LC-MS guided isolation of (±)-sweriledugenin A, a pair of enantiomeric lactones, from Swertia leducii.

(±)-Sweriledugenin A, a pair of novel enantiomeric lactones, were isolated from Swertia leducii under the guidance of LC-MS investigation. The enantiomeric separation was achieved by HPLC on a chiral column. Their structures were determined by extensive NMR spectra, X-ray, and quantum calculations. (+)-Sweriledugenin A and (-)-sweriledugenin A showed activities inhibiting HBV DNA replication with the IC50 values of 36.86 and 26.55 μM on the HepG 2.2.15 cell line in vitro.