Alkylamides from Echinacea modulate induced immune responses in macrophages

The ability od Echinacea and its components to alter the immune response was examined in vitro in a macrophage cell line under either basal or immunostimulated conditions. Potential immunostimulatory and inflammatory activity was determined using a nuclear transciption factor (NK kappa B) expression, tumour necrosis factor alpha (TNF alpha) and nitirc oxide (NO) production as biomarkers. In the absence of alternate stimulation, the only significant effects seen were a decrease in KF kappa B expression by a 2-ene alkylamide ((2E)-N-isobutylundeca-2-ene-8,10-diynamide (1)) and a decrease in TNF alpha levels by cichoric acid and an Echinacea alkylamide fraction (EPL AA). When the cells were stimulated by lipopolysaccharide (LPS), inhibition of the increased NF kappa B expression levels was caused by cichoric acid, an Echinacea preparation (EPL), EPL AA and a 2,4-diene ((2E, 4E, 8Z, 10Z)-N-isobutyldodeca-2,4,8,10-tetraenamide (2)). Increases in TNF alpha levels were inhibited by cichoric acid, EPL and EPL AA but enhanced by 1 in the presence of LPS, while only EPL AA was able to inhibit the stimulated increases in NO. When using phorbol myristate acetate to stimulate the cells, NF kappa B and NO levels were unaffected by Echinacea or its components while only cichoric acid and 2 inhibited TNF alpha levels. Although cichoric acid was found to have an effect, it is probably not an important contributor to the Echinacea modulation of the immune response of the macrophages to an immune stimulus and its combination of phytochemicals exhibits different pharmacological properties to one or more of the isolated major individual components.