The Actival Anti-bacterial Screening Of Leaves Of Dracontomelon Dao On P.aeruginosa And The Investigate Of Material Foundation

Objecttive The aim of this study was to screen out the actival anti-bacterial fraction from the leaves of Dracontomelon dao on P.aeruginosa,and to obtain the chemical constituents from the actival fraction by taking advantage of the isolation,purification and identification means,and to evaluate the anti-P.aeruginosa activity of the main chemical constituents in the actival fraction.This work would contribute to investigate the anti-bacterial mechanism and provide the quality control basis of the leaves of Dracontomelon dao as a potential treating cutaneous infection drug.Method Firstly,the grinded leaves of Dracontomelon dao was heated refluxed and extracted with 90%alcohol,and the actival anti-bacterial of leaves of Dracontomelon dao on P.aeruginosa was screened out based on the systematic solvent extraction mean and microcalorimetry method.Secondly,the screened actival anti-P.aeruginosa fraction of leaves of Dracontomelon dao was carried on various chromatography materials to isolate and purify compounds as much as possible,main including plate chromatography,gel silica column chromatography,MCI column chromatography,ODS column chromatography,sephadex LH-20 column chromatography,liquid preparative chromatography and high-performance liquid chromatography.Besides,the the recrystallization method was also uced for further purifying target compound.Moreover,their structures of the obtained compounds were identified by the spectral analysis,main including mass-spectrography and nuclear magnetic resonance(¹H NMR and ¹³C NMR)and chemical evidence.Eventually,the marked compounds were seclected out based on literature research and the anti-P.aeruginosa activity of the marked compounds from the leaves of Dracontomelon dao were evaluated by microcalorimetric method.Result This actival anti-P.aeruginosa fraction from the leaves of Dracontomelon dao was the ethyl acetate extract in this work,the median inhibitory concentration?IC50?to P.aeruginosa was 18.06?g/mL.The compounds in the actival anti-P.aeruginosa fraction were isolated and purified by taken advantage of various chromatography,and the compounds were analyzed and confirmed by the spectral analysis,main including mass-spectrography and nuclear magnetic resonance(¹H NMR and ¹³C NMR)combined with literature of chemical evidence.The structures of19 compounds from the 21 obtained compunds were elucidated on the basis of physic-chemical properties and spectrum data.Respectively,the compounds were?-sitosterol?1?,gallic acid?2?,methyl gallate)?3?,ethyl gallate?4?,dimethyl?R?-hexahydroxy diphenoate?5?,p-digalloyl acid?6?,m-digalloyl acid?7?,methyl-p-digallate?8?,methyl-m-digallate?9?,ethyl-p-digallate?10?,ethyl-m-digallate?11?,luteolin?12?,quercetin?13?,4H-1-Benzopyran-4-one,2-?3,4-dihydroxyphenyl?-3,5,7-trihydroxy-8-[1-?4-hydroxyphenyl?ethyl]-?14?,4H-1-Benzopyran-4-one,2-?3,4-dihydroxyphenyl?-3,5,7-trihydroxy-8-[1-?4-hydroxy-3-methoxyphenyl?ethyl]-?15?,cupressuflavone?16?,3,5,7-trihydroxy-2-{4-methoxy-3-[4-?3,5,7-trihydroxy-4-oxochroman-2-yl?phenoxy]p henyl}chroman-4-one?17?,quercetin 3-O-?-glucopyranoside?18?,quercetin 3-O-?-galactopyranoside?19?.Compounds 1-19 were isolated and reported from this leaves of Dracontomelon dao for the first time.Especially,the compound 14 and 15were acquired firstly as natural products from the leaves of Dracontomelon dao.Moreover,the compound 17 with a bihydroflavonol structure based on the connection of two taxifolin units was discovered as new natural product named taxifolin-?4`?O?3```?-4```-methoxy-taxifolin.The compounds 1-19 all had the antimicrobial activity on the basis of relative literatures,and the catechins,epicatechin,quercetin,luteolin,quercetin3-O-?-glucopyranosideandquercetin3-O-?-galactopyranoside were selected to perfrom anti-P.aeruginosa activity evaluation experiment,and the quercetin,luteolin,quercetin 3-O-?-glucopyranoside and quercetin 3-O-?-galactopyranoside were have the anti-P.aeruginosa activity in vitro,excluding catechins and epicatechin.The antibacterial strengthen in tested compounds of luteolin was the most strong and sequence of anti-P.aeruginosa activity was luteolin>quercetin>quercetin 3-O-?-glucopyranoside>quercetin3-O-?-galactopyranoside.Conclusion There were main two class obtained compounds,including phenolic and flavonoids,in the system research process of anti-P.aeruginosa fraction from the leaves of Dracontomelon dao.This work could promote the further clarity of chemical substance basis.The anti-P.aeruginosa evaluation results demonstrated that luteolin,quercetin,quercetin3-O-?-glucopyranosideandquercetin3-O-?-galactopyranoside were the activial antibacterial compounds in the flavonoids.The entire research was the foundation of the intense research to the leaves of Dracontomelon dao and the development of new types of antimicrobial drug.