Herbal teas in an Italian herbalist's shop: how they are formulated and prepared
In the previous article we did a general framing of what an herbal tea is, as it is defined at a regulatory level, which species of medicinal plants can contain and which are not (Belfrit list). Now let's get to the heart of the matter: as an herbalist technician or a pharmacist formulates an herbal tea and the various preparation methods defined in the Italian Pharmacopoeia.
How do you make an herbal tea?
The "species ad tisanas", according to the WHO should not contain more than four, five or at most six officinal plants. Too many drugs make a "minestrone", not an herbal tea, and if you don't know the officinal plants well, you run the risk of putting together tannins, mucilages, sterols and then inactivating everything. Exceptions to this rule are expectorant and purifying teas, in which different drugs can be placed, even ten or twenty. The preparation of species for herbal teas follows very specific canons, in fact other drugs with various properties (synergistic, adjuvant, corrective, ..) are mixed with the drugs that make up the basic remedy. In a mixture composed for herbal tea we distinguish:
1) Cardinal remedy or Basic remedy: the plant or plants that take the role of guiding action;
2) Adjuvans o Adjuvant: the plant or plants which, by synergy, reinforce the action of the first remedy or compensate, with a similar action, for any potentially unfavorable side effects;
3) Constituens or Complement: to complete, eventually, the accessory actions of the herbal tea;
4) Corrigens or Corrector: for the pleasantness, the appearance and the acceptability of the herbal tea.
For the proportions: out of a total of 100%, the basic remedy will be added to 60% (if there were two cardinal drugs, 30% and 30% will be added, if there were 3 drugs in the formulation they will be added to 20%, 20 %, 20%), 20% adjuvant, 10% complement and 10% concealer.
How to prepare an herbal tea?
The solvent used is by definition water. The most commonly used method is that of infusion, which follows the way in which the tea is infused: boiling water is poured over dry vegetable drugs (see above), allowed to infuse for 5-10 minutes and filtered. In addition to this classic infusion method, in some cases it can be used for decoction, or for maceration or digestion.
The parameters to be taken into consideration are: quantity of drug to be used for a given quantity of liquid, cutting of the vegetable drug (shredding degree: 4 mm for leaves, flowers, aerial parts, from sieve 2800 to 4000 for bark and roots, sieve) 2000 for seeds), method and duration of extraction.
Regarding the extraction methods:
- infusion: it is the most used, an infusion is a liquid preparation obtained extemporaneously, pouring on dry drugs, reduced to a convenient degree of subdivision and from which we want to extract the active ingredients, water (reagent) (150 or 250 ml) to T of boiling and then leaving in contact with the water itself for a longer or shorter time, in a glass or porcelain container, covering and stirring occasionally, to then filter after 5-10 minutes. An infusion is therefore particularly suitable for leaves, flowers and aerial parts (grass). After complete cooling, filter through cotton wool or gauze, without compressing; bring the filtrate to the prescribed mass with warm water (reagent) with which the residue and filter are washed. Generally, 1 to 10 parts of the drug are used for the preparation of 100 parts of infusion.
Infusion is an extraction technique that is applied when the drug consists of soft and delicate tissues, such as leaves and flowers, twigs and other aerial parts of the plant; depending on the type of drug used, the infusion lasts for 10-20 minutes, usually until cooling. The infusion time, even if important, does not allow to extract the poorly soluble substances in water (only 10-15% of the oil present in the chamomile passes into the infusion even after a prolonged extraction time).
- decoction: a decoction is a liquid preparation obtained extemporaneously by boiling the appropriately powdered drugs in water, from which the active ingredients are to be extracted. In practice, this is how it is obtained: the quantity of drug is put into cold water, it is heated to boiling, it is left to boil for 5-10 minutes, it is left to rest and filtered.
Particularly suitable for barks, woods and roots, especially if rich in tannins. It never applies to drugs containing volatile active ingredients. Usually 5 parts of drug are used to prepare 100 parts of decoction.
- maceration: cold water is poured over the prescribed amount of drugs and left to soak for 30 minutes to 4 hours or even overnight, and in any case according to the rules established for each individual plant.
Particularly suitable for mucilaginous drugs (in particular flax seeds, marshmallow) or when you want to avoid extracting unwanted substances: for example in case of bearberry, compared to the decoction, the macerated is preferable as it allows to obtain a greater quantity of arbutin and a smaller amount of tannins. It must be consumed quickly because, not having undergone heating, it already has a high bacterial load from the start. This method is also used for woody or hardly "imbibible" drugs. Usually, after filtration, it is drunk at room temperature or after a slight heating. Generally it is prepared with these methods, that is cold, also the tisane of mistletoe, mallow, nettle leaves, dandelion root;
- digestion: it is a hot maceration (about 40 ° - 60 ° C), therefore faster, but not suitable for plants with active ingredients sensitive to heat.
The efficacy of an herbal tea depends very much on the methods of preparation, on the respect of the doses, on the time of infusion or decoction, on the dosage.
The herbal teas made from officinal plants can be used effectively as adjuvants in the treatment of diarrhea, constipation, bronchitis, catarrhous coughs, difficult digestions, abdominal spasms, colitis, dysmenorrhea, amenorrhea, difficulty in falling asleep, detoxifying and as adjuvants also in the treatment of more complex diseases like diabetes, hypertension, lithiasis, hepatic and renal insufficiency.
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Fitoterapia per il farmacista, P. Chiereghin, 2005, Ed. Tecniche Nuove
Manuale delle preparazioni erboristiche, F. Bettiol, 2009, Tecniche Nuove