Structural revision of two flavanonol glycosides from Smilax glabra.

The structures of two flavanonol glycosides isolated from Smilax glabra, named smitilbin and neosmitilbin, have been revised to isoastilbin and neoastilbin, respectively. The revised structures were determined based on intensive studies of chemical interconversion, NMR spectroscopy, and X-ray crystallographic analysis. The latest NMR data were also summarized.