Normally we use different solvent to extract different organic constituents like Pet, ether, CHCl3, MeOH etc., then CC, then TLC, then PTLC etc.
However, I want to purify flavonoids only. Can you give advice?
If you mean phenolic compounds, I use strong anion exchange (SAX) columns. This has the advantage of removing basic and neutral compounds from the extract so you only have acidic compounds left.
Please see: http://www.isco.com/WebProductFiles/Applications/101/Poster_and_Paper_Reprints/Purification_of_Phenolic_Flavonoids.pdf
Another potential method is the use of a polyamide column. This can also be run after the ion exchange I mention above.
Run a gradient starting with water to 100% methanol, another gradient from methanol to 100% acetone, then acetone to 100% water containing 5% ammonium hydroxide (3 gradients total). The 3 gradients elute different compounds.
Routray, W., Orsat, V. 2013. Preparative extraction and separation of phenolic compounds. In Ramawat, K.G., Merillon, J.-M. (Ed.), Natural Products: Phytochemistry, botany and metabolism of alkaloids, phenolics and terpenes. Springer-Verlag Berlin, Heidelberg.
If you mean phenolic compounds, I use strong anion exchange (SAX) columns. This has the advantage of removing basic and neutral compounds from the extract so you only have acidic compounds left.
Please see: http://www.isco.com/WebProductFiles/Applications/101/Poster_and_Paper_Reprints/Purification_of_Phenolic_Flavonoids.pdf
Another potential method is the use of a polyamide column. This can also be run after the ion exchange I mention above.
Run a gradient starting with water to 100% methanol, another gradient from methanol to 100% acetone, then acetone to 100% water containing 5% ammonium hydroxide (3 gradients total). The 3 gradients elute different compounds.
Dear Islam
Check the following thread and publications.
https://www.researchgate.net/post/what_is_the_best_solvent_system_for_isolation_of_terpenoids_and_flavonoids
Try with a Amberlite XAD-7 resin. These type of resin enriches your extract in phenolic compounds, anthocyanins flavonoids, etc.
LH 20 retains phenolic compounds including flavonids, but the resin get coloured. To try to recover, after chromatogrphy you can wash the resin with HCl 1-5%. and then wahs with water until pH 7
Isolation/purification etc depends on what is the purpose of the substance you want. For instance, if you want to treat cells with your isolate, then it should not contain methanol or organic solvents as these will become contaminants and interfere with the results. For such purposes, it may be advisable to find centrifugal methods and then determine the fraction that contains flavinoids.
Check this useful and informative link:
http://www.slideshare.net/rahulbs89/extraction-of-plant-contituents
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