What is the Extraction of Medicinal Plants?
For many years, plants have been a staple in medicine. From poultices to balms, to pills plants helped and continue to help treat various ailments at any level. For example, think of the household remedies of drinking chamomile and valerian tea for relaxation or chewing candied ginger for a stomachache. Plants involve themselves in our daily lives and while now we have many types of medications, various ones still have plant sources at their roots. This is one of the reasons the extraction of medicinal plants is so important.
Medicinal extraction involves separating the medically important portions of a plant from the inert ones by using solvents in one of the many common extraction procedures. The solvent used in these standardized extraction procedures is termed the ‘menstruum’.
The result of standard extraction methods is impure liquids and powders for oral or external use. Standardized extraction methods are incredibly important because it contributes to the final quality of the herbal extract or drug.
Steps Regarding Extraction of Medicinal Plants
- Size reduction
General Methods of Extraction for Medicinal Plants
Maceration: Maceration involves using a solvent to soak the medicinal plant material at room temperature for at least three days. During that time, the mixture is stirred or shaken often until the soluble material dissolves. It is then strained, and the excess is pressed for additional liquid. Afterward, the liquid is filtered.
Infusion: An infusion is prepared by maceration. However, the infusion can occur over a shorter amount of time with either cold or boiling water. The resulting solution is dilute and easy to dissolve. In fact, if you’ve had herbal tea chances are you’ve had an infusion.
Digestion: Is a method that is considered another form of maceration. During digestion, gentle heat is used to bolster the efficiency of the solvent, or menstruum used. Often, the plant material used is powdered. This method is a good one for soluble plants.
There are many more types of extraction including decoction, which involves boiling, and percolation, which is the method used most often when preparing tinctures or fluid extracts. There is also Soxhlet, counter-current extraction, aqueous-alcoholic extraction via fermentation, and supercritical fluid extraction among many other methods to get medicinal plant extracts.
Tips for Selecting an Extraction Method
- Make sure the plant material you are extracting from is legitimate. Anything that is not the desired plant material should be removed to avoid contamination
- Use the proper part of the plant, be it roots, leaves, flowers, or stems. Alkaloids, for example, are often found in the roots of plants.
- In the interest of quality control, it is a good idea to note the age of the plant, place of collection, season of collection, and time of both collection and use. The soil can impact the acidity of collected plants. An instance of this can be seen in the production of violet syrup, which is usually a pleasant purple or deep blue until lemon juice is added. However, when the soil is acidic, the syrup may come out pink despite no lemon juice being added as a result of the flowers being pre-acidified.
- When grinding plant material, the method used should be noted, and the technique should preferably not create heat.