Synthesis And Biological Activity Of Nitrogen-containing Heterocyclic Myricetin Derivatives

As a kind of polyhydroxy flavonoid compound,Myricetin have bactericidal,anti-cancer,anti-virus and other characteristics widespread activities and pharmacological effects.1,2,4-Triazole Schiff base containing a triazole functional group triazole ring and a Schiff base functional group imine active fragment,therefore it exhibits a broad spectrum of biological activity,such as bacteriostatic,anti-virus and weeding.Quinoxaline is a class of aromatic benzopyrazine heterocyclic compounds,which has various biological activities such as bacteriostatic,anticancer and antiviral,considering these above findings.In this thesis,1,2,4-triazole Schiff base myricetin derivatives A series(A₁-A₂₃)and myricetin quinoxaline group derivatives B series(B₁-B₁₆)was designed and synthesized with the myricetin as lead compound.The all target compounds were characterized by ¹H NMR,¹³C NMR and HRMS.Following the antibacterial and antiviral activities were tested.Antibacterial activity of the target compounds was tested by turbidity method,the experimental results showed that the EC₅₀ values of compounds A₆,A₉,A₁₇,B₁₅,B₁₆ against Xac were 9.9,9.4,8.8,11.2,11.8μg/mL,respectively,which were superior to those of Bismerthiazol（54.9μg/mL）.The EC₅₀ values of compound A₂₃against Rs was 15.5μg/mL better than Bismerthiazol（55.2μg/mL）.The EC₅₀ values of compounds A₁,B₆ against Xoo were 47.1 and 34.5μg/mL,better than control drug Bismerthiazol（148.2μg/mL）.The results of observation of the target compound A₁₇ on Xac by scanning electron microscopy（SEM）showed the antibacterial mechanism of this compound against Xac may be through destroying the cell membrane structure of bacteria,leading to the incomplete structure of bacteria,further achieving the purpose of inhibition.Anti-plant viral activity of the targets compounds was tested by half-leaf method,the results showed the curative activity inhibitory rate of compounds A₇,A₁₀,B₇,B₁₃against TMV were 52.5,52.4,51.6,51.4%,respectively,closing to Ninnanmycin（52.7%）with the test concentration of 500μg/mL.The protective activity inhibitory rate of compounds A₆,A₂₃,B₇,B₁₃ against TMV were 58.7,58.0,59.8,62.3%,respectively,nearing Ninnanmycin（65.7%）.The inactivation activity inhibitory rate of compounds A₇,B₁₁ against TMV were 88.6,79.6%,respectively,which were close to Ninnanmycin（90.4%）.