3.3.3 High-Performance Liquid Chromatography (HPLC) Marker Quantification

High-performance liquid chromatography provides definitive quantitative determination of a specific marker compound's content within a plant extract,...

High-performance liquid chromatography provides definitive quantitative determination of a specific marker compound's content within a plant extract, typically employing a reversed-phase C18 column with an acetonitrile- or methanol-based mobile phase and ultraviolet detection at the marker compound's characteristic absorption maximum. Well-established examples include curcuminoid quantification in turmeric (typically 2–5% in the crude rhizome powder, standardised to at least 95% total curcuminoids in a concentrated extract), withanolide A quantification in Ashwagandha root, glycyrrhizin quantification in liquorice root — of particular importance given the WHO-recommended intake limit arising from glycyrrhizin's mineralocorticoid-like pseudoaldosteronism risk — and andrographolide quantification in Andrographis paniculata leaf. Every quantitative HPLC method applied to marker compound determination must be formally validated according to ICH Q2(R1) guidelines, addressing linearity, accuracy, precision, and the limits of detection and quantification, as elaborated further in Phase 5.