The Anti-aging Activity Of Dendrobine And Its Action Mechanism Study

According to the statistics of World Bank,99 countries and regions have entered the aging society.The decrease of labor force and the increase of medical burden faced by the aging society seriously hinder the development of social economy.In this situation,how to delay aging and achieve healthy aging is one of urgent problems in the world.Anti-aging drugs,a key point to prevent and treat aging-related diseases,prolong healthspan by postponing aging.The purpose of this thesis is to discover safe and effective molecules with anti-aging activity from traditional Chinese herbs,which could make contribution for anti-aging medicine development.Dendrobium nobile Lindl.,a valuable traditional Chinese herb,exhibits health-improving and lifespan-prolonging effects.Under the guidance of K6001 yeast replicative lifespan system,the methanol extract of Dendrobium nobile was isolated by silica gel column chromatography,and five fractions exhibiting anti-aging activity were obtained.Subsequently,a compound with anti-aging effect was separated from further isolation and purification of the most active fraction by using HPLC.The compound was identified as dendrobine by spectral analysis and comparison with previous literature.Dendrobine extended replicative and chronological lifespans of yeast.In the study of action mechanism:first,the survival rate of yeast was enhanced upon dendrobine treatment under oxidative stress induced by H₂O₂.Additionally,dendrobine decreased the levels of ROS and MDA,and increased the enzyme activities and gene expression of SOD and CAT,but failed to elongate the replicative lifespans ofΔsod1,Δsod2,Δcat andΔgpx yeast mutants.Above results indicate that enhancing the oxidative stress resistance of yeast is one of action mechanisms of dendrobine.Second,dendrobine enhanced autophagy occurrence in YOM38-GFP-ATG8 yeast,but had no effect on replicative lifespans ofΔatg2 andΔatg32 yeast mutants,suggesting autophagy is another mechanism of dendrobine activity.Inhibition of TORC1 leads to the longevity of yeasts,worms,flies and rodents.In yeast,Sch9/Rim15/Msn2 signaling pathway locates downstream of TORC1 and mediates the effect of TORC1 on lifespan.Therefore,the relationship between Sch9/Rim15/Msn2signaling pathway and the anti-aging activity of dendrobine was studied in this thesis.Results showed that dendrobine inhibited Sch9 phosphorylation and promoted the nuclear translocation of Rim15 and Msn2.Moreover,Rim15 mediated the lifespan extension,oxidative stress reduction and autophagy enhancement of dendrobine.Above results demonstrate that dendrobine promotes longevity through Sch9/Rim15/Msn2 signaling pathway.In conclusion,five active fractions and dendrobine were isolated from Dendrobium nobile by utilizing the K6001 replicative lifespan system.And the results of action mechanism reveal that dendrobine exhibits anti-aging activity in yeast via regulation of oxidative stress resistance,autophagy and Sch9/Rim15/Msn2 signaling pathway.All of results in this thesis support the development of Dendrobium nobile as an anti-aging herb.