Biological Effects Of Water-soluble Polysaccharide From Pueraria Lobata And The Mechanism Of Extending C.Elegans Lifespan Under Heat Stress

Pueraria lobata is the dried root of the legume Pueraria,which has a positive regulatory effect on the brain and cardiovascular system,and also has a good therapeutic effect on diabetes and alcohol dependence.At present,there are few studies on the bioactivity and mechanism of water-soluble polysaccharide(water-soluble polysaccharide,WSPS)from Pueraria lobata.Therefore,we mainly investigated the antioxidant activity and mechanism of WSPS.The research results are of great significance for the rational application of Pueraria polysaccharide and the development of antioxidant drugs.First,WSPS was obtained from Pueraria powder by ultrasonic assisted water extraction,and its polysaccharide content and composition,characteristics of UV absorption and infrared absorption were determined.The results showed that the WSPS extracted had glycosidic bond.The main component of WSPS was glucose,and a small amount of mannose and xylose were also found by HPLC.The antioxidant activity of WSPS was evaluated by free radical scavenging experiments in vitro.It was found that WSPS could scavenge DPPH·and·OH with a dose-response relationship,indicating that WSPS had antioxidant activity.Secondly,the effects of different concentrations of WSPS on body length,reproduction and locomotive behaviors of Caenorhabditis elegans(N2,wild type)were studied.The results showed that low concentration of WSPS(20,40 mg/L)had no effect on the body length and number of eggs laid,but it could enhance the locomotive behavior.That is,increase the head thrash and body bend frequencies,while higher concentrations of WSPS could not only increase the body length and the number of eggs laid,but also improve the locomotive ability,indicating that the locomotive behavior of nematode was more sensitive to WSPS.At the same time,all concentrations of WSPs can alleviate the shortening of nematode body length and life span under heat stress at 37?,suggesting that WSPS can protect the nematode.Finally,in order to explore the mechanism of the protective effect of WSPS on C.elegans under heat stress,we tested the biochemical indicators and the expression levels of related genes in the worm.The results demonstrated that WSPS could significantly increase SOD activity,decrease ROS level,MDA content,and increase the expression of antioxidant gene(sod)and stress-related genes(hsp,skn),indicating that WSPS could attenuate the heat stress-induced damages by increasing the expression of some antioxidant genes and stress-related genes,so as to increase the line the body length and the longevity of the nematode.