Generality
Natural antihistamines are compounds of natural origin that can interfere with the activity of histamine, one of the main mediators involved in allergic reactions.
Natural antihistamines can exercise their activity through different mechanisms of action, but the final result will always consist in the reduction of histamine activity.
Sometimes, however, we speak of natural antihistamines even when, in fact, these substances do not exert a real antihistamine action, but an action that could be defined - in a more general way - as antiallergic.
Please note
Natural antihistamines are not drugs and cannot in any way cure allergic reactions and diseases. Therefore, in no case can natural antihistamines be considered as a substitute for antihistamine drugs and antiallergic drugs recognized and approved by modern medicine.
Antihistamines and antiallergics
Antihistamines and Antiallergics: a bit of clarity
Often, the terms "antihistamines" and "antiallergic" are used synonymously. However, this overlap of meanings - which has become commonplace - is not entirely correct.
The term " antihistamines ", in fact, is used to indicate all those substances or drugs that - in one way or another - are able to interfere with the activity of histamine, decreasing it.
With the term " antiallergic ", instead, we want to indicate a heterogeneous set of substances and drugs able to counteract the allergic reactions, acting directly on the triggering causes and / or alleviating the symptoms.
Since histamine is not the only mediator involved in allergic manifestations, when we talk about antiallergics we refer in a broad sense to:
- Antihistamines (in detail, anti-H1 and histamine release inhibitors );
- Anti-inflammatories (steroids and leukotriene inhibitors);
- Bronchodilators (β2-agonists, anticholinergics and methylxanthines);
- Decongestants .
Did you know that ...
To be fair, among the antihistamines there are not only the receptor antagonists for the H1 histamine type (anti-H1) and the histamine release inhibitors useful in case of allergic reactions, but also the H2 receptor antagonists ( anti-H2) useful in case of gastric acidity. Given the action exercised by the latter, however, they are classified as antacids; while when we talk about antihistamines we generally refer to compounds (natural or synthetic) used in case of allergic manifestations.
However, since in most cases the term "natural antihistamines" is traced back to all natural substances capable of interfering with allergic manifestations, during the article all natural remedies that are defined as such will be analyzed, even if in improper way.
In other words, the main characteristics of both what we could describe as natural antihistamines proper, and the natural antihistamines that are not exactly so called, but so defined - albeit mistakenly - in common language will be illustrated.
Quercetin
Quercetin is a flavonoid contained in different types of plants and has numerous properties. Among these, we find the ability to inhibit the release of histamine and to decrease the levels of pro-inflammatory leukotrienes . Therefore, quercetin is fully included in the group of natural antihistamines.
On the market, it is possible to find dietary supplements based on quercetin which are used as adjuvants in the reduction of symptoms induced by allergic reactions.
Please note
Not all plants containing quercetin can be included among natural antihistamines. This can be explained by the fact that quercetin is usually not present in free form in nature, but rather as an aglycone of different glycosides (eg quercitrin and rutin). In addition to this, the concentration of quercetin and its bioavailability could also affect the ability of the plants that contain it to exert any antihistamine activity.
Possible Pharmacological Interactions
Quercetin may interfere with the activity of anticoagulants and antiplatelet agents.
Contraindications
The use of quercetin is contraindicated in case of known hypersensitivity to the same substance and - as a precautionary measure for suspected mutagenic activity - during pregnancy and during lactation.
Perilla
Perilla ( Perilla frutescens ) is a plant belonging to the Labiatae family and a full member of the natural antihistamine group.
Perilla and its extracts, in fact, have been shown in various studies to be able to decrease histamine levels, thus modulating allergic reactions. In addition to this, perilla has also been shown to be capable of inhibiting the synthesis of leukotrienes (also involved in allergic manifestations) and of reducing IgE levels (implicated in the degranulation of mast cells and the consequent release of histamine).
Side effects
Perilla and its extracts can cause sensitization reactions in predisposed individuals.
Contraindications
The use of perilla and its derivatives is contraindicated in case of known hypersensitivity to the plant. Furthermore, in vitro studies have shown that this plant can exert a mutagenic action, therefore, its use in pregnancy and during lactation is contraindicated.
Blackcurrant
The black currant ( Ribes nigrum ) is a woody shrub belonging to the family of
Grossulariaceae. Blackcurrant is often referred to as the best of natural antihistamines that nature is able to offer, even if, in reality, it is not quite so.
