Abstract
Echinacea
species are used for beneficial effects on immune function, and various prevalent phytochemicals have immunomodulatory effects. Using a commercial
E. purpurea
(L.) Moench product, we have evaluated the myelopoietic effect on bone marrow of rats treated with various extracts and correlated this with their chemical class composition. Granulocyte/macrophage-colony forming cells (GM-CFCs) from femurs of female Sprague-Dawley rats were assessed at 24 h after 7 daily oral treatments. A 75% ethanolic extract at 50 mg dried weight (derived from 227 mg aerial parts) per kg body weight increased GM-CFCs by 70% but at 100 mg/kg was without effect. Ethanolic extracts from aerial parts of
E. angustifolia
DC. var.
angustifolia
and
E. purpurea
from the US-DA North Central Regional Plant Introduction Station increased GM-CFCs by 3- and 2-fold, respectively, at 200 mg/kg (~ 1400 mg/kg plant material). Extract from another USDA
E. angustifolia
was inactive. Proton and APT NMR, MS, and TLC indicated alkylamides and caffeic-acid derivatives (CADs) present in ethanolic extracts of both the 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 the commercial material exhibited polysaccharide and CAD signatures and was without effect on GM-CFCs. A methanol-CHCl
3
fraction of commercial source, 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 have demonstrated an 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.