Methods Used In Extraction
Pre-Stage Of Extraction
First step of any plant extraction process is to preserve the bio-molecules of plant for best results. For this purpose we can use plant material dried, fresh, grinded or powdered form. Our end quality also depends more or less on the method of preserving the plant parts. In case of licorice there is no significant difference in results either we use fresh or dried sample nut over drying must be avoided. Similarly we can use powdered and grinded form licorice root for extraction but it is better to use grinded form as it will give it more surface area to intact with the extraction solvent. Following four methods are mainly used for extracting the licorice from roots of “Glycyrrhiza glabra”.
Extraction Methods
Extraction means to separate the medicinally active components of plant from its parent source using best available procedures. In case of licorice we can use any of the following methods. Each method has its own advantages and disadvantages. Lets have a look at them in the following tabs.
Analytical method mainly comprises of extraction of the principle
component glycyrrhizin from the licorice roots with following key points:-
- We use combination of all the three individual analytical extraction methods i.e acid
precipitation, alcohol and ammonia extraction - Starts with heating of the shredded roots of licorice for 4 to 6 hours in ten
times its volume of distilled water at 60°C at a neutral pH - Suspension is centrifuged, and the supernatant is evaporated in
vacuum to about 75% of its volume. - Crude glycyrrhizic acid is then precipitated by addition of 10% concentrated sulphuric acid (H2SO4) at
constant stirring. - Нis crude powder is taken up in fresh distilled water and stirred for 4 to 6 hours to bring the pH at 4 by using NH4OH/sodium carbonate/potassium carbonate.
- Stirring is continued followed by centrifugation till a clear supernatant is obtained. Similar washing
steps are continued with fresh distilled water to neutralize the pH of the precipitate. - Finally, the crude is completely dried and extracted in absolute ethanol which is further evaporated on water bath and dried in vacuum oven to obtain active glycyrrhizic acid.
- Нe recovery of active glycyrrhizic acid by analytical method is 7-8% only
- Microwave energy is used to facilitate the breaking of analytes from the sample matrix into the extraction solvent.
- Microwave radiation interacts with the dipoles of the polar and polarizable materials in the solvent and the sample causing heating
- This heat is transferred through conduction promoting solvent penetration into the sample thereby enhancing migration of the active
constituents into the extraction solvent
- This method involves use of ultrasound using a sonicator probe ranging from 20 kHz to 2000 kHz
- Нe vibrational and acoustic eوٴect from the ultrasound increases the surface contact between the
solvent and samples thereby increasing the permeability of the plant cell walls. - The physical and chemical properties of the plant cell wall is disrupted and altered which results in the mass transportation
of the solvent into the plant cell. - It facilitates release of the active constituent in the desired solvent of extraction
- Maceration or dipping method involves soaking plant materials (coarse or powdered) in a stoppered container with a desired solvent
and allowed to stand in the room temperature for a period of time. - Нis process intends to break the cell wall of plant cells to release the desired phytochemicals in the extraction solvent being used.
- Нe choice of solvent used will determine the type of compound extracted from the samples, basically playing the most critical role.
- The root extract was dipped in this extraction solvent for about 60 mins. so that the glycyrrhizic acid gets
dissolved in the solvent. - In case of licorice roots, the solvent used was ethanol and water for 10gm of licorice root extract.