Study On The Chemical Constituents Of Two Medicinal Plants Of The Syzygium

Syzygium is an important member of Myrtaceae family.There are about 500species in the world,mainly distributed in the tropical regions of Asia.Syzygium plants have a long history of edible and medicinal value,and their flower,seed and bark have been used to treat diabetes,dysentery and other diseases.In recent years,our research group has carried out chemical study on Syzygium species,and found a series of active ingredients,including triterpenoids,flavonoids,anacardic acid,resorcinol,and phloroglucol.Anti-diabetic activity screening exhibited that anacardic acid,resorcinol,and phloroglucinol constituents have significant inhibitory activity against?-glucosidase and protein tyrosine phosphatase 1B.Therefore,we continue to research on chemical constituents of the genus Syzygium in Xishuang Banna.This paper is divided into three chapters.In chapter 1,the chemical constituents of natural products with a-glucosidase inhibitory activity since 2009 were reviewed,and the structure,name,half inhibitory concentration(IC₅₀)and the mechanism of some compounds were listed in detail,which provide some references for the development of diabetes drugs.In chapter 2,a systematic chemical composition study was carried out on the leaves of Syzygium fluviatile Merr.et Perry from Xishuang Banna Autonomous prefecture of Yunnan Province.Up to now,there has not report on the chemical constituents of S.fluviatiler.This experiment including comprehensive separation methods?positive and negative phase column chromatography of silica gel column chromatography,Sephadex LH-20,medium voltage preparation chromatography,high performance liquid chromatography?HPLC?,etc.?and spectroscopy techniques from 70%aqueous acetone extract of this species.A total of 63 compounds covering12 new ones were identified,and the structural types involvs triterpene,diterpene,sesquiterpene,phloroglucinol,steroids,tannins,flavonoid,etc.All compounds were isolated from the genus Syzygium for the first time.By performing?-glucosidase inhibitory activity test on some of the compounds,it was found that compounds 1,2,3,8 and 9 showed significant?-glucosidase inhibitory activity.In chapter 3,the chemical constituents were studied on the ethyl acetate extracts of the leaves of Syzygium latilimbum collected from Xishuang Banna Autonomous prefecture of Yunnan Province.In order to further study the chemical constituents in the S.latilimbum,we continue to study the ethyl acetate extract of the S.latilimbum.14 monomeric compounds were isolated and identified by various modern separation techniques and spectral methods.These compounds mainly included triterpenoids and phenolic acids.All compounds were firstly isolated from this plant.