Assessing Bioactivity

In this month’s issue of Pharmacognosy Research, I would like to concentrate on the methodologies that are employed to assess the nature of the bioactivities of plant extracts. In vivo and / or in vitro test models, together with the structural determination of the chief components, are of course the gold standard in determining the active constituents. Despite the development of very rapid and sophisticated analytical techniques, for example, Liquid chromatography (LC) and Gas chromatography (GC) hyphenated with Mass Spectrometry (MS) and elaborate one and two-dimensional Nuclear Magnetic Resonance (NMR) techniques, the bioassay remains indispensable. In general, bioassays examine the response of a whole animal, an isolated tissue / cell line or an organism, to a given extract (or drug, chemical or pollutant) in order to evaluate the bioactivity or toxicity or both. Paradoxically the difference between a ‘cure’ and a ‘poison’ is quantity. Scientists must be able to determine the activity (biological mechanisms) and the identity of the plant-borne substances in order to extrapolate safe levels, dosage forms, and delivery modes, for human use. Read more...