A New Steroid Saponin from the Rhizomes of Paris polyphylla var. yunnanensis

Phytochemical investigation of the ethanol extract from the rhizomes of Paris polyphylla var. yunnanensis led to the isolation of three steroid saponins (1–3) and two triterpenoid saponins (4, 5). Among them, compound 1 is a new steroid saponin, and 3–5 were obtained for the first time from the genus Paris. Their structures were elucidated on the basis of extensive analyses of spectroscopic data including IR, UV, MS, and 1D and 2D NMR. All of these compounds were tested for their cytotoxic activities on human nasopharyngeal cancer cells (CNE) and antiviral activities against respiratory syncytial virus (RSV). Steroidal saponins 1 and 2 showed moderate effects on CNE cells, with IC50 values 32.56 and 33.10 μM, respectively.