Six new diarylheptanoids from the seeds of Alpinia blepharocalyx

Chromatographic separation of part of an EtOH extract of the seeds of Alpin ia blepharocalyx resulted in the isolation of six new (1-6) and two known ( 7, 8) diarylheptanoids together with 12 known compounds. The structures of the new compounds, including their absolute stereochemistry, were elucidate d by spectroscopic and chemical methods as (3S,5S)- (1) and (3S,5R)-3-hydro xy-5-methoxy-1-(4-hydroxyphenyl)-7-phenyl-6E-heptene (2), (3S,5S)- (3) and (3S,5R)-3-hydroxy-5-ethoxy-1-(4-hydroxyphenyl)-7-phenyl -6E-heptene (4), (3 S)-methoxy-1,7-bis( 4-hydroxyphenyl)-6E-hepten-5-one (5), and 1,7-bis(4-hyd roxyphenyl)-hepta-4E,6E-dien-3-one (6). Among the isolated compounds, 5, (3 S,5S)-3,5-dihydroxy-1,7-bis(4-hydroxyphenyl)heptane (8), 4 ' -hydroxy-5,6-d ehydrokawain (14), and/or phloroglucinol (20) showed significant antiprolif erative activity against murine colon 26-L5 carcinoma (ED50: 5, 5 2 muM; 81 12.8 muM; 14, 20.7 muM; 20, 26.4 muM) and human HT-1080 fibrosarcoma (ED50 : 5, 10 1 muM; 14, 20.1 muM; 20, 20.9 muM) cells.