Immunomodulatory effects of Echinacea laevigata ethanol tinctures produced from different organs

Abstract

Echinacea supplements may prevent or reduce symptoms of upper respiratory infections by immunomodulation, possibly by altering the cytokine profile. Compared with other species in the genus, the immunomodulatory properties of Echinacea laeviagata are poorly characterized. The purposes of this study were to compare the diversity and quantity of known bioactive compounds from aboveground organs of E. laevigata, and to characterize the in vitro immumodulatory properties of ethanol tinctures produced from those structures. High-performance liquid chromatography (HPLC) was used to determine the levels of alkamides and caffeic acid derivatives. Peripheral blood mononuclear cells (PBMCs) were obtained from 16 adults and challenged in vitro with extracts. PBMC proliferation and production of the cytokines interleukin-2 (IL-2), IL-10 and tumour necrosis factor-a (TNF-α) were measured. Fresh flower, leaf and root extracts were able to augment TNF and IL-10 and proliferation, whereas fresh stem extract was only able to augment TNF. Extracts produced from flowers contained the greatest bioactive compound quantities and diversity. Caftaric acid was the most abundant compound and correlated with some (but not all) observed immune effects. These results suggest that of all aboveground parts, flowers have the greatest abundance and diversity of known bioactive compounds, and both flower and leaf extracts were immunomodulators.