NMR-guided isolation of undescribed triterpenoid saponins from Lysimachia atropurpurea L.

Phytochemical investigation on aerial parts of Lysimachia atropurpurea L. (Myrsinaceae), guided by NMR methods, resulted in the isolation and characterization of three previously undescribed triterpenoid saponins named stralysaponins A-C along with five known compounds. Their structures were elucidated by 1D and 2D NMR spectroscopy and HR-ESI-MS. Stralysaponins A-C were categorized into 13β-28-epoxyoleanane-type triterpenoid saponins, reaffirming their prevalent presence of this type in the Myrsinaceae family and the genus Lysimachia. The identified derivatives share a common four-unit branched sugar chain, with rhamnose as the terminal sugar linked at C-3 of the aglycone. The presence of triterpenoid saponins in L. atropurpurea is reported herein for the first time. This study enriched the chemical diversity of triterpenoid saponins of the genus Lysimachia. Additionally, it demonstrates the effectiveness of NMR-profiling in isolating previously undescribed triterpenoid saponins from Lysimachia spp.