Study On Anti-Aging Activity And Molecular Mechanism Of Lycium Barbarum Polysaccharide Based On Drosophila Melanogaster

Lycium barbarum is a kind of famous traditional Chinese medicine plants,mainly growing in northwestern china.The studies have shown that polysaccharides are one of the most important active ingredients in the fruit of Lycium barbarum.There are lots of studies have been reported about chemical structures and bioactivities of Lycium barbarum polysaccharides(LBP),there are few reports about its anti-aging activity.Usually,Crude L.barbarum polysaccharide was used to detect the anti-aging ability and the specific active components of them remain to be identified.In this study,we used stepwise purification methods to generate three polysaccharide preparations of LBP(LBP,LBP-1,and LBP-2)and explored their effects on lifespan extension in Drosophila.The findings of this study provide some basic information that co?Ld give guidance for practical applications of this LBP.The res?Lts were as follows:1.The components of LBP,LBP-1 and LBP-2 were obtained by water extraction,dialysis and protein removal.The physicochemical properties of LBP fractions were characterizated based on gas chromatography,high performance gel permeation chromatography.The res?Lts show that monosaccharide composition of LBP was glucose with molec?Lar weight in the range of1×10 ~3-4×10 ~3 Da.The monosaccharide composition of LBP-1 was rabinose(38.8%),glucose(28.18%),and galactose(25.98%).Two peaks in HPLC spectrum with molec?Lar weight of 9×10 ~4 Da and 2.7×10 ~5 Da represented arabinogalactan and protein,respectively.LBP-2 presented one symmetrical peak of arabinogalactan in the HPLC spectrum with a homogenous molec?Lar weight of 9×10 ~4 Da,whose monosaccharide composition was arabinose(43.09%),glucose(18.84%)and galactose(30.22%).The carbohydrate contents of LBP,LBP-1,and LBP-2 were 58,50,and 54%,respectively.The protein contents of LBP,LBP-1,and LBP-2 were 41.2,46.6,and 27.6%,respectively.2.we aimed to evaluate the effect of a crude L.barbarum polysaccharide and two derived fractions,LBP-1 and LBP-2,on the lifespan of Drosophila melanogaster(fruit fly).LBP supplementation prolonged the mean lifespan by 8.9–16.2%in males and 4.8-19.2%in females.In vivo analysis of antioxidant activities detected increased superoxide dismutase(SOD)and catalase(CAT)activities and decreased malondialdehyde(MDA)levels.Dietary LBP supplements significantly reduced the mortality rate of fruit flies induced by paraquat and hydrogen peroxide.The res?Lts of activity assay showed that the order of anti-aging activity was LBP-2>LBP-1>LBP.The res?Lts indicated that the arabinogalactose(molec?Lar weight9×10 ~4 Da)fraction is the main active component of anti-aging.3.The mechanism of anti-aging molec?Les of LBP was studied by RT-PCR.The res?Lts showed that:The anti-aging activity was,at least in part,mediated by an aging-related signaling pathway MAPK(mitogen activation protein kinases),TOR(Target of rapamycin),S6K(RPS6p70-protein kinase)and the genes Hep(hemipterus),MTH(Methuselah),and Rpn11.