Purple coneflower (Echinacea purpurea) and Infection (general): evidence and sources

The research study in this review represents the largest clinical trial to date that evaluated the safety and efficacy of Echinacea purpurea for prophylactic treatment of the common cold, in addition to investigating its risk-benefit in a long-term treatment period. The clinical application of the proprietary standardized Echinacea purpurea extract(Echinaforce) demonstrated efficacy as a preventive cold treatment option over a 4-month duration. This study showed that Echinacea’s long-term prevention was associated with a reduction in the total number of cold episodes, a reduction in the number of days with colds, and a reduction in cold episodes requiring additional medication. Furthermore, the Echinacea test agent inhibited virally confirmed colds, exhibited maximal effects on recurrent infections, and demonstrated that its preventive effects increased relative to therapy compliance and adherence to the protocol. In summary, Echinacea purpurea when taken as recommended for the prevention of the common cold appears to provide a positive risk to benefit ratio.

Extracts of Echinacea purpurea (EP, purple coneflower) have been used traditionally in North America for the treatment of various types of infections and wounds, and they have become very popular herbal medicines globally. Recent studies have revealed that certain standardized preparations contain potent and selective antiviral and antimicrobial activities. In addition, they display multiple immune-modulatory activities, comprising stimulation of certain immune functions such as phagocytic activity of macrophages and suppression of the proinflammatory responses of epithelial cells to viruses and bacteria, which are manifested as alterations in secretion of various cytokines and chemokines. These immune modulations result from upregulation or downregulation of the relevant genes and their transcription factors. All these bioactivities can be demonstrated at noncytotoxic concentrations of extract and appear to be due to multiple components rather than the individual chemical compounds that characterize Echinacea extracts. Potential applications of the bioactive extracts may go beyond their traditional uses.

Echinacea purpurea (L.) Moench was mistakenly taken from North America to Germany in 1939 where it was cultivated and various extractions were prepared and subsequently used to treat upper respiratory tract infections. Parents often administer Echinacea to their children, but safety data on the use of Echinacea in Canadian children is lacking. A screening history, physical examination, and daily record of symptoms from an initial visit through to a the follow-up visit 13 days later were used to increase patient safety. Each subject was administered an aerial part Echinacea extract. The dose was based on age (2.5 mL three times per day for children aged 2-5 years, and 5 mL two times per day for children aged 6-12 years) and administered for 10 days in an open-label trial. A rating scale was used to measure tolerance to the treatment. We assessed the safety and compliance of use of the Echinacea extract by measuring the amount of extract returned at the end of the study, having the parents complete and return a daily symptom diary, and recording the subjects' use of other natural health products or medications during the trial. Clinical effectiveness of the Echinacea extract could not be accurately assessed because of the small trial size and because the extract had been administered when some of the subjects had an upper respiratory tract infection that had begun 1 or more days prior to the study; however, each subject's symptoms improved. No allergic or adverse reaction occurred and no safety issues arose.