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Chromatographic Techniques for Extraction and Isolation of Natural Products

Chromatography is a widely used method for the separation of mixture of components. It involves two phases: stationary and mobile phase. Mobile phase containing the mixture of components runs through the stationary phase and the component gets separated based on its affinity to it.
The column chromatographic technique is one of the most widely used methods for the extraction and isolation of natural products. Considering its sensitivity, it is an extremely convenient purification method that is widely used for the separation of bioactive compounds.

There are standard procedures for extracting the medicinally active compounds obtained from the plant for further carrying out the analysis following the extraction of desired biochemical components from the plant materials for further separation and characterization. Herbal Extraction can be carried out by both conventional and modern methods; conventional methods make the use of organic solvents or water for carrying out the extraction process at atmospheric process while the modern methods operate at elevated pressures and temperatures. Solvent extraction is one of the most widely used techniques for extraction where the solvent penetrates into the solid matrix dissolving the solute in the solvent and then solute is diffused out of the solid matrix, ready for the collection. Modern extraction is always preferred over the conventional extraction as it takes less time and gives more extraction yield by consuming less organic solvent.

Isolation and purification is further carried out by Column Chromatography. Column chromatography is the most sought-after technique for separating the various components of plant extracts. The obtained components in pure form are further analyzed for their effective use. This is known as preparative chromatographic method where stationary phase is packed in a column and the mobile phase is allowed to run through it after loading the extracts on top of the stationary phase. The mobile phase carries the natural products to be separated and each compound is obtained at a different rate based on its affinity to the stationary and mobile phase. Separated compounds are then collected for further use.

Being the easiest and cheapest technique, Thin Layer Chromatography is used commonly to carry out the isolation of natural components. Here, less polar mobile phase is used with more polar stationary phase and this is referred to as normal phase chromatography.

Scale up Chromatography: The scale-up of a chromatographic separation is mainly based on the principle which follows a simple procedure where process parameters are scalable in a linear fashion and the process is scaled by increasing the column diameter while keeping the remaining parameters like bed height, the velocity, and the volumes of the different phases (measured in column volumes) constant.

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James Sais

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