Studies On The Chemical Constituents Of Two Yunnan Medicinal Plants

This dissertation covers three chapters.Chapter 1 reviewed the structures and bioactivities of phloroglucinol derivatives from the family Myrtaceae since 2000.Syzygium brachyantherum and Euphorbia tirucalli,which were collected in Yunnan Province,China,have been phytochemically studied in chapters 2 and 3,respectively.In chapter 1,52 phloroglucinol derivatives isolated from the family Myrtaceae since 2000 were summarized.A detailed list of their structures,names,plant sources,biological activities,along with the references were given in this chapter.In chapter 2,the phytochemical investigation of the the leaves parts of Syzygium brachyantherum was described.S.brachyantherum,belonging to the genus Syzygium,which is mainly distributed in Yunnan,Hainan and some other prefectures in China.So far the report on its chemical constituents has not been characterized.With the alternate use of modern chromatography techniques,26 compounds,including 15 new phloroglucinol derivatives,were obtained from the MeOH extract of the leaves plant of S.brachyantherum.The structural types of the isolates cover phloroglucinol derivatives,triterpenoids,anthraquinones,and phenolic acids,etc.All the compounds were isolated from this plant for the first time.In chapter 3,the phytochemical investigation of the the aerial parts of Euphorbia tirucalli was described.E.tirucalli,belonging to the genus Euphorbia,which is widely cultivated in tropical and subtropical,North and South of China are cultivated.By the means of various chromatography methods,23 compounds,including one new ionol derivative,were isolated from the ethyl acetate extract of the aerial parts of E.tirucalli.The chemically structural types of the isolates include ionol derivatives,diterpenoids,flavonoids,lignans,anthraquinones,and phenolic acids,etc.Compounds 27–36,38–43 and 45–48 were firstly isolated from this plant.