Bioassay-guided fractionation of the acid hydrolysate of total ginsenosides of Panax ginseng C.A. Meyer (Araliaceae) led to the isolation of a novel ginsengenin (1). The structure of 1 was determined as (20S,22S)-dammar-22,25-epoxy-3β,12β,20-triol by extensive spectroscopy and single-crystal X-ray diffraction analyses. The cytotoxicity of 1 was further tested against SW1116, HCT116, and A549 cells by the MTT method, with IC50 values in the range of 2.96-30.9 μmol/L.A novel aglycone (1) with an oxacyclopentane ring in the C-17 side chain was isolated from the acid hydrolysate of Panax ginseng. The new structure was elucidated based on spectroscopy and single-crystal X-ray diffraction analyses.

Neopanaxadiol (NPD), a new panaxadiol first obtained from the acid hydrolysate of the total ginsenosides of Panax ginseng C. A. Meyer (Araliaceae) in our laboratory, showed neuroprotective effect against glutamate-induced neurotoxicity in primary cultures of rat cortical cells (Tao et al. Chin Chem Lett 20:687–689, 2009). In this research, a sensitive and specifical method of ultra-performance liquid chromatography–electrospray mass spectrometry (UPLC-ESI-MS/MS) for the quantitative analysis of NPD in rat plasma was developed. The NPD and internal standard of panaxadiol were extracted from 200 μL of rat plasma samples with methanol, then the samples were injected in an UPLC (Waters BEH) with C18 column (50 mm × 2.1 mm i.d., 1.7 μm) and eluted with the mobile phase consisting of methanol–water–formic acid (80:20:0.2, v/v/v). Excellent linearity was found between 5 and 160 ng mL−1 with a limit of quantitation of 4 ng mL−1. Intra- and inter-day precision values (RSD) of QC samples were both below 7 %. This study was successfully utilized for the pharmacokinetic profiles of NPD in rats after oral administration and provided an experimental basis for the further pharmacology and clinical application of ginseng products.