| OBJECTIVE:This paper explored the chemical composition of ethyl acetate part of Dracontomelon dao leaf,evaluated the antibacterial effect of the ethyl acetate part of Dracontomelon dao leaf and the interaction between flavonoid and explored the antibacterial mechanism of the sample of ethyl acetate extractive of Dracontomelon dao leaf.METHOD:This paper comprehensively analyzed the chemical substances in the ethyl acetate part of Dracontomelon dao leaf using LC-MS technology and database comparison technology,and determined the content of cianidanol,epicatechin,luteolin,and quercetin by UPLC.We determined the inhibitory action of E.coli in the ethyl acetate part of Dracontomelon dao leaf using a combination of microcalorimetry and general rotary unitized design.And we got the mathematical function between the flavonoid content and the antibacterial effect.We established a mathematical model of the antibacterial activity and interaction of four flavonoids to explored the antibacterial effects of flavonoids and their interactions.This paper explored the mechanism of interfering with intracellular metabolism of E.coli from Dracontomelon dao leaf using UPLC/Q-TOF mass spectrometry.RESULT:?1?Chemical substances in the ethyl acetate part of Dracontomelon dao leafThis paper found that there are 214 high-content compounds in the S1 sample,248high-content compounds in the S2 sample,and 196 high-content compounds in the S3sample.It was found that there were 42 high-level substances in the three samples by comparison,including flavonoids such as catechin,epicatechin,luteolin,and quercetin.Among them,the content of quercetin in S1 sample was 7.018?g·mg-1,the content of epicatechin was 0.916?g·mg-1,the content of cianidanol was 28.319?g·mg-1,and the content of luteolin was 0.796?g·mg-1.The content of quercetin in S2 sample was141.112?g·mg-1,the content of epicatechin was 6.023?g·mg-1,the content of cianidanol was 297.039?g·mg-1,and the content of luteolin was 17.964?g·mg-1.The content of quercetin in S3 sample was 78.417?g·mg-1,the content of epicatechin was4.426?g·mg-1,the content of cianidanol was 338.201?g·mg-1,and the content of luteolin was 1.655?g·mg-1.?2?Mathematical model of antibacterial activity and interaction of flavonoids in Dracontomelon dao leaf.The paper was based on the content of flavonoids in the S2 sample of the ethyl acetate part of Dracontomelon dao leaf,which it was the best inhibition effect to E.coli.Microcalorimetry was the main technique for determining the antibacterial effect of drugs.We got a mathematical model using a general rotary unitized design program,and established a regression equation,which is the mathematical function between catechin,epicatechin,quercetin,luteolin and antibacterial rate.The antibacterial activity of flavonoids was found to be in order of:luteolin,cianidanol,quercetin,and epicatechin in result of variance analysis and single factor effect analysis.There was a clear synergy between luteolin and cianidanol,luteolin and quercetin in the two-factor interaction analysis result.?3?The mechanism of Dracontomelon dao leaf affecting intracellular metabolism of E.coliThis paper explored E.coli intracellular metabolites using low-temperature quenching and organic solvent extraction and UHPLC/Q-TOF high-resolution mass spectrometry techniques,and screening specific biomarkers using principal component analysis?PCA?or partial least squares-discriminant analysis?OPLS-DA?.There were27?S1 sample group?,29?S2 sample group?,and 32?S3 sample group?metabolites with significant differences.It belongs to phospholipid compounds,fatty acid compounds,glyceride compounds,arachidonic acid compounds,and sugar compounds.The major pathways affected were sphingolipid metabolism,arachidonic acid metabolism,?-linolenic acid metabolism,and glycerophospholipid metabolism?S3treatment group only?.CONCLUSION:This paper identified the content of chemical substances and four flavonoids in the ethyl acetate part of Dracontomelon dao leaf.And the mathematical model was established to examine the antibacterial effects and interactions of the samples and flavonoid monomers from the ethyl acetate part of the Dracontomelon dao leaf.This paper explored the antibacterial mechanism of human facial acetate ethyl acetate sample using metabolomics techniques.It lays a solid foundation for the future development of quality standards for Dracontomelon dao leaf and comprehensive antibacterial effects. |
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