Antimalarial Constituents Of Scutellaria Likiangensis And Pharbitis Purpurea

This thesis consisted of four chapters and the work during the master’s study is summarized.In the first chapter,the antimalarial activity of 204 plants from West Yunnan were evaluated and reported.In the second chapter,the chemical constituents of Scutellaria likiangensis and their in vivo antimalarial activities of some selected compounds were present.In the third chapter,the chemical constituents of n-butanol fraction of Pharbitis purpurea and theirβ-hematin formation inhibition activity were studied.And the research progress of bc1 complex inhibitors for Plasmodium was summarized in the last part.Objective:（1）To search for natural antimalarial components from plants.（2）To study chemical constituents of the roots of S.likiangensis and identify monomeric components with antimalarial activity in vivo,laying the foundation for the search for new antimalarial drugs.（3）To study the compositions and hemozoin formation inhibition activity of the n-butanol fraction of P.purpurea.Methods:The four-day suppressive test was used to screen the antimalarial activity in vivo of 204 plant samples from West Yunnan.The compounds were isolated and purified by using various column chromatographic methods,and their structures were identified based on spectral analysis.The antimalarial activity of partial monomers of S.likiangensis was tested by rodent malaria model.The potential antimalarial activity of P.purpurea was evaluated byβ-hematin formation inhibition activity experiment.Results:1.Antimalarial activity screening of the plants from West Yunnan:among the204 plants,10 plants showed different antimalarial activity in vivo.The codes of the active samples were 0719BE,0787AE,0808AE,0816BE,0817BE,0820AE,0823BE,0859BE,0861BE,and 0877AE.Their Plasmodium·yoelii inhibition rates were:23.93%,28.88%,28.58%,26.25%,26.52%,32.10%,25.80%,21.31%,28.78%,and27.31%,respectively.2.Chemical constituents and antimalarial activity of S.likiangensis:twenty-six monomeric compounds were isolated and identified from the 75%Et OH-H₂O solution of the roots of S.likiangensis and identified as chrysin（1）,3-methylethergalangin（2）,5,7,2’-trihydroxy-6-methoxyflavone（3）,5,7,2’,6’-tetrah-ydroxyflavone（4）,6-C-glucosy-lchrysin（5）,kaplanin（6）,isovitexin-2"-O-β-D-glucopyranoside（7）,oroxylin A-7-O-β-D-methyl glucuronide（8）,chrysin-7-O-β-D-methyl glucuronide（9）,oroxylin A-7-O-β-D-glucoside（10）,oroxylin A-7-O-β-D-glucuronide（11）,（2S）-5,7-dihydroxy-6-methoxy flavanone（12）,scuteamoenin（13）,（2S）-5,7,2’-trihydroxy-6-methoxyflavanone（14）,（2R）-5,7,2’,6’-tetrahydroxyflava-none（15）,（2R,3R）-3,5,7,2’,6’-pentahydroxy-flavanone（16）,（2S）-dihydrooroxylin A-7-O-methyl glucuronide（17）,scumonilioside B（18）,（2S）-dihydrooroxylin A-7-O-β-D-glucuronide（19）,cistanoside D（20）,3-hydroxy-trans-stilbene-5-O-β-D-glucoside（21）,ursolic acid（22）,oleanolic acid（23）,syringare-sinol-4’-O-D-monoglucopyranoside（24）,pinosylvin（25）,and glyceryl monooleate（26）.The compounds 8,10,11,and 17 showed certain antimalarial activity,with inhibition rates20.01%,12.90%,13.90%,and 19.93%.3.The chemical constituents andβ-hematin formation inhibition activity of n-butanol fraction of P.purpurea:thirteen compounds were isolated from n-butanol fraction of 75%Et OH-H₂O solution of the whole herb of P.purpurea,and were identified as kaempferol-3-β-D-（6-O-cis-p-coumaroyl）glucopyranoside（1）,isoorientin（2）,apigenin-7-O-β-D-glucopyranoside（3）,kaempferol-3-O-β-D-gluco-pyranoside（4）,vitexin（5）,skimming（6）,daucosterol（7）,adenosine（8）,2’-O-（9Z,12Z,15Z-octad-ecatrienoyl）glycerylβ-D-galactopyranoside（9）,N-trans-feruloy-ltyramine-4’-O-β-D-glucopyranoside（10）,methyl 4,5-di-O-caffeoylquinate（11）,1H-indazole（12）,and 1-（β-D-ribofuranosyl）-1H-1,2,4-triazone（13）.The results of hemozoin formation inhibitory activity test showed compounds 2 and 11 have a certain inhibition activity at the test concentration.It is suggested that the n-butanol fraction of P.rotundifolia may also have potential antimalarial activity.Conclusion:1.There were 10 plants of the 204 representative plants collected from Western Yunnan showed different antimalarial activity in vivo.2.Compounds 6,7,21,24-26 were isolated from Scutellaria genus for the first time,and While compounds 2,4,5,8-20,and 22,23 were isolated from S.likiangensis for the first time,and flavonoids were the major constituents of them.The results of antimalarial activity in vivo showed that the antimalarial activitiy of the individual compound was not high,and the antimalarial activity of S.likiangensis might be due to a synergistic effect of several compounds.3.Compounds 2-6,and 9-13 were isolated from the genus Pharbitis for the first time.The types of the constituents involve flavonoids,coumarins,and glycosides.The bioactive test indicated that compounds 2 and 11 showed certainβ-hematin formation inhibition activity,and the n-butanol fraction of P.purpurea may have some potential antimalarial activity.