Terpene and phenolic constituents of Lactuca indica L.

We isolated seven terpenes and five phenolic constituents from the aerial parts of Lactuca indica L. using column chromatographic separation of its MeOH extract. Their structures were determined by spectroscopic methods to be trans-phytol (1), 3beta-hydroxyglutin-5-ene (2), 5,6-epoxy-3-hydroxy-7-megastigmen-9-one (3), 11beta-13-dihydrolactucin (4), 2-phenylethyl beta-D-glucopyranoside (5), cichorioside B (6), 1-hydroxylinaloyl-6-O-beta-D-glucopyranoside (7), (6S,9S)-roseoside (8), benzyl-beta-D-glucopyranoside (9), 2-(3'-O-beta-D-glucopyranosyl-4'-hydroxyphenyl)-ethanol (10), 3-(beta-D-glucopyranosyloxymethyl)-2-(4-hydroxy-3-methoxyphenyl)-5-(3-hydroxypropyl)-7-methoxy-dihydrobenzofuran (11), and (+)-taraxafolin-B (12). Compounds 1-3, 5, and 7-12 were isolated for the first time from this plant source. The isolated compounds were tested for cytotoxicity against four human tumor cell lines in vitro using a Sulforhodamin B bioassay.