Phytochemical investigation of the stems and leaves of Paris polyphyila var. yunnanensis led to isolation of 12 steroidal saponins, chonglouosides SL-9-SL-20, which had not been described previously, along with 13 known compounds. Their structures were established on the basis of extensive spectroscopic analysis and chemical methods. Four of the twelve steroidal saponins possessed three steroidal aglycones which have not been reported in nature. Steroidal saponins were also evaluated for their cytotoxicities against two human cancer cell lines (HepG2 and HEK293) and anti-HCV effects. One known steroidal saponin was the most cytotoxic compound overall with IC50 values of 2.9 +/- 0.5 mu M and 5.0 +/- 0.6 mu M against HepG2 and HEK293 cell lines, respectively, while none showed anti-HCV activity at a concentration of 20 mu M. (C) 2015 Elsevier Ltd. All rights reserved.