Extraction Methods

It is a method of extraction where the whole or coarsely powdered crude drug is placed in a stoppered container with the solvent and allowed to stand at room temperature for a period of at least 3 days with frequent agitation until the soluble matter has dissolved. The mixture then is strained, the marc (the damp solid material) is pressed, and the combined liquids are clarified by filtration or decantation after standing.

• Maceration

• Infusion

• Digestion

• Decoction

It is a method of extraction where there is continuous downward displacement of the solvent through the bed of crude drug material to get extract. It is frequently used to extract active ingredients in the preparation of tinctures and fluid extracts.

• Maceration

• Percolation

• Digestion

• Decoction

It is a method of extraction of chemical compounds or flavors from a plant material in a solvent such as water, oil or alcohol, by allowing the material to remain suspended in the solvent overtime.

• Maceration

• Percolation

• Infusion

• Decoction

It is a method of extraction where the crude drug is boiled in a specified volume of water for a defined time. It is then cooled and strained or filtered. This procedure is suitable for extracting water-soluble, heat stable constituents.

• Maceration

• Percolation

• Infusion

• Decoction

In this extraction method, a small amount of dry sample is placed in a thimble, which is placed in a distillation flask containing the solvent of particular interest. After reaching an overflow level, the solution of the thimble-holder is aspirated by a siphon, which unloads the solution back into the distillation flask. This solution carries the extracted solutes into the bulk liquid. The solute remains behind in the distillation flask, and the solvent passes back to the solid bed of samples. The process is repeated until complete extraction takes place.

• Maceration

• Percolation

• Infusion

• Soxhlet Extraction

In this extraction method, the drug is extracted by heating a particular pressure. This will increase the penetration power of the menstruum so that there is complete extraction of the drug. Precautions must be taken so that the increase temperature may not harm the constituents of the drug.

• Maceration

• Percolation

• Soxhlet Extraction

• Digestion

This method of extraction applies high pressure in extraction. High pressure keeps solvents in a liquid state above their boiling point resulting in a high solubility and high diffusion rate of lipid solutes in the solvent, and a high penetration of the solvent in the matrix. This dramatically decreased the consumption of extraction time and solvent and had better repeatability compared to other methods.

• Maceration

• Percolation

• Soxhlet Extraction

• Pressurized Liquid Extraction

This method requires less extraction time and solvent. It cannot be used for the extraction of thermolabile natural products. Refluxing with 70% ethanol provided the highest yield of the natural bio-insecticidal, didehydrostemofoline, (0.515% w/w of the extract), from Stemona collinsiae root among the extracts prepared by different extraction methods. This method was found to be better than the decoction method and the highest yields of baicalin and puerarin were obtained from the reflux method with 60% ethanol as the extraction solvent.

• Reflux Extraction

• Percolation

• Soxhlet Extraction

• Pressurized Liquid Extraction