Flavonoids from (Oleaceae) Flowers and Their Protective Effects against Glutamate-Induced Cell Toxicity in HT22 Cells.

The dried flowers of were extracted with 80% MeOH, and the concentrate was divided into EtOAc, -BuOH, and HO fractions. Repeated SiO, octadecyl SiO (ODS), and Sephadex LH-20 column chromatography of the EtOAc fraction led to the isolation of four flavonols (-), three flavones (-), four flavanonols (-), and one flavanone (), which were identified based on extensive analysis of various spectroscopic data. Flavonoids - and - were isolated from the flowers of for the first time in this study. Flavonoids , , , , , and - significantly inhibited NO production in RAW 264.7 cells stimulated by lipopolysaccharide (LPS) and glutamate-induced cell toxicity and effectively increased HO-1 protein expression in mouse hippocampal HT22 cells. Flavonoids with significant neuroprotective activity were also found to recover oxidative-stress-induced cell damage by increasing HO-1 protein expression. This article demonstrates that flavonoids from flowers have significant potential as therapeutic materials in inflammation and neurodisease.