Protective Effects Of Ethanol Extract From Lithocpus Polystachyus Rehd On SH-SY5Y Cells And AD Model Nematodes

Lithocpus polystachyus Rehd,commonly known as sweet tea,is rich in natural bioactive substances,especially flavonoids,which have been reported to have a variety of health benefits such as antioxidant,anti-inflammatory,heart protection,liver protection,anti-diabetes and anti-cancer.Alzheimer’s disease(AD),also known as dementia,is a neurodegenerative disease.It has a high incidence among older people worldwide.So far,the pathogenesis of AD has not been clarified.The destruction of cell membranes by aggregates of misfolded proteins leading to neuronal apoptosis is an important hypothesized mechanism leading to AD.In this study,SH-SY5Y cells and AD model nematodes were used as models and the protective effect of sweet tea ethanol extract(ST)to Amyloid βprotein(Aβ)-induced SH-SY5Y cells and AD model nematodes were investigated.The main research contents of this paper are as follows:(1)Preparation and analysis of ST.The ethanol extract of sweet tea was extracted by rotary evaporation method using 80%ethanol as solvent.The total flavonoids content was 60.68±0.72 mg/g.By being analyzed with ultra-performance liquid chromatography,mass spectrometry,pharmacokinetics and molecular butt analysis,the main active components of ST were hydroxanthin,oxacin,hydrangea phenol,rhododendron and baicalin,etc..The effects of antioxidant stress,inhibition of Aβ aggregation and Tau hyperphosphorylation were mainly performed through PI3K/AKT signaling pathway,MAPK signaling pathway,Alzheimer’s disease and cell apoptosis pathway.(2)The protective effect of ST on SH-SY5 Y cells showed that,150μg/mL ST increased the Aβ treated SH-SY5Y cell viability from 55.84%to 89.3%.And ST could inhibite intracellular ROS production,decrease intracellular MDA content,and increase intracellular SOD and GSH content in the Aβ treated SH-SY5Y cells.St also could down-regulated the expression of Caspase-3,Caspase-9 and PARP proteins in SH-SY5Y cells,affecte the expression of AKT and MAPK signaling pathway related proteins,Tau protein phosphorylation and BACE1 protein expression in Aβ treated SH-SY5Y cells.ThT experiment showed that ST had certain inhibitory effect on Aβ(1-42)aggregation.Therefore,ST might inhibit the formation of Aβ(1-42)aggregation.The apoptosis of Aβ-induced SHSY5Y cells was inhibted by ST mainly through PI3K-AKT signaling pathway,MAPK signaling pathway,Alzheimer’s disease,and apoptosis pathway.(3)The protective effect of ST on AD model nematode showed that,500μg/mL ST could significantly prolong the life of CL2006 and CL4176,improve the motor ability of CL2006 and CL4176,and delay the paralysis of nematodes caused by Aβ.ST could significantly improve the memory ability of CL2355 and enhance the taxis of nematodes.Further studies showed that ST could effectively inhibit the production of ROS and MDA in AD model nematodes,increase SOD activity and play an antioxidant role.ThT assay showed that ST could reduce the accumulation and deposition of Aβ in CL2006 and CL4176.Therefore,ST may play a protective role by inhibiting Aβ accumulation in AD model nematode and alleviating oxidative stress in AD model nematode.The results of this study showed the inhibitory effect of ethanol extract of sweet tea on Aβ-induced neurotoxicity,and further explored the mechanism of action of ethanol extract of sweet tea on SH-SY5Y cells and AD model nematode.This study provide a new direction for AD,and also provides theoretical basis for the development of sweet tea and related products of sweet tea extract.