Echinacea extracts modulate the pattern of chemokine and cytokine secretion in rhinovirus-infected and uninfected epithelial cells

Extracts of Echinacea purpurea are among the most widely used herbal medicines throughout Europe and North America for the prevention or treatment of common cold, coughs, bronchitis and other upper respiratory infections. Popular preparations include expressed juice from the aerial parts of the plant (which contain polysaccharides) and alcoholic tinctures from roots (containing caffeic acid derivatives and alkylamides). Since immune modulation has been reported for similar extracts, cytokine antibody arrays were used to investigate the changes in the pro-inflammatory cytokines and chemokines released from a cultured line of human bronchial epithelial cells exposed to Rhinovirus 14 and two different chemically characterized Echinacea extracts. Virus infection stimulated the release of at least 31 cytokine-related molecules, including several important chemokines known to attract inflammatory cells. Most of these effects were reversed by simultaneous exposure to either of the two Echinacea extracts, although the patterns of response were different for the two extracts. These results could explain the antiinflammatory properties of Echinacea extracts. Furthermore, a number of these cytokines were stimulated by the same Echinacea preparations in uninfected cells. These observations therefore provide support for the alleged beneficial uses of Echinacea extracts. Copyright (c) 2006 John Wiley & Sons, Ltd.