Echinacea and anti-inflammatory cytokine responses: Results of a gene and protein array analysis

Abstract

Preparations of Echinacea (Asteraceae) are frequently consumed for the control and prevention of rhinovirus-induced colds and other respiratory disorders. Since it is now generally believed that the symptoms of rhinovirus colds are due to the enhanced secretion of inflammatory chemokines and cytokines, we decided to analyze the effects of rhinovirus infection and Echinacea treatment [defined extracts of E. purpurea (L.) Moench] on cytokine/chemokine gene expression and protein secretion in a line of human tracheo- bronchial epithelial cells. Among the collection of more than 50 cytokines and chemokines present in the gene arrays, 12 showed significant induction of expression by the virus (> 2-fold), some of them by more than 5-fold. However, not all of these resulted in similar changes in the corresponding proteins, presumably as a consequence of post-transcriptional changes. A total of 16 cytokines, mostly chemokines, showed substantial protein increases, including several, such as the well known pro-inflammatory cytokines IL-6 and IL-8 (CXCL8), which were induced in the absence of additional transcription. These results support the concept that virus-induced multiple inflammatory cytokines are responsible for the cold symptoms. In most cases, one or both Echinacea preparations reversed the viral stimulation, thus providing a basis for the anti-inflammatory properties attributed to Echinacea.