Katsoura M H, Polydera A C, Tsironis L, Tselepis A D, Stamatis H
Laboratory of Biotechnology, Department of Biological Applications and Technologies, University of Ioannina, 45110 Ioannina, Greece.
J Biotechnol. 2006 Jun 10;123(4):491-503. doi: 10.1016/j.jbiotec.2005.12.022. Epub 2006 Feb 2.
Biocatalytic preparation of acylated derivatives of flavonoid glycosides was performed using various immobilized lipases in two different ionic liquids, namely 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim]BF(4)) and 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim]PF(6)). The influence of various reaction parameters on the performance and the regioselectivity of the biocatalytic process was pointed out, using as model reaction the acylation of naringin and rutin with vinyl butyrate, catalyzed by immobilized Candida antarctica lipase at 60 degrees C. The biocatalytic modification of flavonoids strongly depended on the ionic liquid used, the molar ratio of substrates, as well as the acyl donor chain length. The highest conversion yield (about 65% after 96 h of incubation) was obtained with short chain acyl donors (up to four carbon atoms), at a relatively high molar ratio (10-15) in both ionic liquids used. The amount of monoacylated flavonoid derivatives produced in a single-step biocatalytic process in [bmim]BF(4) was up to 5.5 g/L for monoacylated rutin and 30 g/L for monoacylated naringin. The regioselectivity of the process was higher in [bmim]BF(4) than in [bmim]PF(6) or organic solvents. Reaction rates observed in ionic liquids were up to four times higher than those reported for organic media. The acylation of sugar moiety of rutin with various acyl donors affected its antioxidant potential towards both isolated LDL and total serum model in vitro. A significant increase of antioxidant activity was observed for rutin-4'''-O-oleate.
使用多种固定化脂肪酶在两种不同的离子液体中进行类黄酮糖苷酰化衍生物的生物催化制备，这两种离子液体分别是1-丁基-3-甲基咪唑四氟硼酸盐（[bmim]BF₄）和1-丁基-3-甲基咪唑六氟磷酸盐（[bmim]PF₆）。以固定化南极假丝酵母脂肪酶在60℃催化柚皮苷和芦丁与丁酸乙烯酯的酰化反应作为模型反应，指出了各种反应参数对生物催化过程的性能和区域选择性的影响。类黄酮的生物催化修饰强烈依赖于所使用的离子液体、底物的摩尔比以及酰基供体链长。在两种使用的离子液体中，以相对较高的摩尔比（10 - 15）使用短链酰基供体（最多四个碳原子）时，可获得最高转化率（孵育96小时后约65%）。在[bmim]BF₄中一步生物催化过程中产生的单酰化类黄酮衍生物的量，单酰化芦丁高达5.5 g/L，单酰化柚皮苷高达30 g/L。该过程在[bmim]BF₄中的区域选择性高于在[bmim]PF₆或有机溶剂中的区域选择性。在离子液体中观察到的反应速率比有机介质中报道的反应速率高多达四倍。芦丁糖部分与各种酰基供体的酰化影响了其对体外分离的低密度脂蛋白和全血清模型的抗氧化潜力。对于芦丁-4'''-O-油酸酯，观察到抗氧化活性显著增加。
