Title: Effects of chemically characterized fractions from aerial parts of Echinacea purpurea and E. angustifolia on Myelopoiesis in Rats Authors
|Ramasahayam, Sindhura -|
|Baraka, Hany -|
|Abdel Bar, Fatma -|
|El Sayed, Khalid -|
|Meyer, Sharon -|
Submitted to: Planta Medica
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 15, 2011
Publication Date: August 25, 2011
Citation: Ramasahayam, S., Baraka, H.N., Abdel Bar, F.M., Widrlechner, M.P., El Sayed, K.A., Meyer, S.A. 2011. Effects of chemically characterized fractions from aerial parts of Echinacea purpurea and E. angustifolia on Myelopoiesis in Rats. Planta Medica. 77:1883-1889. Available online at http://dx.doi.org/10.1055/s-0031-1279990. Interpretive Summary: Echinacea is an herbal supplement widely used to treat colds and improve immune function, but many aspects of its activity aren't well understood. Tests of different Echinacea species and different sources within species often lead to divergent outcomes. We tested extracts from a commercial Echinacea purpurea product and from three known-source Echinacea populations grown at the USDA North Central Regional Plant Introduction Station for their ability to enhance production of granulocyte/macrophage-colony forming cells (GM-CFCs) in the bones of rats. These cells are important in the functioning of the immune system. When an ethanol extract of the commercial product was given to rats at 50 mg/kg, GM-CFCs increased by 70%, but a 100 mg/kg dose had no effect. Of the USDA populations (E. angustifolia, PI 649026 & 649029, and E. purpurea, PI 649040), the ethanol extract of PI 649026 was most active, giving a three-fold increase in GM-CFCs at 200 mg/kg. We used a range of analytical techniques to identify chemical compounds present in these extracts. Caffeic-acid derivatives (CADs) and alkylamides were found in ethanol extracts of both commercial and USDA-derived material. Cichoric and caftaric acids were common in E. purpurea ethanol extracts, but absent in angustifolia. CADs and polysaccharides were found in a water extract of the commercial sample, but had no effect on GM-CFCs. Fatty acids were found in polar extracts of the commercial material, but not in USDA samples. We determined that GM-CFCs are stimulated by ethanol extracts of Echinacea and this effect may counteracted by fatty acids, presumably derived from non-plant additives. These results contribute to our understanding of Echinacea's bioactivity and can be used to optimize formulations of Echinacea supplements.
Technical Abstract: Echinacea is used to improve immune function, and its chemical constituents have immunomodulatory effects. Using a commercial E. purpurea product, we evaluated the myelopoietic effect on bone marrow of rats treated with various extracts and correlated this with their chemical composition. Granulocyte/macrophage-colony forming cells (GM-CFCs) from female Sprague-Dawley rat femurs were assessed 24 hr after 7 daily oral treatments. A 75% ethanolic extract at 50 mg dried weight per kg body weight increased GM-CFCs by 70%, but at 100 mg/kg was without effect. Myelostimulation by commercial product was compared to ethanolic extracts from aerial parts of E. angustifolia (PI 649026 and 649029) and E. purpurea (PI 649040) from the USDA North Central Regional Plant Introduction Station. PI 649026 and PI 649040 at high dose (200 mg/kg) yielded 3× and 2× GM-CFCs of vehicle-treated rats, respectively, while PI 649029 was ineffective. NMR, MS and TLC revealed alkylamides and caffeic-acid derivatives (CADs) in ethanolic extracts of both commercial and USDA-derived material. Cichoric and caftaric acids were prominent in both E. purpurea ethanolic extracts, but absent in E. angustifolia. Aqueous extract of commercial material exhibited CAD and polysaccharide signatures but had no effect on GM-CFCs. A methanol-CHCl3 commercial fraction, also inactive, was almost exclusively 1:4 nonanoic:decanoic acids, which were also abundant in commercial ethanolic extract, but absent from USDA material. In conclusion, we demonstrated ethanol-extractable myelostimulatory activity in Echinacea aerial parts that, when obtained from commercial herbal supplements, may be antagonized by medium-chain fatty acids presumably derived from a non-plant additive.