Euonymus hamiltonianus Extract Improves Amnesia in APPswe/Tau Transgenic and Scopolamine-Induced Dementia Models

Abstract

Dementia is a syndrome exhibiting progressive impairments on cognition and behavior beyond the normal course of aging, and Alzheimer's disease (AD) is one of the neurodegenerative diseases known to cause dementia. We investigated the effect of KGC07EH, the 30% ethanol extract of Euonymus hamiltonianus, against amyloid-β (Aβ) production and cognitive dysfunction in dementia models. KGC07EH was treated on Hela cells expressing the Swedish mutant form of amyloid precursor protein (APP), and the AD triple transgenic (3× TG) mice were given KGC07EH orally during 11-14 months of age (100 and 300 mg/kg/day). SH-SY5Y cell line was used to test KGC07EH on scopolamine-induced elevation of acetylcholinesterase (AChE) activity. ICR mice were intraperitoneally injected with scopolamine, and KGC07EH was administered orally (50, 100, and 200 mg/kg/day) for 4 weeks. KGC07EH treatment decreased Aβ, sAPPβ-sw, and sAPPβ-wt levels and APP protein expressions while sAPPα was increased in Swedish mutant-transfected HeLa cells. KGC07EH treatment also significantly reduced the accumulation of Aβ plaques and tau tangles in the brain of 3× TG mice as well as improving the cognitive function. In SH-SY5Y cells cultured with scopolamine, KGC07EH dose-dependently attenuated the increase of AChE activity. KGC07EH also improved scopolamine-induced learning and memory impairment in scopolamine-injected mice, and in their cerebral cortex and hippocampus, the expression levels of p-ERK, p-CREB, p-Akt, and BDNF were attenuated. KGC07EH inhibits APP processing and Aβ production both in vitro and in vivo, while enhancing acetylcholine signaling and cognitive dysfunction which are the major symptoms of dementia.

Keywords: Euonymus hamiltonianus; Alzheimer’s disease; Amyloid beta; Dementia; Memory dysfunction.