Bioactivity-guided isolation of biphenanthrenes from Liparis nervosa.

Three new biphenanthrenes, Liparisphenanthrenes A-C (1-3), along with three known ones were obtained from the ethanolic extract of Liparis nervosa (Orchidaceae) by bioactivity-guided fractionation. Their structures were elucidated on the basis of extensive spectroscopic analysis. All the compounds obtained were tested in vitro for cytotoxic activities against stomach (HGC-27) and colon (HT-29) cancer cell lines. 1, 4 and 5 showed potent cytotoxicities to HGC-27 cell line with IC50 values of 8.21-9.95μmol/L, and 1 and 5 also exhibited potent cytotoxic activities to HT-29 cell line with IC50 values of 8.53-9.27μmol/L.