Minor furofurano lignans from the Tibetan herb, Lancea tibetica

Four new furofurano lignans, lantibesides B - D ( 1 - 3) and lantibetin ( 4), along with nine known phenolic compounds were isolated from the EtOH extract of the traditional Tibetan medicinal plant, Lancea tibetica. By means of spectroscopic and chemical methods, the structures of the new compounds were elucidated as (1 R,2 S,5 R,6 S)-2-(3,4-methylenedioxyphenyl)-6-[(3-methoxy-4-beta- D-xylopyranosyloxy(1-->6)-beta- D-glucopyranosyloxy)phenyl]-3,7-dioxabicyclo[3.3.0]octane ( 1), (1 R,2 R,5 R,6 S)-2-(3,4-methylenedioxyphenyl)-6-[(3-methoxy-4-beta- D-xylopyranosyloxy(1-->6)-beta- D-glucopyranosyloxy)phenyl]-3,7-dioxabicyclo [3.3.0]octane ( 2), (1 R,2 R,5 R,6 S)-2-(3,4-methylenedioxyphenyl)-6-(3-methoxy-4-beta- D-glucopyranosyloxy)phenyl-3,7-dioxabicyclo[3.3.0]octane ( 3), and (1 R,2 R,5 R,6 S)-2-(3,4-dimethoxyphenyl)-6-(3,4-dihydroxyphenyl)-3,7-dioxabicyclo[3.3.0] octane ( 4). Compounds 2 and 3 showed weak cytotoxicity against the HL-60 cell line with IC (50) values of 61 and 99 microM, respectively.