title: Effect of ionic liquids on enzymatic synthesis of caffeic acid phenethyl ester.
abstract: Although caffeic acid phenethyl ester (CAPE), an active flavonoid, plays an important role in the antioxidant activity of honeybee propolis, the isolation of CAPE from honeybee propolis is time-consuming due to wide variety of impurities present. Therefore, biochemical method to synthesize CAPE was investigated in this study. Since ionic liquids (ILs) possess some unique characteristics as appreciated alternatives to conventional solvents for certain biotransformation, the effect of ILs as reaction media for enzymatic synthesis of CAPE was assessed. Several factors including substrate molar ratio, and reaction temperature affecting the conversion yield of lipase-catalyzed CAPE synthesis were also investigated. Reaction yields were significantly higher in hydrophobic ILs than in hydrophilic ILs (almost zero). Among nine hydrophobic ILs tested, the highest conversion of synthetic reaction was obtained in 1-ethyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide ([Emim][Tf(2)N]). A reaction temperature of 70 °C was found to give high conversion. In addition, optimal substrate molar ratio between phenethyl alcohol and caffeic acid (CA) was decreased significantly from 92:1 to 30:1 when ILs were used instead of isooctane.
authors: Department of Chemical Engineering and Nano-Bio Technology, Hannam University, Daejeon, 305-811, Korea. shha@hnu.kr
authors: Sung Ho
authors: SH
authors: Ha
authors: Tran Van
authors: TV
authors: Anh
authors: Sang Hyun
authors: SH
authors: Lee
authors: Yoon-Mo
authors: YM
authors: Koo
mesh_terms: D002109:Caffeic Acids / Q000138:chemical synthesis*; D004789:Enzyme Activation; D052578:Ionic Liquids / Q000737:chemistry*; D008049:Lipase / Q000737:chemistry*; D010626:Phenylethyl Alcohol / Q000031:analogs & derivatives* / Q000138:chemical synthesis
chemical_list: D002109:Caffeic Acids; D052578:Ionic Liquids; D008049:Lipase; C055494:caffeic acid phenethyl ester; D010626:Phenylethyl Alcohol