The multiple actions of the phytomedicine Echinacea in the treatment of colds and flu

Abstract

The symptoms of cold and flu are generally attributed to specific respiratory viruses and bacteria acting either as primary agents, or as secondary agents following a viral infection. These infections can induce the secretion of pro-inflammatory cytokines by various airway epithelial cells and in conjunction with other inflammatory mediators, thereby producing the familiar symptoms of a cold or flu. Certain types of Echinacea (family Asteraceae) extract, but not all, were found to inactivate different viruses, such as rhinoviruses and influenza viruses (including Tamiflu-resistant strains) and herpes simplex virus (“cold sores”), as well as certain respiratory bacteria, including Streptococcus pyogenes (sore throat) and Hemophilus influenzae. In addition, infection of cultured epithelial cells and tissues by viruses and bacteria, induced the secretion of pro-inflammatory cytokines such as IL-6, IL-8, TNFa and excessive mucin secretion. These cellular responses were reversed by exposure to the active Echinacea extracts. Thus certainEchinacea extracts could provide multiple benefits to cold and flu sufferers, such as inactivation of the viruses themselves, inactivation of certain pathogenic respiratory bacteria and reversal of the pro-inflammatory responses induced by cold and flu agents. These extracts did not produce cytopathic effects in cultured epithelial cells and tissues. Key words: Echinacea, antiviral, antibacterial, anti-inflammatory, influenza, colds.