Study On The Functional Factors Of Lepidium Meyenii, A Plant With Medicine And Food Characteristics

The Maca plant (Lepidium meyennii Walp.) has several thousend years history of use as a food and medicine crop in the highlands of Peru. Maca is a highly nutritious food source, and Maca alkaloids, glucosinolates, isothiocyanates, macamides and steroids are probably responsible for its aptitude to act as a fertility enhancer, aphrodisiac, adaptogen, anabolic and to influence hormonal balance. However, the Correspond Relation between the active material basis and functional mechanism are still quite indistinct, and it is widely agreed that one of the main reasons for this is the deficiency of in-depth study on the extraction, separation, chemical composition, chemical structure and content determining of the active material basis.The study in my dissertation was carried out surrounding the active material basis of maca. The study result is:The characteristic of high nutrition of Maca, such as high protein(9.22 %), high branch chain amino acid(20.14% total aa) and high fructose(5.32 %) , was confirmed in the study on nutritional components, and the small amount taurine(0.08 %) and the polysaccharide(6.85 %) with antioxidative activity were found for the first time. Many secondary metabolites of Maca were found using preparatory tests for composition identifying, and the contents of the non-water-solubility alkaloids, sterols, organic acids and essential oils were remarkable.The content of total alkaloids in dried Maca (0.82 %) root can be determined using the titration method rapidly, and the content of glucosinolates in dried Maca root (1.92 %) and in commercial powder of Maca (0.13 %) can be determined using the palladium chloride method rapidly. From the dissolution-degradation kinetics of glucosinolates in Maca, it was found that glucosinolates were losing partially in the tradition process of extract by water or dilute ethanol-soluble, but the losing could cut down by enzyme inactivation and other technical-adjusting measures.TLC solvent system for separating Maca total alkaloids is n-Butanol : ethanol : water : ethylenediamine(38:10:12:1 v/v), and the decoloration by D152 macroreticular weak acidic acrylic acid resin can wipe off the coloring matter effectually and the recuperation rate obtained is higher than 88 %. Three imidazole alkaloid (lepidiline A, B, C) in J5 was affirmed by LC-MS. Furthermore, lepidiline C is a new compound found in Maca, and lepidilines have the potential research on heart function regulation. Natural plants with similar appearance or medicinal effects, including Maca(peru Maca and Huizhe Maca), radish, oriental ginseng and American ginseng were investigated. Their alkaloid extracts of the hypogeal parts were analyzed by FTIR and TLC. The essential oils were analyzed by GC/MS. Through comparison of the characteristics of their spectra and chromatograms, it was found that the functional ingredient extracts of Maca have unique FTIR and GC behaviors. The secondary amide group, conjugated carbon-carbon double bond and phenyl structure in FTIR and the characteristic peaks produced by the major essential oil components (Phenylacetonitrile, Benzaldehyde, 3-Methoxyphenylacetonitrile, etc) in GC/MS are distinct. These behaviors can be applied to the identification of Maca or Maca products in the market.The mice′s LD50 of dried Maca root was found higher than 10.00 g/kg.BW in acute toxicity test, and the results of Ames test, mice bone marrow micronucleus test and mice sperm malformation test are of negative. The long term toxicity test indicated that the level of female AST in medium and high dose groups, TCH in high dose groups significantly decreased than in the control group, however the changes of other indexes were not significantly different between the Maca groups and control group (P>0.05). All results indicated that Maca had a higher food safety level.The anti-fatigue effects of dry maca powder were proved to be remarkable through animal experiments, and in comparison with control groups, the urea level in blood serum of fatigued mice decreased, the glycogen level in liver increased, the raise of blood lactic acid level during movement was restrained, the blood lactic acid decrease of mice after movement was accelerated. In the study of the experiments on immune regulation, Maca was shown to enhance cellular immunity, but had no effect on humoral immunity, non-specific immunity and NKC activity. However, the mixture of Maca and American ginseng general ginsenosides can enhance immune function of mice significantly, and Maca was shown the synergistic action.