Study On The Chemical Constituents Of Syzygium Jambos And Syzygium Austroyunnanese

This paper is composed of three chapters.The first chapter reviews the researches of the chemical constitutents and biological activities of triterpenes from the genus Syzygium since 1994.In the second and third chapter,the chemical constituents of Syzygium jambos and Syzygium austroyunnanese were studied,respectively.In the first chapter,the structures,plant sources and biological activities of 59 triterpenes from the genus Syzygium,were reviewed since 1994.In the second chapter,the leaves of S.jambos were isolated and their chemical compositions were reported.It is native to the China and India peninsula,Malaysia and Indonesia,and was cultivated in Yunnan,FuJian,Taiwan,Guangxi,Guangdong,Guizhou and Hubei provinces.S.jambos can be used for the treatment of toothache,oral ulcers,and cough.In order to obtain the compounds for further bioactive research,the leaves of S.jambos were studied by various chromatography methods including silica gel chromatography,Sephadex LH-20 gel chromatography,MCI,and HPLC,and 28 compounds were isolated and identified,among them,3 compounds were new,all but compounds 9,15,23,and 24 were firstly isolated from the genus.Compound types covered lacquer acid derivatives,resorcinol derivatives,triterpenes,flavonoids,and phenolic acids.In the third chapter,the chemical constituents of ethyl acetate of Syzygium austroyunnanese,collected in Xishuang Bannan Prefecture,were studied.Syzygium austroyunnanese belongs to Myrtaceae,which is mainly distributed in Xishuang Banna of Yunnan and Hengxian of Guangxi Province.In our continuing research program with the aim of discovering more structures with bioactivities,we have investigated the ethyl acetate extracts of S.austroyunnanese,and isolated 12 compounds,including two new compounds,compounds 29-40 were isolated from this plant for the first time.Their structures include tannin,phloroglucinol derivatives,flavonoid glycosides,,triterpenes and phenolic acids,were determinedon the basis of various spectral techniques.