I want to know the method which is applied for isolating chemical compounds from plant materials.
It really depends on the compound and it's chemical properties, and whether you know what compound your are purifying. If the compound is known, there is probably a published method by which it was previously purified that you can follow.
If it is an unknown, you will probably follow assay guided fractionation. Some people extract the plant material starting with hexane (or petroleum ether), and follow that with solvents of increasing polarity (ethyl acetate, ethanol, and water, for example). These extracts are then subjected to column chromatography.
Others extract into alcohol followed by column chromatography.
Look up you plant's species and genus in the literature as this will give you an idea of what compounds these plants produce.
It depend on your chemical compound orientation and it polarity also the method you'll use.
First thing what kind of product you are expecting?.. If it is random then go for GC-MS by preparing extract with different solvents.. And check what all compounds are present then relate them with literature …
Suppose you got some medicinal compound in gc result, then work on purification part.
It really depends on the compound and it's chemical properties, and whether you know what compound your are purifying. If the compound is known, there is probably a published method by which it was previously purified that you can follow.
If it is an unknown, you will probably follow assay guided fractionation. Some people extract the plant material starting with hexane (or petroleum ether), and follow that with solvents of increasing polarity (ethyl acetate, ethanol, and water, for example). These extracts are then subjected to column chromatography.
Others extract into alcohol followed by column chromatography.
Look up you plant's species and genus in the literature as this will give you an idea of what compounds these plants produce.
A plant is a complex biochemical factory which produces various secondary metabolites which are useful to humans as pharmacologically active ingredients. Many bioactives are present in plants. As Jack said before, it depends on the compound and the chemical properties of the compound. I will add it also depends on the activity you are looking for in the plant. Another thing, if the chemical nature of the compound is known, it will be a bit easy for you to isolate it depending on the solubility of the compound in certain solvents based on polarity. If you don't have any idea, using solvents in increasing order of polarity is the best option to find out and screen the various phytoconstituents present.
Correctly suggested by Jack, first you should perform a thorough literature search about the plant and get an idea of the reported phytoconstituents. Then you can proceed as suggested. Once you have got the path, you can follow the directions otherwise it will be just like an aimless study which will leave you confused in the end.
GUd lUck and regards
Please specify your question. Write the name of the plant and the chemical compound you want to isolate. To my mind different solvents and methods are there for isolation. I hope you will get better response if question is specific and more clear.
I agreed what Jalk Silver and Alok Nahate wrote , it is a save way to follow
After you have run the following extraction procedure, you can run a 10% B to 90% B generic gradient on your HPLC to determine the best possible run conditions. If you have any further questions, feel free to send me a direct message.
Extraction procedure:
The big choice the scientist will have to make is to homogenize in nonpolar organic or water miscible organic. This will ultimately determine whether NORMAL phase (used with nonpolar solvents) or REVERSED phase (used with aqueous or water miscible organic that has been diluted with water) sorbent is used for the extraction. The rest of the steps are manipulations to remove large particulates such as insoluble plant parts.
General protocol of pretreatment includes a sequence of steps:
1. Homogenize the sample in proper solvent – that is select the appropriate organic solvent and turn on the
blender.
2. Filter, centrifuge and/or sonicate sample
3. Collect the supernatant
4. Any additional organic separation. Collect appropriate phase. Evaporate (NP methods) or dilute with water
(RP methods) as needed.
5. Apply to the SPE tube.*
Broadly isolation of chemical compounds from medicinal plants or any botanical material involve steps like extraction, fractionation, chromatography, purification and finally characterization by physicochemical and spectroscopic techniques. However, these methods vary to a great extents depending on the plant material and target compound to be isolated. Precise procedural steps can also be decided based on the bioefficacy of the plant that gives some idea about the chemical make-up of the plants. Bioassay guided isolation of active plant chemicals is based this concept. In fact, plant produces various secondary metabolites as a part of their defense mechanism, which are pharmacologically active ingredients useful as medicine. Isolation of such compounds depends the properties of the compound. If the chemical nature of the compound is known, it will be to isolate it depending on the solubility of the compound in certain solvents based on polarity following further separation and purification processes.
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