New triterpene saponins from Phryna ortegioides.

Four new and three known oleanane-type saponins have been isolated from the methanolic extract of Phryna ortegioides , a monotypic and endemic taxon of Caryophyllaceae. The structures of the new compounds were determined as gypsogenic acid 28- O -β- d -glucopyranosyl-(1→2)- O -β- d -glucopyranosyl-(1→6)- O -β- d -glucopyranosyl ester ( 1 ), 3- O -α- l -arabinofuranosyl-gypsogenic acid 28- O -β- d -glucopyranosyl-(1→3)- O -[β- d -glucopyranosyl-(1→6)]- O -β- d -glucopyranosyl ester ( 2 ), 3- O -α- l -arabinofuranosyl-gypsogenic acid 28- O -β- d -glucopyranosyl-(1→3)- O -[β- d -glucopyranosyl-(1→2)- O -β- d -glucopyranosyl-(1→6)- O -]-β- d -glucopyranosyl ester ( 3 ), 3- O -α- l -arabinofuranosyl-16α-hydroxyolean-12-en-23,28-dioic acid-28- O -β- d -glucopyranosyl-(1→3)- O -[β- d -glucopyranosyl-(1→2)- O -β- d -glucopyranosyl-(1→6)]- O -β- d -glucopyranosyl ester ( 4 ). Their structures were established by a combination of one- and two-dimensional NMR techniques, and mass spectrometry. Noteworthy, none of isolated compounds possesses as aglycone moiety gypsogenin, considered a marker of Caryophyllaceae family. The cytotoxic activity of the isolated compounds was evaluated against three cancer cell lines including A549 (human lung adenocarcinoma), A375 (human melanoma) and DeFew (human B lymphoma) cells. Only compound 6 showed a weak activity against A375 and DeFew cell lines with IC 50 values of 77 and 52 μM, respectively. None of the other tested compounds, in a range of concentrations between 12.5 and 100 μM, caused a significant reduction of the cell number. [ABSTRACT FROM AUTHOR]