THE DIFFERENT PLANT EXTRACTS
A guide to learn about the different types of natural plant extracts , how they are obtained, the type of active ingredients they contain and how they are used.
Plant assets and their solubility
Soluble or not soluble, that is the question ...
It is said that a substance (solid, liquid or gas) is soluble in a liquid (which will then be called the solvent ) when a certain amount of this substance dissolves in the liquid to form a homogeneous solution .
An oil soluble compound is said to be fat soluble and a water soluble compound is said to be water soluble .
A compound is generally soluble in a solvent with which it has chemical affinities : thus aromatic compounds, such as terpenes are said to be lipophilic (they have an affinity for oil), and they are liposoluble . Sugars, on the other hand, are hydrophilic compounds (have an affinity for water) and are water soluble .
With rare exceptions, a plant active ingredient is soluble in oil OR in water but cannot be soluble in oil AND in water . Many active ingredients are soluble in alcohol (ethanol) which is a very good solvent. The solubility of an active ingredient or an extract has an important role in:
- The extraction of the assets of the plant : to extract an active of a plant with a solvent (water, oil, alcohol, glycerin ... or hexane, propylene glycol ...), it is necessary that this asset is soluble in the chosen solvent . When preparing a plant extract, the choice of solvent is therefore essential and must depend on the solubility of the active agents that are to be extracted.
- The use of plant extracts : during the cosmetic formulation of an extract , it must be dissolved in a support in which it is soluble . Otherwise, it will have to be dispersed effectively. For example, in the case of essential oils, not soluble in water, it will be necessary to use a dispersant to incorporate them into an aqueous formula (lotion, gel).
When we talk about plants, the word "active" comes up very often, but what do we mean by "plant active" and what are the benefits of these active ingredients in cosmetics?
A plant active ingredient is a chemical compound naturally present in the plant , and which may have a certain “activity”, that is to say a certain effect on the skin , and therefore of interest in cosmetics.
Not all plants contain the same type of active ingredient, which is why we do not produce the same type of extract from all plants . So while it is easy to extract a Macadamia vegetable oil, there is no such thing as Macadamia essential oil.
The table below details, in a non-exhaustive way of course, the most common plant active ingredients , the type of plant in which they are found, their cosmetic properties, and the type of solvent in which they are soluble, which is decisive. both in the choice of their method of extraction and in their mode of use .