds in water prior to or at the time of stratification. Presoaking the seeds for 24 h improved germination compared to moistening the seeds only at the time of stratification, presumably allowing increased water imbibition. Germination after dry stratification was significantly lower than all other treatments (< 50% after 20 days). Once stratified seeds were placed into incubators, germination began by day 4. The germination percentage did not significantly increase over the 20 day counting period, except for the dry stratification seeds which reached a maximum at day 16. The results of the dry stratification appear to fall within the low range that seed companies and growers report for E. angustifolia.
Our results clearly illustrate several options to overcome seed dormancy in this species that could be of use by growers, seed companies, and nurseries. The use of ethephon or GA3 plus stratification increased seed germination more than when stratification alone was used, or when either growth regulator was used in the absence of stratification (Sari 1998).
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*J. Paper no. 15,871 of the Purdue Agricultural Research Programs, Purdue University, West Lafayette, IN. This research was supported by the Turkish Ministry of Agriculture and Rural Affairs and a grant from Quality Botanical Ingredients, Inc. We thank Larry W. Ness and Kyle W. Arvin and staff of the Office of the Indiana State Chemist and Seed Commissioner for their help and use of facilities; Jim Quinn formerly of QBI for his suggestions during the study, and to Jules Janick for his critical review.