Study On The Anti-fatigue Effective Constituents And Mechanisms Of Maca

Maca, a kind of medical and edible plants, possess extensive pharmacological activities, the anti-fatigue effect of maca is the cornerstone to support the product market of maca and its development. However, the existing researches on the anti-fatigue effect of maca focused on exercise-induced fatigue resistance, there is no reports on the centralfatigue resistance effect of maca. Also, the existing researches seldom involve the analysis of the anti-fatigue chemical constituents of maca and the systematical mechanism study. This study investigated the anti-fatigue effects and the dose-effect relationship of maca root powder firstly. According to the results of weight-loaded swimming test and the biochemical parameters, appropriate dosages of maca for anti-fatigue effect were detemrined. Then, the effects of exercise-induced fatigue resistance and central fatigue resistance of maca liposoluble extract(MLE) were evaluated by the fatigue animal models. The chemical components of MLE with anti-fatigue activity were analyzed. Further, the monomer compounds with anti-fatigue activity were determined, and the anti-fatigue mechanisms were researched on energy metabolism, antioxidant, molecular biology three aspects. The main results are as follows:1. The anti-fatigue effects and the dose-effect relationship of maca root powder were studied. Middle-high dose group of maca(3 g/kg) and high dose group of maca(10 g/kg) could significantly extend the weight-loaded swimming time; increase the hepatic glycogen(LG) content; reduce the serum lactic acid(LD) and serum urea nitrogen(BUN) levels. There is a dependent relationship between the effects and the doses.2. The effects of exercise-fatigue resistance and central-fatigue resistance of MLE were evaluated by the fatigue animal models. Low and high dose groups of maca liposoluble extract(60, 200 mg/kg) could significantly extend the weight-loaded swimming time in mice, increase liver glycogen(LG), muscle glycogen(MG) levels, and the non-esterified fatty acid(NEFA); reduce the serum lactic acid(LD), blood ammonia(BA), and serum lactic acid dehydrogenase(LDH) activities, attenuate exercise-induced fatigue. “Flower pot technique” was used to establish the sleep deprivation model that resulted to central fatigue in mice, the central fatigue resistance effects of MLE were studied. The central-fatigue resistance effects were researched on three aspects, such as animal behavior observation, pathological section observation of brain tissue and the measurement of biochemical parameters. These results showed that supplementation with maca liposoluble extracts(200 mg/kg) could effectively alleviate central fatigue, such as improving learning and memory ability, and decreasing the damage of hippocampal structures in sleep deprived mice. The mechanism can be explained by improving the antioxidant ability of the brain,and has nothing to do with the contents change of monoamine neurotransmitters in the brain.3. The components of MLE were analyzed by chromatography-mass spectrometer(GC-MS) and high performance liquid chromatography(HPLC). It contains linoleic acid, linolenic acid, palmitic acid, oleic acid, stearic acid, and about 20% total macamides, which with the higher contents were 6.63% N-benzylpalmitamide, 4.59% N-benzyloleamide and 4.22% N-benzyllinoleamide.4. The anti-fatigue effects of three main macamides in maca liposoluble extract were studied. N-benzyloleamide was found to be the important anti-fatigue active constituents in maca. High dose group of N-benzyloleamide(40 mg/kg) could significantly extend the weight-loaded swimming time; reduce the serum lactic acid(LD), blood ammonia(BA), and serum lactic acid dehydrogenase(LDH) activities; increase the non-esterified fatty acid(NEFA), liver glycogen(LG) and muscle glycogen(MG) levels. Also it could significantly reduce the malondialdehyde(MDA) levels, increase the superoxide dismutase(SOD) and glutathione peroxidase(GSH-Px) activities in the brain, muscle and liver of mice. In addition, it could significantly improved Peroxisome Proliferator Activated Receptor?(PPAR?) and PPAR? co-activator(PGC-1?) m RNA expression levels in the skeletal muscle of mice. The results indicate that N-benzyloleamide has pharmaceutical effect against fatigue, and this effect can be explained by modulating energy metabolism and improving the antioxidant status.These results have laid a theoretical basis for the researches of maca products on exercise-induced fatigue resistance and also central fatigue resistance.