Neurotherapy of Yi-Gan-San, a Traditional Herbal Medicine, in an Alzheimer's Disease Model of Drosophila melanogaster by Alleviating Aβ42 Expression

Alzheimer's disease (AD), a main cause of dementia, is the most common neurodegenerative disease that is related to the abnormal accumulation of amyloid beta (A beta) proteins. Yi-Gan-San (YGS), a traditional herbal medicine, has been used for the management of neurodegenerative disorders and for the treatment of neurosis, insomnia and dementia. The aim of this study was to examine antioxidant capacity and cytotoxicity of YGS treatment by using 2,2-Diphenyl-1-picrylhydrazyl (DPPH) and 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays in vitro. We explored neuroprotective effects of YGS treatment in alleviating A beta neurotoxicity of Drosophila melanogaster in vivo by comparing survival rate, climbing index, and A beta expressions through retinal green fluorescent protein (GFP) expression, highly sensitive immunomagnetic reduction (IMR) and Western blotting assays. In the in vitro study, our results showed that scavenging activities of free radical and SH-SY5Y nerve cell viability were increased significantly (p < 0.01-0.05). In the in vivo study, A beta(42)-expressing flies (A beta(42)-GFP flies) and their WT flies (mCD8-GFP flies) were used as an animal model to examine the neurotherapeutic effects of YGS treatment. Our results showed that, in comparison with those A beta(42) flies under sham treatments, A beta(42) flies under YGS treatments showed a greater survival rate, better climbing speed, and lower A beta(42) aggregation in Drosophila brain tissue (p < 0.01). Our findings suggest that YGS should have a beneficial alternative therapy for AD and dementia via alleviating A beta neurotoxicity in the brain tissue.

Automated summary

The study aimed to investigate the therapeutic effects of Yi-Gan-San (YGS) on Alzheimer's disease (AD) and dementia. The results showed that YGS exhibited antioxidant capacity and improved nerve cell viability in vitro. In vivo, YGS alleviated Aβ protein aggregation, increased survival rate, and improved motor abilities in Drosophila flies.