非水相酶促合成不同链长的对香豆酸酯及其自由基清除能力

Enzymatic Synthesis of Different Chain Lengths of Coumarate and Capacity of Scavenging Radical

酶促酯交换反应常用于改善酚酸的亲脂性。本研究采用酶促酯交换策略,将脂肪酸链以羧基的形式引入对香豆酸中,成功地在非水介质中合成了一系列新的对香豆酸衍生物。在最佳反应条件下,脂肪酶Nov.43540 mg/mL,溶剂为吡啶:环己烷=1:9,底物摩尔比=1:10,温度50℃,转速180 r/min,对香豆酸甲酯的转化率可达98%。进一步的研究表明,20μM时p-CA对DPPH自由基(醇溶体系)的清除活性为56.34%,对香豆酸月桂酯、对香豆酸癸酯、对香豆酸辛酯、对香豆酸己酯、对香豆酸丁酯和TBHQ在相同浓度下对DPPH自由基的清除活性分别为73.91%、70.32%、68.90%、60.62%、43.65%和67.51%。其中,对香豆酸月桂酯的DPPH自由基清除活性明显高于p-CA和TBHQ,但低于Trolox。结论:非水相酶促合成的不同链长对香豆酸酯具有良好的清除自由基能力。因此,合成的具有不同抗氧化活性的酯类衍生物有望应用于不同的食品、药物和化妆品体系中,为酯类衍生物的合成提供有益的指导。

Enzymatic transesterification is often used to improve the lipophilicity of phenolic acids.In this study,a series of new derivatives of p-coumaric acid were successfully synthesized in non-aqueous medium by introducing fatty acid chain into p-coumaric acid in the form of carboxyl group by enzymatic transesterification strategy.Under the optimal reaction conditions:the lipase NOV.435 of 40 mg/mL,the solvent of pyridine:cyclohexane of 1:9,the molar ratio of substrate of 1:10,temperature of 50℃,the rotation speed of 180 r/min,the conversion rate was reached to 98%.In addition,further study showed that the scavenging activity of p-Ca against DPPH radical(alcohol-soluble system)was 56.34%at 20μM,and the scavenging activity against DPPH radical of lauryl coumarate,p-decyl coumarate,p-octyl coumarate,p-hexyl coumarate,p-butyl coumarate and TBHQ at the same concentration was 73.91%,70.32%,68.90%,60.62%,43.65%and 67.51%,respectively.Obviously,the scavenging activity of laurel ester against coumarate was higher than those of p-Ca and TBHQ.Conclusion:coumarate has good free radical scavenging ability by enzymatic synthesis of different chain lengths in non-aqueous phase.Therefore,the synthesized ester derivatives with different antioxidant activities will be expected to be used in different food,drug and cosmetic systems,and provide beneficial guidance for the synthesis of ester derivatives.