Four new norlignan glycoside isomers from the twigs of Cephalotaxus oliveri Mast.

Four novel isomers of norlignan glycoside were isolated from Cephalotaxus oliveri Mast.. Their structures were elucidated as 3 S -4″- O - β - d -glucopyranosylnyasol 1 , 3 S -4′- O - β - d -glucopyranosylnyasol 2 , 3 S -4″- O - β - d -glucopyranosylhinokiresinol 3 , 3 S -4′- O - β - d -glucopyranosylhinokiresinol 4 by extensive spectroscopic methods including 1D and 2D NMR experiments ( 1 H, 13 C, DEPT, 1 H– 1 H COSY, HSQC, HMBC, ROESY) along with HR-ESIMS and comparison to literature data. Their absolute configurations were elucidated through CD spectra coupled with the quantum chemical CD calculations.