A New Tetrahydrofuran Lignan Diglycoside from Viola tianshanica Maxim

A new lignan glycoside, tianshanoside A ( 1), together with a known phenylpropanoid glycoside, syringin ( 2) and two known lignan glycosides, picraquassioside C ( 3), and aketrilignoside B ( 4), were isolated from the whole plant of Viola tianshanica Maxim . The structure of the new compound was elucidated by extensive NMR ( 1H, 13C, COSY, HSQC, HMBC and ROESY) and high resolution mass spectrometry analysis. The three lignans 1, 3, and 4 did not exhibit significant cytotoxicity against human gastric cancer Ags cells or HepG2 liver cancer cells. This is the first report of the isolation of a lignan skeleton from the genus Viola L.