Herbal extracts capture the medicinal/ therapeutic essence of the plants that they are made from, and make this available to use for either medicinal purposes or for skincare formulations.
Herbal extracts can be made from different parts of a plant including flowers, leaves, roots, bark etc.
Its very important to research the particular plant you want to use for making extracts thoroughly in order to determine what the chemical composition of that plant is, its solubility, in what part of the plant it can be found in significant levels, as well as the therapeutic qualities of the plant.
Herbal extracts can be made with either fresh or dry plant parts. During the extraction process the desired chemical constituent is expected to be transferred from the plant material to the surrounding solvent (menstruum). At the end of the extraction process the used plant material can be disposed of while the enriched menstruum can now undergo purification and be used for medicinal or therapeutic purposes.
Solvents used for extraction
Oils are used for making herbal extracts when the chemical of interest is only soluble in oil phase or lipophilic. In this case you will need to use an oil based liquid to perform the extraction e.g. the chemical compound beta carotene in carrots can only be extracted in a lipophilic medium as it is oil soluble.
Water, alcohol, apple cider vinegar as well as glycerin are other solvents that can be used if the chemical of interest is water soluble or hydrophilic. The only difference between extracts made from these solvents is shelf life of the extract made with them. While alcohol extracts can last for at least 1 year, glycerine and apple cider vinegar extract can only keep for about 6 months refrigerated while water extracts should not be kept for more than 1day.
Extracts can also be cooked (heated) or left at room temperature, while slowly and carefully heating can produce extracts in less than 24 hours, keeping at room temperature can only produce good quality extracts when left alone and daily agitated for between 2-4weeks. Also some solvents can’t be heated e.g. alcohol as it is flammable.
Fresh or dry plant material
Either fresh or dried plant material can be used for making extracts. Only difference being that in dried plant materials, the water has been removed and therefore more solvent will be needed to rehydrate the plant material.
Therefore the ratio of plant material to solvent in extraction for dry and fresh material differ.
Dry plant material extraction ratio is 1:5(plant to solvent ratio) while fresh plant extraction ratio is about 1:2..
In order to maintain consistency in your extracts its important to weigh out both your plant material and solvent each time you make an extract.
Below are some pictures of an extract I made recently..
At the end of the 4 weeks filter off and discard your used plant material and enjoy using your plant extract as active ingredients in your formulations.
Remember that when formulating with herbal extracts, there are different rules for using natural preservatives!. We will be discussing this in our next blog!