Echinacea is a perennial herbaceous plant that includes at least 9 species, is part of the family Asteracee and is native to North America. Its name comes from the Greek echinos (hedgehog), probably derived from the shape or aerial structure of the plant. As already said, the origin is from North America but to be considered in all its extension, including Mexico, it possesses a remarkable capacity of adaptation even if privileging places at higher altitudes, aerated and sunny.
Its therapeutic properties have been known since ancient times when it was mainly used the rhizome in particular as scarring and anti-infective, especially in the wounds and ailments of the skin, even from traumas.
This plant, in particular its roots, has reached increasing notoriety because of its supposed capacity of strengthening/ stimulation of the immune system. Of course, at a time like the one we’re experiencing, when the full activity and integrity of the immune system is rightly considered the main defence against virus aggression - for which, as we now know, A healthy immune system is the main defence -, this type of property has aroused a resounding interest.
There are many commercial preparations that contain the various extracts of different species of ECHINACEA, proposed for many years as a shield against various diseases and different "cooling diseases"small pathologies mostly seasonal caused by viruses and bacteria that mainly attack the upper airways.
But is the treatment/support strategy that sees the use of the various pharmaceutical forms based on Echinacea really effective?
Let’s briefly examine the most recent scientific literature: first of all, it is good to consider, for the purpose of knowledge, the chemical composition of the extracts used, keeping well in mind the concept of Phyto complex. In fact, in the field of phytotherapy, the pharmacological activity of medicinal plants is not given by an isolated active ingredient, as is the case in most drugs, but by a set of compounds that frequently act in synergy, modulating the activity of the plant and proposing pharmacological activities sometimes different from those of the individual substances.
Let’s take the example of caffeine: we know the organic activities related to its intake, if we compare them with the same amount of caffeine present, eg. In the guarana, these are presented with different characteristics given just by the Phyto complex that modulates the action decreasing the acute response but also acts on the half-life minimizing side effects.
In essence, this is the "2-sided" effect of herbal products: minor side effects but great difficulties to assess the actual capacities of the pharmacological effect because of the impossibility to bind a substance present to the effectiveness given instead by the Phyto complex.
These considerations also lead to the need to assess the different efficacy of products based on medicinal plants because, due to the diversity of composition of the plant and the different qualities of these (a quality which in turn depends on other factors such as different cultivation soil, different growing environment, best harvesting years depending on the weather, time of harvest of the plant, etc.).
In any case, to return to the characteristics of the Echinacea, the present knowledge has evidenced those that are the main constituents for the pharmacological purposes of the Phyto complex and, between these, we find several essential oils.
Clearly, the percentage of these substances also varies according to the species considered. Flavonoids, derivatives of caffeic acid (cicoric acid, chlorogenic acid and echinacoside), polyphenols, alkyl amides and various glycoproteins and polysaccharides to which are attributed the immunostimulating properties (inulin, arabinogalactans and heteroxylans), in particular, are evidenced, for therapeutic purpose, especially 3 species: Echinacea Angustifolia, Echinacea pallida and Echinacea purpurea.
In 2005 J. Barnes and coll. An analysis of the literature has highlighted one aspect: in substance rather than an immunostimulating activity is certainly recognized as an immunomodulatory activity evaluated by both "in vitro" and "in vivo" experiments in particular on the activity of macrophages. There is also a support activity to that of TNFa and IL-1 and IL-10 as well as Interferon; these results are a contrast to others in which there are no supports to the activity of "natural-killers" or to the formation of antibodies. Because of this distinction of effects, some authors recommend a regular intake of echinacea preparations for at least 4 months for prophylactic rather than curative purposes, enhancing the concept of immunomodulation.
Promising data support an antiviral activity of echinacea extracts, several studies have compared them with aciclovir obtaining overlapping data. But there are very few supporting studies.
Equally interesting is the antifungal and antibacterial activity, in particular, the first was studied by evaluating the ability to inhibit the growth of saccharines with good results but, above all, against the candida Albicans, obtaining excellent results. Similarly, the antibacterial capacity was tested in vitro on cultures of Escherichia coli, Proteus mirabilis, Pseudomonas aeruginosa and Staphylococcus aureus obtaining uncertain results, in some cases excellent but were derived from products of different mixed herbs. The main problem is a shortage of available studies.
The anti-inflammatory and healing activities typical of the popular tradition have been confirmed, even if only for the products to be used locally as gels and ointments.
The data on side effects are not very clear, as well as several interactions with other drugs related to the interaction with cytochromes responsible for the organic transformation of drugs have been reported.
Ultimately, in these reviews, the immunomodulatory ability in the various conditions of use is highlighted, in particular, in the treatment of respiratory infections of the upper airways (URTI) the validity of which is reported by several dozen different studies although it remains the fundamental problem related to the difficulties in conducting pharmacokinetic and pharmacodynamic studies so that the clinical results are affected by the lack of these studies, therefore, it is difficult to obtain conclusive results in the various clinical trials.
In conclusion, while reaffirming interesting properties in terms of prevention and reduction of recovery times in the treatment of seasonal illnesses, The difficulties in framing the safe therapeutic characteristics are confirmed by the difficulties in standardizing studies, as is typically the case with phytotherapeutic products.
Echinacea for preventing and treating the common cold. Karsch-Völk M, Barrett B, Kiefer D, Bauer R, Ardjomand-Woelkart K, Linde K. Cochrane Database Syst Rev. 2014 Feb 20;2(2):CD000530
Echinacea plants as antioxidant and antibacterial agents: From traditional medicine to biotechnological applications. Sharifi-Rad M, Mnayer D, Morais-Braga MFB, Carneiro JNP, Bezerra CF, Coutinho HDM, Salehi B, Martorell M, Del Mar Contreras M, Soltani-Nejad A, Uribe YAH, Yousaf Z, Iriti M, Sharifi-Rad J. Phytother Res. 2018 Sep;32(9):1653-1663. doi: 10.1002/ptr.6101
Echinacea for the prevention and treatment of upper respiratory tract infections: A systematic review and meta-analysis. David S, Cunningham R. Complement Ther Med. 2019 Jun;44:18-26.
Studies on phytochemical, antioxidant, anti-inflammatory, hypoglycaemic and antiproliferative activities of Echinacea purpurea and Echinacea angustifolia extracts. Aarland RC, Bañuelos-Hernández AE, Fragoso-Serrano M, Sierra-Palacios ED, Díaz de León-Sánchez F, Pérez-Flores LJ, Rivera-Cabrera F, Mendoza-Espinoza JA. Pharm Biol. 2017 Dec;55(1):649-656
Can Echinacea be a potential candidate to target immunity, inflammation, and infection - The trinity of coronavirus disease 2019. M F Nagoor Meeran, Hayate Javed, Charu Sharma, Sameer N Goyal, Sanjay Kumar, Niraj Kumar Jha, Shreesh Ojha; Heliyon. 2021 Feb;7(2):e05990.
Echinacea species (Echinacea angustifolia (DC.) Hell., Echinacea pallida (Nutt.) Nutt.,Echinacea purpurea (L.) Moench): a review of their chemistry, pharmacology and clinical properties. Barnes J, Anderson LA, Gibbons S, Phillipson JD. J Pharm Pharmacol. 2005 Aug;57(8):929-54