Evaluation of Samjunghwan, a traditional medicine, for neuroprotection against damage by amyloid-beta in rat cortical neurons

Aim of the studySamjunghwan (SJH) is a multi-herbal traditional medicine composed of Mori Fructus, Lycii Radicis Cortex, and Atractylodis Rhizoma Alba and it is clinically applied as an anti-aging agent in neurodegenerative disorders, to promote longevity. In the present study, we evaluated the neuroprotective effect of SJH in Alzheimer's disease induced by amyloid-beta (Abeta) and examined the related pathways.Materials and methodsTo evaluate the protective effect of SJH, we conducted thiazolyl blue tetrazolium bromide, lactate dehydrogenase, and MAP-2 staining assays of primary cultured rat cortical neurons stressed by Abeta25-35. To investigate the possible mechanism of action, we examined the Bcl-2/Bax expression ratio, mitochondrial membrane potential (ΔψM), cytochrome C release, and caspase-3 activation, focusing on the mitochondria-mediated apoptotic pathways.ResultsSJH at concentrations of 10 and 100 μg/ml provided significant protection of rat cortical neurons from Abeta25-35 neurotoxicity. At the maximum effective dose of 100 μg/ml, SJH significantly increased the anti-apoptotic protein (Bcl-2)/pro-apoptotic protein (Bax) ratio and inhibited ΔψM depolarization, cytosolic cytochrome C release, and caspase-3 activation.ConclusionSJH appears to provide neuroprotection against mitochondria-mediated apoptotic pathways in this Abeta25-35-induced Alzheimer's disease model.