Cytoprotective constituents of the heartwood of caesalpinia sappan on glutamate-induced oxidative damage in ht22 cells

The bioassay-guided fractionation of a MeOH extract of the heartwood of Caesalpinia sappan L. provided two neuroprotective compounds, sappanchalcone (2) and 4-0-methylepisappanol (3), together with a methoxychalcone, isoliquiritigenin 2'-methyl ether (1), and three aromatic compounds, 4-0-methylsappanol (4), caesalpine J (5), pluchoic acid (6). At concentrations of 20-40 /im, compound 2 showed significant cytoprotective effects against glutamate-induced oxidative stress through the induction of heme oxygenase (HO)-1 in HT22- immortalized hippocampal cells. Compound 3 also showed moderate neuroprotective effect at 40 //m, but compounds 1, 4-6 did not show any protective effects against glutamate-induced cytotoxicity in HT22 cells.