In fact, blackcurrant and its extracts can be useful in case of allergies, not because they have an antihistamine action proper, but because they exert a steroid-like anti-inflammatory action, therefore an action that is able to modulate the immune system response.
In this regard, many argue that taking blackcurrant supplements one or two months before critical periods to trigger allergies (generally spring and autumn), can somehow help reduce attacks allergic in predisposed individuals.
Contraindications
The use of blackcurrant supplements is contraindicated in case of known hypersensitivity to the blackcurrant itself and in patients suffering from edema induced by renal and / or cardiac function impairment. Furthermore, as a precautionary measure, it is advisable not to take blackcurrant and its derivatives even during pregnancy and lactation.
Licorice
Licorice ( Glycyrrhiza glabra ) is a plant belonging to the Leguminosae family and famous above all for its anti-inflammatory, protective properties on the gastric mucosa, expectorant and hypertensive .
However, what many people do not know is that licorice also belongs to the group of natural antihistamines. Studies conducted on the glycyrrhizin contained in it, have shown that this compound is able to inhibit the degranulation of mast cells, therefore, the consequent release of histamine.
However, liquorice-based food supplements are used mostly to maintain the well - being of the gastrointestinal mucosa and respiratory tract .
Possible Pharmacological Interactions
Licorice may interfere with the activity of diuretic and laxative drugs, anti-inflammatories (both NSAIDs and steroids), anti-arrhythmics and digitalis, oral contraceptives and insulin.
Side effects
Following prolonged use of licorice or its derivatives, hypertension, hypokalemia, arrhythmias and sodium retention may occur.
Contraindications
Given its many properties and the mechanisms of action by which they are exercised, the use of licorice and its derivatives is contraindicated in the following cases:
- Ascertained hypersensitivity to one or more plant components;
- Hypertension;
- Hypokalemia;
- Salt and water retention;
- Body overweight;
- Severe hepatic failure and / or liver cirrhosis;
- Severe renal failure;
- Cardiac arrhythmias;
- Diabetes mellitus;
- Neuromuscular disorders;
- In pregnancy and during lactation.
feverfew
The parthenon ( Tanacetum parthenium ) is a plant belonging to the Asteraceae family, known above all for its anti-inflammatory and anti- migraine properties .
However, a study carried out on animals has shown that the extract of parthenion in chloroform is able to reduce the release of histamine from mast cells, but the exact mechanism by which this occurs is still unknown.
However, despite the results obtained from the aforementioned studies, dietary supplements based on feverfew are not used as potential natural antihistamines, but are used mostly as a remedy against migraine.
Possible Pharmacological Interactions
Parthenion may interfere with the activity of NSAIDs, oral anticoagulants and antiplatelet agents.
Side effects
Following the intake of feverfew and its derivatives, undesirable effects such as vomiting, diarrhea, insomnia and headache may occur.
Contraindications
The use of feverfew and its derivatives is contraindicated in case of known hypersensitivity to the plant, in patients suffering from gastritis and / or gastrointestinal ulcer, in pediatric age, during pregnancy and lactation.
Homeopathic Remedies
Homeopathy offers several natural products that are often referred to as "natural homeopathic antihistamines". Of course, even in this case, the use of the name "natural antihistamines" is not absolutely appropriate. Indeed, it is not possible to say that there is a homeopathic remedy capable of countering the release of histamine or its activity. More than anything else, according to the principle of "similar care the like", homeopathy proposes several remedies to be used in the treatment of various types of allergies. These include:
- Histaminum hidrochloricum : considered the homeopathic antihistamine remedy par excellence, it is obtained precisely from histamine, the mediator implicated in allergic manifestations. The use of this remedy is indicated in case of allergic contact inflammation, inhalation or ingestion.
- Euphrasia officinalis : homeopathic remedy of vegetable origin that is used in the treatment of pollen allergies and, in particular, in rhinitis and allergic conjunctivitis.
- Blatta orientalis : is a homeopathic remedy of animal origin indicated in case of asthmatic crisis induced by allergies to dust mites and / or molds.
Please note
The practices described above are not accepted by medical science, have not been subjected to experimental tests conducted with scientific methods or have not passed them, therefore such practices could be ineffective or even be dangerous to health .
The information given is for illustrative purposes only.
In case of allergic manifestations of any kind, before taking natural antihistamines of any kind, it is necessary and essential to contact your doctor.
