Echinacea (Echinacea angustifolia/purpurea)

Echinacea is particularly valued for its ability to enhance immune function. Studies show that Echinacea increases the activity of white blood cells, including natural killer cells and monocytes, which are essential for combating infections (Goel et al., 2005). Polysaccharides in Echinacea, such as heteroxylan and arabinogalactan, are key contributors to this immune-enhancing effect by promoting the production of immune cells and cytokines like interleukin-1 and tumour necrosis factor (Wagner, 1988; WHO, 1999; Mills & Bone, 2013). Moreover, Echinacea intake has been linked to increased expression of leukocyte heat shock proteins (hsp70), which play a crucial role in immune regulation (Roesler et al., 1991, as cited in WHO, 1999).

The anti-inflammatory effects of Echinacea make it beneficial for treating inflammatory conditions such as sore throats, ear infections and inflammatory skin conditions. It works by inhibiting the enzyme hyaluronidase, which breaks down hyaluronic acid, a vital component of connective tissue, thereby reducing inflammation and promoting tissue healing (Büsing, 1952, as cited in WHO, 1999; McIntyre, 2019). Additionally, alkylamides found in Echinacea have been shown to inhibit the activity of 5-lipoxygenase, further contributing to its anti-inflammatory properties (Wagner et al., 1988). In clinical settings, Echinacea has also been demonstrated to effectively reduce the inflammatory response in patients with upper respiratory infections (Barrett et al., 2010).

Echinacea has demonstrated significant antiviral properties, particularly in inhibiting the replication of various strains of influenza virus and other respiratory pathogens. Its effectiveness is most pronounced when used at the onset of infection, helping to prevent viruses from penetrating cells and establishing infection (Buhner, 2012; Mills & Bone, 2013; WHO, 1999). In vitro studies have also shown that chicoric acid, a compound found in Echinacea purpurea, can inhibit viral replication by more than 50% (Müller-Jakic et al., 1994). Additionally, a randomised controlled trial found that Echinacea was effective in reducing the incidence and severity of colds and respiratory infections (Schöneberger, 1992, as cited in WHO, 1999).

Echinacea's antiseptic properties make it highly effective when applied topically to treat burns, wounds, and other skin conditions. The herb's ability to prevent infection and promote healing has been well documented, making it a valuable natural remedy for skin ailments (Viehmann, 1978, as cited in WHO, 1999; McIntyre, 2019). For example, an ointment containing Echinacea purpurea was found to significantly improve healing in 85.5% of cases involving inflammatory skin conditions, burns, and wounds (Viehmann, 1978, as cited in WHO, 1999). Furthermore, Echinacea-based treatments have shown efficacy in managing herpes simplex virus outbreaks and in promoting wound healing by stimulating fibroblast activity (WHO, 1999).

As previously mentioned, echinacea is commonly used to relieve symptoms of upper respiratory tract infections. It has been shown to reduce the duration and severity of symptoms by stimulating immune activity and inhibiting the growth of pathogens that cause these infections (Barrett et al., 2010; WHO, 1999; Mills & Bone, 2013). Clinical trials have demonstrated that Echinacea purpurea is effective in preventing and treating colds, particularly in individuals exposed to stress, such as athletes (Schöneberger, 1992; Barrett et al., 2010). Additionally, the herb's ability to enhance phagocytosis and stimulate the production of interferon further supports its role in respiratory health (WHO, 1999).