Hi Sivakumar,

In order to separate any compound, you should give more information about the bioassay target and the fraction that you are going to purify viz. hexane, DCM or MeOH

regards

I'm assuming natural products here.  Read the Journal of Natural Products for some general information. However, you'll find out how they  purified the various compounds, and not the steps they followed to figure out that purification procedure.

Do a literature search on the genus and species that you extracted so you can see what compounds have already been discovered. Likewise, do a literature search on the bioassay that you will be testing for activity, since you may find a particular class of compounds tend to show activity for a particular biology, and you can see how this class of compounds were purified.

In natural products, the problem is that we know a compound is active, but we don't know what compound in the extract causes the bioactivity. If you do assay-directed fractionation, I've come up with a column screen that allows one to find which columns may work, and provide information on usable solvent systems. See: http://www.isco.com/WebProductFiles/Applications/101/Poster_and_Paper_Reprints/New_Techniques_In_Extraction_Column_Screening.pdf

http://www.isco.com/WebProductFiles/Applications/101/Poster_and_Paper_Reprints/New_Techniques_in_Extract_Column_Screening_II.pdf

it depends what kind of components you want to extract. Normally, aqueous solution of methanol or ethanol in various concentrations is applied at 70-80 C fro 1-5 hours. if you need saponins, you can extract with 30% ethaol.

 I think you should conduct a thorough literature review for the said drug or its bioactive compounds and see the extraction methods used for the drug and select the appropriate method.The method of extraction will actually depend on the nature of the bioactive compound to be extracted.

I agree with the opinion of Jack

I agree with all the above scientists, go through the literature thoroughly related to the compound of your interest.