| Lepidium meyenii Walp.belongs to the genus Cruciferae.It is an important medicinal and food plant in Yunnan.This dissertation mainly studies the structure identification and biomimetic synthesis of two novel sulfur-containing alkaloids in Lepidium meyenii Walp.produced in Lijiang.This dissertation consists of four chapters.The first chapter mainly introduces the botany overview,activity research status and chemical composition research of Lepidium meyenii Walp produced in Lijiang.The second chapter introduces the chemical composition of Lepidium meyenii Walp produced in Lijiang,and identifies two novel relative configurations of sulfur-containingalkaloids.MeyeniinsA-C（1-3）,Novel Hexahydroimidazo[1,5?c]thiazole Derivatives and macahydantoin C（4）,a new thiohydantoin with a 1,3-diazabicyclo[3.3.1]nonane core,The structure is:The third chapter focuses on the biomimetic synthesis of meyeniins A-C（1-3）,and determines the absolute configuration of meyeniins A-C（1-3）in combination with single crystal diffraction.In this biomimetic synthesis,two key reactions were involved:condensation reaction and Edman degradation reaction.On this basis,a mixed crystal of（±）-meyeniin A was obtained,and its absolute configuration was determined by X-Ray.At the same time,it was found that the racemate of the compound is easily obtained as a high-quality crystal for X-ray single crystal diffraction,while any of its enantiomers as oily compounds can not obtain crystals.Finally,the absolute configuration of meyeniins A-C（1-3）was determined in comparison with the CD data.Activity screening showed that（+）-meyeniin A showed selectivity activity on HL-60,A549 and MCF-7 human cell lines with IC50 of 14.41,32.22 and 33.14μM,respectively.The fourth chapter mainly introduces the biomimetic synthesis and structural modification of macahydantoin C（4）.The preliminary chemical composition study showed that our compound macahydantoin C（4）was similar to the structure of macahydantoin B reported in the literature,but the spectral data was quite different.Therefore,we suspect that the structure of macahydantoin B reported in the literature may be problematic.In order to determine this inference,this paper carried out biomimetic synthesis studies on the structures of reported macahydantoin B and revised macahydantoin B,respectively.Finally,through the spectral comparison,the literature reported that the 1,3-diazabicyclo[3.3.1]nonane skeleton of macahydantoin B was modified to have 4-methyl-hexahydropyrrolo[1,2-c]imidazole skeleton.The study further revealed the material basis and pharmacodynamics of Lepidium meyenii Walp.,an important resource plant in Yunnan,and novel types of sulfur-containing alkaloids have been discovered through separation,identification,biomimetic synthesis,and biological activity.And revised macahydantoin B as a novel sulfur-containing alkaloid.Its research supports the application of maca as a preventive diet in functional foods to some extent. |
