Study On Chemical Constituents With Antimalarial Activity From Dobinea Delavayi

This thesis composed of three chapters is summarized the research works during the master’s study.In the first chapter,the isolation and identification of the chemical constituents of Dobinea delavayi were described.In the second chapter,the study of antimalarial activity of compounds isolated from D.delavayi was presented.And in the last part,the research progress of natural antimalarial sesquiterpenoids was elaborated.Objective: To study the chemical constituents and find the lead compounds with antimalarial activity from roots of D.delavayi.Methods: Through using all kinds of column chromatography methods(such as silica gel,Sephadex LH-20 and MCI),the compounds were isolated and purified.Thier chemical structures were identified by physicochemical properties and spectral analysis methods(NMR and LC-MS).The antimalarial activity of the selected compounds was determined by rodent malaria model(four-day suppressive test)andβ-hematin formation inhibition test.Results: Twenty-one compounds were isolated from Et OAc and n-butanol fractions of the 80% ethanol extract of roots of D.delavayi and identified as dobinin P(1),dobinin Q(2),dobinin R(3),dobinin C(4),dobinin S(5),dobinin T(6),dobinin U(7),dobinoside A(8),dobinoside B(9),2,6,3’,4’-tetrahy-droxy-4-methoxybenzophenone(10),dodeloside A(11),dodeloside B(12),dodeloside C(13)、4-O-β-D-glucopyranosyl-2,6,4’-trihydroxybenzophenone(14),1,6,7-trihydroxy-3-methoxyxanthone(15),mangiferin(16),eriodictyol(17),dodeloside D(18),ombuoside(19),butin(20),and 2-hydroxy-3-(3,4-dihydroxyphenyl)-acrylic acid(21).Compounds 2,3 and 8 showed weak antimalarial activity(Inhibition 7.8%,13.9% and6.4%,respectively)at the dose of 25 mg/kg/day.In addition,compound 21 showed better β-hematin formation inhibition activity(Inhibition 73.3%)at the concentration of 55.6 μg/m L.Conclusion: After searching by Sci Finder,compounds 1-3,5-9,11-13 and 18 isolated from D.delavayi were identified as new compounds.In addition,compound21 was isolated from natural products for the first time and compounds 14,17,19 were separated from the plant for the first time.Referring to relevant literature reports found that sesquiterpenoids are the major chemical constituents of the plant.Compounds 2,3,8 and 21 may be the part of antimalarial constituents of the plant.