Technical Abstract: Crude extracts, separated fractions, groups of chemical substances, and individual compounds from natural sources are all evaluated stepwise while performing purifications in in-house bioassays. In a stepwise fashion proceeding from crude extracts to fractions and on to pure compounds, decisions are made regarding how best to proceed based on biological evaluation results at each step. In order to use this bioassay-guided approach, the bioassays bust not only be relatively quick but such bioassays must also be capable of quantitatively ranking activity on sub milligram quantities of material. Natural product purifications often require the ability to work with such small sample sizes for both chemical and biological evaluations.