Echinocystic Acid Bidesmoside Saponins from O. Hoffm and Their Cytotoxic Activity against the CAL-27 Oral Squamous Carcinoma Cell Line.

This paper describes eight new triterpenoid saponins, including afzeliioside A (), four acetylated afzeliiosides as pairs of inseparable regioisomers, called afzeliiosides B/C () and D/E (), afzeliiosides F-H (), and a known impatiprin C (), which were isolated from the -BuOH fraction of the liana of . Their structures were established mainly by extensive spectroscopic analysis, including 1D and 2D NMR, HRFAB-MS, tandem ESI-MS/MS, and chemical methods, as well as a comparison of their spectral data with those of related compounds. All the isolates were screened for their cytotoxic activity against the CAL-27 oral squamous carcinoma cell line. Only compounds (EC = 36.0 μg/mL (32.7 μM)) exhibited moderate cytotoxic activity. This work presents the first chemical and biological investigation of and reports, for the first time, on the isolation of saponins in the genus .