New Galloylated Flavanonols from the Australian Plant Glochidion sumatranum

作者：Yin Sheng; Sykes Melissa L; Davis Rohan A; Shelper Todd; Avery Vicky M; Camp David; Quinn Ronald J^*

来源：Planta Medica, 2010, 76(16): 1877-1881.

DOI：10.1055/s-0030-1250071

• Glochidion sumatranum
• Euphorbiaceae
• galloylated flavanonols
• structural isomer
• antibacterial activity

Bioassay-guided fractionation of the CH(2)Cl(2)/MeOH extract from the Australian plant Glochidion sumatranum resulted in the isolation of four new galloylated flavanonols, (2R,3R)-dihydromyricetin-4'-O-(3 ''-O-methyl)-gallate (1), (2R,3R)-dihydromyricetin-3'-O-(3 ''-O-methyl)-gallate (2), (2R,3R)-dihydromyricetin-4'-O-gallate (3), and (2R,3R)-dihydromyricetin-3'-O-gallate (4), along with the known compound, (2R,3R)-dihydromyricetin (5). The structures of 1-5 were determined by NMR and MS analysis and their absolute configuration was elucidated by comparison of the CD data with literature values. Compounds 1/2 and 3/4 are two pairs of structural isomers that were shown to interconvert by transesterification during NMR and LC-MS studies. This process involved the intramolecular migration of the galloyl moieties between C-3' and C-4' of the flavanonol skeleton. Compounds 1 and 3 were identified as the more stable isomers. Compounds 1, 3, and 5 showed weak activity against the gram-negative bacterium Pseudomonas aeruginosa and the gram-positive bacterium Staphylococcus aureus.

• 出版日期2010-11