Study On The Antidepressant And Sleep-improving Effect And Mechanism Of Maca (Lepidium Meyenii) Extract

As the society develops, people’s living pressure from every aspect lead to increasingmorbidity of insomnia and depression from year to year. As the treatments for thesediseases, western medicine has many side effects, high prices and poor treatment response.Therefore, it is an important task to develop new drugs with low toxicity, low price andhigh effects.Lepidium meyenii(Maca) is a Cruciferae Lepidium plant used as food as well asmedicine. Maca has many particular pharmacological effects. However，direct evidencesfor the antidepressant and sleep-improving effect of Maca are rarely reported. The relatedactive substance and action mechanisms are not clear, either. To solve these problems, westudied effects of anti-depression and sleep-improving quality. At the same time, weexplored its action mechanisms of these effects. We also analyzed the chemicalcomponents and its contents of the active fraction in Maca. Finally, we did safetyevaluation for Maca. The results of the whole study will provide theoretical basis andscientific evidences for developing related drugs or health products.1. We built chronic unpredicted stress mice model to study the sleep improving andantidepressant effect of water soluble and lipid soluble active section of Maca. We foundthat the lipid soluble section of Maca extracts have such pharmacological effects andshowed significant differences in tail suspension test (TST) and open field test (OFT).2. We localized the active components as petroleum ether extract of Maca and studiedthe dose-effect relationship for antidepressant effect and sleep improving effect. Throughpathological section of mouse brain tissue observation, detection of physiologicalindicators in blood serum and animal behavior observation, we found that Maca hassignificant antidepressant effect. The underlying mechanism was explored by determiningthe level of cerebral monoamine neurotransmitters and activity of reactive oxygen species(ROS). The medium and high dose of Maca petroleum either extract significantly reducedthe ROS level in mouse brain tissues and increased noradrenalin (NE) and dopamine (DA)levels. These results demonstrated that the petroleum ether extract from maca showedantidepressant-like effects and the mechanism of action is related to the activation of both noradrenergic and dopaminergic systems as well as attenuation of oxidative stress inmouse brain.3. We also analyzed specific chemical components of Maca petroleum either extracts.We found that the content linoleic acid and linolenic acid in petroleum either extracts areall about0.1%. The content of Macamide is about0.0223%.In acute toxicity test of Maca,no death happened in14days. These results indicate that the maximum tolerated dose ofMaca petroleum either extracts is16g/kg·BW.