Two new phenolic compounds from the seeds of Machilus yunnanensis

Chemical constituents investigation on the seeds of Machilus yunnanensis led to two new phenolic compounds 8-O-acetyl-phenylethanoid-4-O--D-glucopyranoside (1) and (E)-2,3-bis(4-hydroxyphenyl)acrylaldehyde (2), together with 16 known compounds. Their structures were elucidated on the basis of spectroscopic data analysis (IR, MS, 1D, and 2D NMR). Meanwhile, compounds 1-3, 6-13, 17, and 18 were evaluated for vasorelaxant effects on the rat endothelium-intact thoracic aorta rings precontracted with phenylephrine (PE) or KCl. The bioassay results showed that compound 17 had significant vasorelaxant effect on the endothelium-intact thoracic aorta rings precontracted with KCl.