几种咖啡酸酯类衍生物对桑丁香假单胞菌的抑制活性鉴定

Identification on Inhibition Activity of Several Caffeic Acid Alkyl Ester Derivatives Against Pseudomonas syringae pv. mori

咖啡酸是一类具有多种生物活性的物质,尤其是抑菌活性被应用于农作物病害防治。以天然咖啡酸为先导化合物合成8种咖啡酸酯类衍生物,采用平板扩散法测试咖啡酸及其酯类衍生物对桑疫病病原菌桑丁香假单胞菌Pseudomonas syringae pv.mori的抑菌活性,结果表明:咖啡酸、咖啡酸甲酯、咖啡酸乙酯、咖啡酸丙酯和咖啡酸异丙酯对桑丁香假单胞菌、大肠杆菌Escherichia coli(CK)无抑制作用;而咖啡酸丁酯、咖啡酸戊酯、咖啡酸己酯和咖啡酸苯乙酯对桑丁香假单胞菌与大肠杆菌均有抑制作用,其中咖啡酸丁酯、咖啡酸苯乙酯对桑丁香假单胞菌有较强的抑制活性,抑菌圈直径>1.0 cm。进一步通过分光光度法检测初筛有抑菌活性的4种咖啡酸酯类衍生物对桑丁香假单胞菌的MIC_(50)值和MIC_(90)值,抑菌活性由强到弱依次为咖啡酸戊酯、咖啡酸丁酯、咖啡酸苯乙酯、咖啡酸己酯。试验结果提示,初筛的4种咖啡酸酯类衍生物具有开发为桑疫病防治专用抑菌剂的潜力。

Caffeic acid is a kind of material that has a variety of biological activities. It was applied in crop disease control for its bacteriostasis. With the natural caffeic acid as lead compound,eighty caffeic acid alkyl ester derivatives were synthesized and their antimicrobial activities against Pseudomonas syringae pv. mori causing mulberry bacterial blight were evaluated by agar plate diffusion method. The results showed that caffeic acid,methyl caffeate,ethyl caffeate,propyl caffeate and isopropyl caffeate had almost no antibacterial activity against P. syringae pv. mori and E. coli. Butyl caffeate,amyl caffeate,hexyl caffeate and caffeic acid phenethyl ester showed antibacterial activities against P. syringae pv. mori and E. coli. Butyl caffeate and caffeic acid phenethyl ester had strong antimicrobial activity against P. syringae pv. mori（ the inhibition zone diameter was higher than 1. 0 cm）. The inhibition rate of four caffeic acid alkyl ester derivatives that showed antibacterial activity in primary screening test was further evaluated by spectrophotometry method. According to MIC_（50） and MIC_（90） value to P. syringae pv. mori,the antibacterial activity was in the order of amyl caffeate butyl caffeate caffeic acid phenethyl ester hexyl caffeate. Thus,the preliminarily screened four caffeic acid alkyl ester derivatives have the potential to be developed into specialized antibacterial agents for controlling mulberry bacterial blight.