Again, I'll reply here so everyone gets the information...
There is no "single: isolation procedure that works for all compounds. If the compound is known, follow the purification procedure for that compound. Otherwise, you'll have to do some screening to determine the best column to purify compounds.
you should look in the literature to see what sort of compounds have already been found in the plant you are extracting. There is a reasonable chance that one of these is providing the biological activity, and you can see how those were purified.
I run a "column screen". The following posters describe the screen I use: