10th U6+ Consortium of African Universities International Conference

Lobostemon fruticosus (L.) H. Buek is an indigenous medicinal shrub widely used in traditional medicine in South Africa. This study investigated the phytochemical diversity and chemotypic variation of wild L. fruticosus populations collected from Rhodes Memorial, Doringrivier, and Grootnek fontein in the Western Cape Province. Leaf extracts were analysed using ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS), while chemometric analyses including PCA, PLS-DA, and OPLS-DA evaluated metabolite variation among populations. Among the eighteen compounds tentatively identified, Doringrivier samples contained high concentrations of rutin (5.142 mg/g), kaempferol (3.846 mg/g), and rosmarinic acid (0.069 mg/g), while Rhodes Memorial samples showed elevated levels of cirsimaritin (0.095 mg/g), sagerinic acid (0.182 mg/g), and lirioresinol A (0.144 mg/g). Grootnek fontein samples accumulated higher concentrations of pyrrolizidine alkaloids, particularly lycopsamine-N-oxide (3.899 mg/g). Multivariate analyses demonstrated clear chemotypic separation among populations, with PCA and PLS-DA explaining 97.2% of total variance. Statistical analysis identified lycopsamine-N-oxide, rutin, lycopsamine, globoidnan B, and rabdosiin as key discriminatory metabolites. Doringrivier was the most promising population for future medicinal cultivation due to its high concentration of beneficial phenolic compounds and lower pyrrolizidine alkaloids. This study contributes valuable information on the phytochemical characterization, quality standardization and medicinal potential of L. fruticosus.