| Flavonoids,as an important class of natural organic compounds,have a br oad spectrum of physiological activities and are widely distributed in nature.H owever,the shortcomings of such compounds are also obvious:poor solubility,and more sites of action,lack of specificity and selectivity for some diseases.Reasons such as these limit their medicinal development.If the flavonoids are used as the parent,structural modifications are made to study the structure-acti vity relationship between the structure and its activity.Through activity optimiz ation,it is possible to find derivatives with better activity and medicinal devel opment prospects.In this paper,2,6-dihydroxyacetophenone,o-fluorobenzoyl chloride,m-fluor obenzoyl chloride and p-fluorobenzoyl chloride were used as raw materials to s ynthesize 6 fluoroflavonoid derivatives;6 flavonoid derivatives A ring The 5-po sition hydroxyl group was structurally modified to synthesize 192 esterified deri vatives.Of the synthesized compounds,194 are new compounds.The structure was characterized by nuclear magnetic resonance（NMR）spectroscopy and mass spectrometry（ESI-MS）.The antibacterial activity of the synthesized compounds against six kinds of bacteria such as Erwinia carotovora,Bacillus cereus,P.syingae pv.actinidiae,Bacillus subtilis,Escherichia coli and Staphylococcus aureus was determined by disk diffusion method.The results showed that all the compounds showed no activity against Bacillus cereus,Bacillus subtilis,Escherichia coli and Staphylococcus aureus;some compounds had strong antibacterial activity against the Erwinia carotovora and P.syingae pv.actinidiae.When the amount was 50μg/tablet,the diameter of the inhibition zone was 13.0-20.5 mm.The inhibitory activities of all compounds against Valsa mali Miyabe et Yamada were determined by mycelial growth rate method.Compounds C-03 and D-11 showed good activity with EC50 of 222.269μg/mL and 83.675μg/mL,respectively.The apple shoots in vivo test determined the effect of compound D11 on apple rot disease.Apple shoots had good protective effect.When the concentration of compound was 400μg/mL,the inhibition rate of apple rot disease was 67.7%. |
