Abstract
A new lignan glycoside, 7α, 7′β-bis-(4-hydroxy-3-methoxyphenyl)-7,9′:7′,9-diepoxylignan-8αH,8′α-O-β-d-(2″,7′α-epoxy)-glucopyranoside, named elshrugulosain (1), has been isolated from the EtOH extract of Elsholtzia rugulosa, together with six known compounds, ( − )-bornyl (E)-3,4,5-trimethoxycinnamate, apigenin, luteolin, apigenin-7-O-β-d-glucopyranoside, luteolin-7-O-β-d-glucopyranoside, and luteolin-3′-glucuronate methyl ester. Their structures were characterized by spectroscopic methods and comparison with the data in the literature. On the basis of detailed 1D and 2D NMR spectral analysis, as well as X-ray crystallographic diffraction, the NMR spectroscopic data of ( − )-bornyl (E)-3,4,5-trimethoxycinnamate were revised and assigned completely.
Acknowledgements
We would like to thank Prof. Y. Lv of the Department of Instrumental Analysis, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College for single-crystal X-ray diffraction analysis. This work was supported by grants from the National Science and Technology Project of China (No. 2011ZX09307-002-01).