Norlignans and phenylpropanoids from Metasequoia glyptostroboides Hu et Cheng

Five new compounds, i.e., the three new norlignans metasequirins GI (13) and the two new phenylpropanoids 7-(3-ethoxy-5-methoxyphenyl)propane-7,8,9-triol (=1-(3-ethoxy-5-methoxyphenyl)propane-1,2,3-triol; 4) and 7-(3-hydroxy-5-methoxyphenyl)propane-7,8,9-triol (=1-(3-hydroxy-5-methoxy-phenyl)propane-1,2,3-triol; 5), were isolated from the branches and stems of Metasequoia glyptostroboides Hu et Cheng. Their structures were elucidated by physical, chemical, and spectroscopic methods, including 1D- and 2D-NMR and HR-ESI-MS. The cytotoxicites of the five compounds were tested against A549 and Colo 205 cell lines by the MTT method.