Neuroprotective phenylethanoid glycosides with dioxane units from the fruits of Forsythia suspensa

Abstract

Six new phenylethanoid glycosides possessing dioxane moieties, named forsyoxasides A−F (1–6), together with four known such compounds (7–10) were isolated from the fruits of Forsythia suspensa. These structures were illustrated by extensive NMR spectroscopic techniques and by comparing their NMR data with the related literatures. Notably, forsyoxaside A (1) is a novel dioxane phenylethanoid glycoside with an axial aromatic ring, which is rare in the natural sources. Compounds 1, 4, 7 and 8 showed remarkable bioactivities against rotenone induced PC12 cell damage. Furthermore, 1 and 7 displayed strong activities against serum deprivation induced damage on the same cells.