Abstract: Three new anthraquinones were isolated from the 80% ethanol extract of Prismatomeris tetrandra by silica gel, MCI, ODS column chromatography and high performance preparative liquid chromatography (HPLC). The structures of the new compounds were identified by mass spectrometry, nuclear magnetic resonance and other spectroscopic methods as 6-hydroxy-1,2,3-trimethoxy-7-methylanthracene-9,10-dione (1), 6-(hydroxymethyl)-1,2,3-trimethoxyanthracene-9,10-dione (2) and 7-hydroxy-6-(hydroxymethyl)-1,2-dimethoxyanthracene-9,10-dione (3). Compounds 1, 2 and 3 showed protective effects against monosodium glutamate-induced damage in SH-SY5Y neuroblastoma cells, with the cell survival rates elevated 18.45%, 4.31%, and 7.65%, respectively.