The Intervention Effect And Mechanism Of Polygonum Multijiorum Thumb.on Aging And Neurodegenerative Diseases

Polygonum multiflorum Thunb.belongs to Polygonaceae and its tuberous root is the main medicinal part.It is traditionally considered to increase vitality,improve vascular health,blacken hair,nourish the liver and kidneys,strengthen bones,and extend lifespan.Modern pharmacological studies have also demonstrated that P.multiflorum Thunb.has anti-aging,antioxidant,anti-inflammatory effects,and has great potential in treating neurodegenerative diseases and preventing atherosclerosis.However,the pharmacological basis and molecular mechanism of P.multiflorum Thunb.in anti-aging and aging-related neurodenerative diseases(ND)are still unclear.In this study,we used Caenorhabditis elegans(C.elegans)as a model,combined chromatographic technique,molecular biology and genetics to investigate the therapeutic material basis and mechanism of the P.multiflorum Thunb.in anti-aging and intervention of neurodenerative diseases such as Alzheimer’s disease(AD),Parkinson’s disease(PD)and Huntington’s disease(HD).The main results were as follows:1)The 75% ethanolic extract of P.multiflorum Thunb.was separated by macroporous resin chromatography to obtain two eluted sites containing stilbene(ie.,HSW-60%-Et OH)and anthraquinone(ie.,HSW-95%-Et OH),respectively.We found that the HSW-60%-Et OH extract rich in stilbene significantly extended the average lifespan of C.elegans by 19.82% at 50 μg/m L,while HSW-95%-Et OH extract enriched with anthraquinone did not prolong nematode lifespan at the same concentration.In addition to,HSW-60%-Et OH extract also obviously increased locomotion and pharyngeal pump frequencies,reduced lipofuscin deposition and improved the survival rate of nematodes under oxidative stress by attenuating intracellular reactive oxygen species(ROS).These results indicated that HSW-60%-Et OH extract improved the health indexes and stress resistance of nematodes。2)In order to elucidate the anti-aging mechanism of HSW-60%-Et OH,q RT-PCR and transgenic worms were used.The results showed that HSW-60%-Et OH treatment significantly promoted the nuclear translocation of DAF-16 and SKN-1 into the nucleus as well as the expression of their target genes such as sod-3 and gst-4,but faied to increased the lifespan of daf-16 or skn-1 mutants both under normal and oxidative stress conditions.These findings suggested that HSW-60%-Et OH might mediated longevity and stress resistance dependent on DAF-16/SKN-1 in C.elegans.3)According to High Performance Liquid Chromatography(HPLC)fingerprint analysis,2,3,5,4’-Tetrahydroxystilbene-2-O-β-D-glucopyranoside(TSG)was the main compound in HSW-60%-Et OH,which could prolong the mean lifespan by 16.48%and also significantly improved healthspan of worms at the concentration of 200 μM,as well as obviously improve the nematodes’ ability to resist heat and oxidative stress.It suggested that TSG was the major bioactive component of HSW-60%-Et OH in anti-aging.4)Further studies showed that TSG extended the lifespan of C.elegans via multiple signaling pathways.The results showed that the lifespan extension of TSG was not only dependent on transcription factors DAF-16 and SKN-1,but also related to the improvement of mitochondrial function mediated by SIR-2.1.Moreover,the primary source of ROS production is mitochondrial,whose function was significantly improved in a SIR-2.1 dependent manner after TSG administration.We found that TSG treatment increased both mitochondrial membrane potential(MMP)and ATP content,especially in inhibiting acute mitochondrial dysfunction induced by high glucose or rotenone.The mechanism was related to the co-regulation of mitochondrial biogenesis and PINK1-PDR1-dependent mitophagy,which promoted the renewal of damaged mitochondrial.5)Finally,we investigated the intervention effects of P.multiflorum Thunb.on aging-related neurodegenerative diseases using AD,PD and HD transgenic worms.The results showed that both TSG and HSW-95%-Et OH containing anthraquinones could inhibit Amyloid beta(Aβ)toxicity,especially HSW-95%-Et OH exhibited higher inhibitory activity in a dose-dependent manner at a maximum solubility of 1mg/m L.Furthermore,TSG together with HSW-95%-Et OH were found to markedly prevent Aβ or phosphorylated tau-induced motor impairment and neurotoxicity.Preliminary analysis of its protection mechanism may reduce the accumulation of Aβprotein in worms by enhancing the ability of antioxidant stress and improving the function of mitochondrial.Meanwhile,intervention studies on PD and HD illustrated that HSW-95%-Et OH and TSG were able to suppress the deposition of α-synuclein(α-Syn)and polyglutamine(Poly Q)in vivo,and even the activity of HSW-95%-Et OH is better than that of TSG.Based on the experimental results,it is preliminary speculated that anthraquinones in P.multiflorum Thunb.have more potential in the treatment of neurodegenerative diseases than stilbenes.Altogether,this study elucidated the material basis and mechanism of P.multiflorum Thunb.on anti-aging effect.It revealed that natural chemical compound TSG can enhance longevity in C.elegans via activating antioxidant stress signaling pathway regulated by DAF-16/SKN-1 and improving mitochondrial function mediated by mitophagy and mitochondrial biogenesis.In addition,anthraquinones were identified as one of the main components of P.multiflorum Thunb.in the intervention of neurodegenerative diseases,which could inhibit the accumulation of marker proteins,maintain proteostasis in nematodes,and alleviate motor impairment and neurotoxicity.These results not only provide experimental support for the clinical application of P.multiflorum Thunb.,but also lay a foundation for the development of drugs for anti-aging and treatment of neurodegenerative diseases.