Balsacones D-I, dihydrocinnamoyl flavans from Populus balsamifera buds.

A phytochemical investigation of an ethanolic extract from Populus balsamifera L. buds resulted in the isolation and characterization of twelve new flavan derivatives consisting of six pairs of enantiomers. Structures of (+) and (-)-balsacones D-I were elucidated based on spectroscopic data (1D and 2D NMR, MS) and their absolute configurations were established using X-ray single crystal diffraction analysis and ECD computational calculations. Antibacterial activity and cytotoxicity of all purified enantiomers were evaluated in vitro against Staphylococcus aureus and human skin fibroblast cells, respectively. Crown