Complete H-1 and C-13 NMR assignment and P-31 NMR determination of pentacyclic triterpenic acids

摘要

In this study we report the complete and unambiguous H-1 and C-13 NMR assignment of betulinic, maslinic, oleanolic and ursolic acids by utilizing high-resolution multidimensional NMR spectroscopy. In addition, we developed a P-31 NMR methodology for the qualitative and quantitative analysis of these triterpenic acids. The P-31 NMR methodology was validated using standard solutions of model compounds and has excellent accuracy and repeatability. NMR spectroscopy was proved to be a powerful tool for the determination of these bioactive molecules and will be an important aid for scientists who will perform interaction studies with these compounds, as well as researchers who need to determine and quantify them at their native sources.