Topic summary
Bioassay-guided fractionation

Extracted from the Wikipedia article Fractionation.
Bioassay-guided fractionation
A typical protocol to isolate a pure chemical agent from natural origin is step-by-step separation of extracted components based on differences in their bioassay-guided fractionation physicochemical properties, and assessing the biological activity, followed by next round of separation and assaying. Typically, such work is initiated after a given crude extract is deemed "active" in a particular in vitro assay.