We often hear the expression ‘plant extracts‘, especially in cosmetics, pharmacy, herbal medicine and phytotherapy. But do you really know what exactly is meant? What are they and what are they for?
Let’s try to find out more in this guide.
What are plant extracts
These are solutions rich in active ingredients, used in the pharmaceutical, cosmetic and phytotherapeutic fields.
They can be liquid, solid or soft preparations, obtained starting from vegetable raw materials, which are usually dried, but can also be fresh.
The various extracts are distinguished according to the type of solvent used for the extraction of the active ingredients which will consequently determine their application.
To understand: a mother tincture of burdock, an oil of hypericum or an essential oil of birch, a shea butter, are different preparations with different cosmetic and therapeutic actions and contain different active ingredients.
The production of any plant extract begins with the selection of the natural active, that is the part of the plant to be used. At this point, these parts are subjected to specific extraction processes using appropriate solvents.
The extraction process can isolate, concentrate or remove certain components from the starting plant part.
How the plant extracts are prepared
The preparation of the extract takes place in two distinct moments:
- extraction: a process that involves the use of appropriate solvents as well as the use of maceration, percolation or other suitable procedures
- concentration: through the evaporation of the solvent, the extract is made more concentrated
Types of plant extracts
Based on the plant from which the active substances are to be extracted, specific solvents are used.
The extracts (liquid, soft and dry) are obtained from maceration in different types of solvents, which are then progressively eliminated. Regardless of the type of solvent, its elimination takes place up to the concentration of the active principle to be obtained. Elimination must be achieved through procedures that preserve the active ingredient.
Depending on the solvent used, plant extracts are classified into various product categories.
- Aqueous plant extracts. Prepare by macerating a base of dry or fresh medicinal herbs in water to extract the water-soluble and thermolabile active ingredients of dry or fresh plants. They are difficult to keep.
- Glycerine and hydro-glycerine extracts. Obtained by maceration in glycerin alone or with the addition of distilled water. They are reserved for the extraction of water-soluble and glycerol-soluble active ingredients. They keep for weeks. This procedure is generally used to extract the active ingredients from particularly delicate plants, even the buds (they are then called bud extracts), which would be damaged during the process.
- Hydro-glycerol-alcoholic extracts. Obtained using a percentage of alcohol as a solvent, together with glycerin.
- Hydro-alcoholic extracts. Obtained by macerating dry plants in water and a percentage of alcohol to obtain the water-soluble and alcohol-soluble active ingredients. Easy to keep.
- Alcoholic extracts. The dry or fresh vegetable part is macerated in alcohol to extract the alcohol-soluble principles. They are less effective than mother tincture. These include enoliths, preparations in which the extraction takes place using wine as a solvent.
- Dyes. Obtained by hydro-alcoholic maceration of the fresh plant, suitable for extracting the water-soluble and alcohol-soluble properties. The mother tincture is an extract in which the drug-solvent ratio is 1:10, but there is also the classic, less used tincture, in which the drug-solvent ratio is 1: 2
- Oleolites. They are obtained from the maceration in oil of the dry aerial parts of the plants. They are a type of extracts useful for obtaining the fat-soluble properties of the vegetable and have an application in cosmetics and phytotherapy. The plant is immersed for several weeks in vegetable oil chosen from among those that hardly go rancid.
- Extracts by grinding. With this technique, fresh plants are ground just after harvest, using different tools (such as mortars) to obtain a homogeneous pulp from which to obtain the pulp or juice.
- Extracted with water and heat. They use water and heat starting from water-soluble and non-thermolabile herbs to obtain preparations such as herbal teas, infusions and decoctions. The difference lies in the different infusion times, the type and quantity of herbal drugs, as well as the use that can be made of them (internal or external).
- Essential oils. Obtained by steam distillation of the fresh plant or by its cold pressure, they are the true ‘essence’ of the plant. They are suitable for extracting the active ingredients soluble in vapor or thermolabile in a very concentrated way. They are mainly used in aromatherapy and perfumery.
- Hydrolates. They are extracted from the vegetable by steam distillation and are the lightest residual part composed of the greatest amount of water and less oil that remains in the distiller. They contain water-soluble active ingredients.
- Vegetable oils, butters and waxes. Produced by pressing or squeezing the most oily and hardest parts of the plant, usually seeds and roots. They are rich in fatty acids and have an unsaponifiable part which determines their aromatic and flavor characteristics.
- Concrete and absolute. From the extraction with supercritical CO2 or other volatile solvent, a high concentration of oils and the other most valuable active ingredients of the plant is obtained. Not suitable for all plants. It is mainly used in the perfume industry due to the high cost.
Extraction of active ingredients with elimination of the solvent
The extracts obtained following maceration and distillation need to eliminate the solvent (water, alcohol, glycerol, oil) used, until the desired degree of concentration is obtained.
Based on the amount of solvent remaining in the preparation, extracts of different consistencies can be distinguished. In fact, we can speak of:
- Fluid extract: preparation obtained by macerating dried or fresh vegetable parts in a solvent that favors the extraction of the active ingredients. Liquid extracts in a hydroalcoholic mixture (about 30%) such as mother tincture, and glyceric and hydro-glycerine extracts belong to this category. Being water-soluble, the fluid extracts can be used in the formulation of emulsions, tonics, gels, lotions and detergents
- Dry extract: it is obtained by concentrating and drying the fluid extracts. This is the most concentrated type of extract.
- Soft extract: preparation with an intermediate consistency between fluid and dry extract. It is obtained by evaporation of the solvent (usually ethanol).
Extraction of active ingredients without elimination of the solvent
All the macerations in solvent that is not eliminated, with or without heat, are used for preparations with different active ingredients and different applications. Let’s see them better.
- Using water as a solvent and using heat, herbal teas, infusions, decoctions are obtained, which can be used for internal or external use, that is to drink or to make a local compress.
- By macerating parts of the dried plant only in water, but without heat, aqueous macerates are obtained which retain the active ingredients that dissolve in water and do not resist heat. They are useful for various therapeutic and cosmetic purposes, but have the drawback of not being preserved and difficult to extract. An example of aqueous macerate are psyllium seeds which contain mucilage effective for intestinal regularity which are activated thanks to water.
- By macerating in solvents other than water and without heat, different types of active ingredients are extracted, and as many preparations are obtained based on the solvent used. The most used solvents are alcohol, glycerol, ether, oil. Depending on the solvent, fresh or dried plant parts can be used. Maceration in solvent allows to obtain tinctures, mother tinctures, vinous tinctures, alcoholic macerates, hydroalcoholic macerates, glyceric macerates, bud derivatives and oleolites. All these preparations have in common a good conservation and a consistent active level.
Extraction from the aromatic parts of the plant
If you want to keep the aromatic part of the plant, then it is good to use the extraction by direct distillation or in a current of steam, but also pressing and cold pressing of the fresh plant or its cold pressure.
In this way essential oils and hydrolates are obtained.
They are a concentrate of active elements extracted from the most aromatic part of the fresh plant, and are obtained through various processes:
- cold pressing
- direct distillation or by steam current
Among the plant extracts, essential oils are the most powerful due to the high concentration of active ingredients. Also for this reason, these products must be used with great caution.
Important warning: essential oils must always be diluted and never be used alone!
Hydrolates or aromatic waters
Aromatic waters or hydrolates are the secondary product of the essential oil extraction process.
Definitely more delicate, they have a higher percentage of water that makes them ‘float’ on the actual essential oil, richer in oily parts.
They can also be used for external use, for example as face tonics and eye decongestants.
Extraction of the oily parts of the plant
The mechanical pressure at room temperature of the parts richest in lipids of the plant, generally its seeds and fruits, allows to obtain solid or liquid vegetable extracts such as oil, butter and vegetable wax rich in fatty acids.
For example cumin oil, cocoa butter, carnauba wax. These products are used in cosmetics and phytotherapy as well as in the food sector.
Why are plant extracts used a lot in cosmetics?
First of all because they contain functional properties for the skin. Specifically, plant extracts have properties:
Furthermore, the active ingredients processed through the extraction method retain their properties unaltered. The plant extracts therefore perform their specific function in the best possible way.
In practice, applying a cream rich in extracts to the skin is like spreading the pure liquid of the plant.
Moisturizers often contain extracts, because they guarantee a beneficial action on the skin and are very useful for maintaining skin health.
Each plant extract is effective for certain situations: some help sensitive skin, others regulate oily skin, and still others give brightness to dull skin.
Plant extracts in pharmacies and herbalists
The extracts are used to solve various ailments. also as a natural drug and as an ingredient in a galenic preparation made directly by the pharmacist.
What are the botanical extracts most used in face creams?
Here is a brief rundown of the most famous botanical extracts used in face creams.
- Aloe (Aloe barbadensis): gelatinous liquid contained in the central part of the leaves of Aloe vera. It is rich in vitamins, amino acids and minerals that are beneficial to the skin. Aloe extract is added to cosmetics for its soothing, moisturizing and anti-aging action
- Gotu kola (Centella asiatica Extract): gotu kola extract is inserted into creams by virtue of its restorative and regenerating action, as it stimulates the formation of new collagen. It also promotes skin tone, very useful in case of wrinkles and skin sagging
- Witch hazel (Hamamelis virginiana): witch hazel extract has calming and delicately astringent properties. Ideal for both soothing and purifying sensitive skin
- Moringa (Moringa oleifera Seed Extract): the moringa extract has an antioxidant action that keeps the skin young and healthy
- Chamomile (Chamomilla Recutita): has a predominantly calming and soothing action. Often present in specific creams against redness and couperose
- Green Tea (Camellia sensis extract): green tea extract has innumerable antioxidant virtues which, for the skin, translate into firmness, elasticity and vitality
- Licorice (Glycyrrhiza Glabra Root Extract): the licorice extract has a high anti-inflammatory power; for this reason it is often present in creams against skin imperfections, and also in the presence of acne
- Algae: thanks to their antioxidant and regenerating power, algae have an anti-aging action that helps the skin stay young. The main ones used in cosmetics are chlorella, spirulina and wakame
Food supplements based on plant extracts
Food supplements containing botanical extracts fall under food law. Their approval is based above all on the quality of the raw material and on safety, which must be guaranteed by the producer and along the entire supply chain, with the same quality controls required for all foods.
Specifically, those who grow the vegetable ingredient must apply the rules of Good Agricultural Practices (GAP). Who produces the integrator must follow the Good Production Practices, from the verification of the raw material to the guarantee of the final quality. And it must also verify the absence of biological or chemical contaminants.
The label must show the content of regulated molecules, also indicating the safe daily doses for the consumer.
Attention : only extracts approved for this use can be used.
Warnings and contraindications on supplements based on plant extracts
Finally, it should be remembered that, like any type of supplement, even those based on plant extracts are not intended as a substitute for a healthy, correct and balanced diet.
It is always a good idea to seek advice from the pharmacist or herbalist and, in case of therapy with traditional drugs, consult your doctor first.
Some plant-based supplements can in fact interact with some drugs, making them ineffective or even dangerous. For example, St. John’s wort can inhibit the activity of some drugs, licorice should not be taken by subjects being treated for high blood pressure, gingko should be avoided by those on anticoagulant or antiplatelet therapy, while valerian accentuates the action some sedatives.