Studies On The Chemical Constituents Of The Triterpene Acids

Loquat leaf is dried leaves of Eriobotrya japonica (Thunb) Lindl (Rosaceae),used as a traditional Chinese medicine, and recorded in many classic ancient medicalbooks used as treatment of cough.There are three main parts of this thesis. The first part is the chemicalinvestigation of triterpene acids in loquat leaf. The second part is the purificationprocess of S1. The third part is a review on the research progress of triterpene acidsand their biological activity of loquat leaf.Through the chromatography methods of silica gel, reversed phase silica gel,MCI-gel CHP20P, Toyopearl HW-40F, CG161M,14compounds were isolated fromthe loquat leaf including13triterpenoids acids and one phenolic glycosides. Theisolated triterpene acids include usu alkyl-type and oleanane-type pentacyclictriterpenoids, and four compounds are first isolated from this plant. Their structureswere identified through13C-NMR spectroscopy,1H-NMR spectroscopy, and massspectrometry.S1and S2are isomers of oleanane and usu alkyl type pentacyclic triterpenoidacids. The aim of the thesis is to isolate S1from the mixtrue of S1and S2. S12.8g(purity>98%) was obtained and a brief analysis of their separation and purificationmethod.Triterpene acids is the main active component of loquat leaf. The review on theresearch progress of triterpene acids and their biological activity of loquat leaf alsodiscussed herein.