Clarke, DavidAlIbrahim, Fatimah2024-10-152024https://hdl.handle.net/20.500.14154/73242The dissertation discusses the analysis of various bark extracts using UPLC-MS/MS to accurately quantify three specific flavonoids and relate the quantitation data with their known biological activity.Drug resistance poses a rising problem for the control of helminth infections in animals, and recently research efforts have highlighted secondary plant metabolites, such as flavonoids, as promising compounds with anti-parasitic activity.1-4 However, accurately quantifying metabolites in complex plant matrices remains challenging. This project addresses this challenge by developing a sensitive analytical method to quantify three flavonoids; taxifolin, quercetin, and luteolin in bark extracts using ultra high-performance liquid chromatography coupled with tandem mass spectrometry (UPLC-MS/MS). The three analytes were separated on a BEH C18 column (2.1mm ×100mm × 1.7µm) using a gradient elution with a mobile phase of water and acetonitrile in 0.1% formic acid. Ion pair monitoring in negative ESI mode using the SRM method was successfully developed for each metabolite. The calibration curve of taxifolin demonstrated excellent linearity over the concentration range of 2-50 µM with a correlation coefficient of 0.99949. Quercetin and luteolin did not demonstrate reliable calibration curves nor were they detected in any bark extracts. Taxifolin was analysed in ten bark samples and four samples were above the level of quantitation. In future work, the quantitation of secondary metabolites in bark samples will be correlated to biological activity to identify possible cost-effective natural anti-parasitic additives for animal feed.40enAnalytical ChemistryChemistryLC-MS/MSFlavonoidsThesis