Anti-fatigue And Antidepressant Effects Of The Polysaccharides From Panax Ginseng C.A. Meyer And Their Mechanisms

Panax ginseng C. A. Meyer (ginseng) as a famous plant medicine has diverse phamacological effects. Specially, its anti-fatigue and antidepressant activities have been confirmed through the modern pharmacological research on traditional Chinese drug. Being the active components of ginseng, ginseng polysaccharides have effective anti-fatigue and antidepressant effects, but little research on the effects has ever been reported.Ginseng polysaccharides were prepared following the methods built in our lab before, ginseng total polysaccharide WGP was prepared by hot water extraction, ethanol precipitation and destarch from the root of Panax ginseng C. A. Meyer. WGP was loaded on DEAE-cellulose column. The column was eluted first with distilled water to elute the unbound fraction WGPN and then with 0.5 M NaCl to elute the bound fraction WGPA. The polysaccharide components of WGPA-A have been confirmed as RG-I, HG and AG-rich pectin. WGPA was reloaded on DEAE-cellulose column, and it was isolated into the neural AG polysaccharide WGPA-N and the acid RG-I and HG-rich pectin WGPA-A. The anti-fatigue and antidepressant effects of the fractions of ginseng polysaccharide and their possible mechanisms were studied by orally administrated way in mice.The anti-fatigue effects of WGP, WGPN and WGPA and their dose-effect relations were investigated through the results of the forced swimming test and the serum biochemical tests in mice. It was confirmed that 200 mg/kg is the most optimum dosage of the anti-fatigue effects of WGP and WGPA. The anti-faitgue effects of WGPA-A and WGPA-N were compared and the results showed the effects of WGPA-A whose structure is RG-I and HG pectin was more significant than that of WGPA-N. The resuts were evaluated by the forced swimming test, the serum biochemical tests and the morphological changes of mitochondria in striated skeletal muscle. The anti-fatigue mechanisms were mainly focused on①directly antioxidative effects or increasing the activities of antioxidant enzymes, reducing the myocardial damage of membrane structure of mitochondria or cells, alleviating the fatigue mediated by oxidative stress;②significantly promoting fat utilization of mice during exercising, sparing the consumption of blood glucose and therefore delaying fatigue mediated by energy exhaustion;③significantly decreasing the accumulation of lactic acid the metabolic products of fatigue, and decreasing its inhibition to central nervous systerm.Based on the close connection and part of similar mechanisms between depression and fatigue, the antidepressant effects of ginseng pectin WGPA and its possible mechanisms were also studied in the present paper. WGPA was orally administrated to mice and some behavioral tests including the spontaneous activity test, the elevated plus-maze test, the social interaction test and the forced swimming test were performed, the results showed that WGPA has the significant antidepressant effects. To elucidate the antidepressant mechanisms of ginseng pectin, the neuronal signaling pathways of ERK and GSK-3βwere studied in the present paper. BDNF andβ-Catenin as the important targets of the pathways were tested with the Western Blotting analysis, the results showed that the antidepressant mechanisms of WGPA were mainly through up-regulating the expression of target protein BDNF andβ-Catenin in the ERK and GSK-3βsignaling pathway.