Effects of Flavonoid Compounds on β-amyloid-peptide-induced Neuronal Death in Cultured Mouse Cortical Neurons

다국어 초록 (Multilingual Abstract)

Excessive accumulation of β-amyloid peptide (Aβ) is one of the major mechanisms responsiblefor neuronal death in Alzheimer’s disease. Flavonoids, primarily antioxidants,are a group of polyphenolic compounds synthesized in plant cells. The presentstudy aimed to identify flavonoid compounds that could inhibit Aβ-induced neuronaldeath by examining the effects of various flavonoids on the neurotoxicity of Aβ fragment25-35 (Aβ25-35) in mouse cortical cultures. Aβ25-35 induced concentration- and exposure-time-dependent neuronal death. Neuronal death induced by 20 μM Aβ25-35 wassignificantly inhibited by treatment with either Trolox or ascorbic acid. Among 10 flavonoidcompounds tested [apigenin, baicalein, catechin, epicatechin, epigallocatechingallate (EGCG), kaempferol, luteolin, myricetin, quercetin, and rutin], all except apigeninshowed strong 1,1-diphenyl-2-pycrylhydrazyl (DPPH) scavenging activity undercell-free conditions. The flavonoid compounds except apigenin at a concentration of 30μM also significantly inhibited neuronal death induced by 20 μM Aβ25-35 at the end of24 hours of exposure. Epicatechin, EGCG, luteolin, and myricetin showed more potentand persistent neuroprotective action than did the other compounds. These resultsdemonstrated that oxidative stress was involved in Aβ-induced neuronal death, andantioxidative flavonoid compounds, especially epicatechin, EGCG, luteolin, and myricetin,could inhibit neuronal death. These findings suggest that these four compoundsmay be developed as neuroprotective agents against Alzheimer’s disease.

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