肉桂酸薄荷酯的合成及抑菌活性研究

Synthesis and antimicrobial of menthyl cinnamate

为开发新型凉味剂,以肉桂酸与亚硫酰氯为原料,制得肉桂甲酰氯;肉桂酰氯在二氯甲烷和无水吡啶条件下与L-薄荷醇反应,一锅法制得肉桂酸薄荷酯,得率83.79%。并通过~1H NMR、^(13)C NMR和HRMS对目标化合物进行结构表征。同时,对肉桂酸薄荷酯的凉感阈值和持久性进行生理评价,结果表明凉感阈值为1.21 mg/L,薄荷醇浓度为100 mg/L浸渍的滤片凉感持续时间在(24~27)min;并以左氧氟沙星为阳性对照,分别采用滤纸片法和平板连续稀释法测定肉桂酸薄荷酯对6种供试菌株的抑菌圈直径及最小抑菌浓度(MIC),其对大肠杆菌和黑曲霉具有较强的抑菌作用,抑菌圈直径分别为17.6 mm和15.4 mm,MIC为1.17μg/m L和2.34μg/m L。结果证明,肉桂酸薄荷酯对于所选的病原菌都有很好的抗菌活性。

For the development of new cooling agents, cinnamic acid and thionyl chloride were used as starting materials to prepare cinnamoyl chloride. Then, menthyl cinnamate was prepared via the reaction of the cinnamoyl chloride and menthol, with methylene chloride as solvent and anhydrous pyridine as acid binding agent, and the yield achieved 83.79%. In addition, the synthesize compouds were charcaterized by 1H NMR, 13C NMR and HRMS spectra. The targeted product shows good cool feeling and its threshold value achieves 1.21 mg/L. A filter paper strip impregnated with 100 mg/L solution of the targeted product could maintain cool feeling in mouth for （24-27）min. The filtering paper method and plate dilution method were used for determining inhibition zone diameter and minimum inhibitory concentration （MIC） of menthyl cinnamate against six tested strains, respectively, with levofloxacin as positive control. Furthermore, the menthyl cinnamate showed strong antibacterial activity against Escherichia coli and Aspergillus niger, and their inhibition zone diameters were 17.6 mm and 15.4 mm, and the MIC were 1.17 lag/mL and 2.34 lag/mL, respectively. The results demonstrated that menthyl cinnamate for the selected pathogens have a very good antibacterial activity.