ABSTRACT

Epigallocatechin gallate (EGCG), the main polyphenolic substance in tea, exhibits well-known biological benefits. In order to improve fat solubility and bioavailability, a novel path for the lipase enzymatic transesterification synthesis of acylated EGCG derivatives in an ionic liquid solvent was established. The optimal reaction parameters were determined and a maximum conversion of the transesterification reaction was achieved at 98.65%. [Bmim][BF₄] was the best reaction medium and the immobilized lipase Novozym 435 was the best catalyst. The enzyme was added to a final concentration of 2% (w/w, EGCG), and the reaction was performed at an optimum temperature of 70°C stirring for 10 h at 250 rpm. The most suitable acyl donor, vinyl acetate, and EGCG were mixed at a molar ratio of 90:1 for the reaction. The structure of the purified acetylated EGCG was determined to be 5″-O-acetyl-EGCG and 3″, 5″-2-O-acetyl-EGCG by mass spectrometry, NMR, and infrared analyses.

摘要

茶中的主要多酚物质表没食子儿茶素没食子酸酯（EGCG）具有众所周知的生物学益处。为了提高脂肪的溶解度和生物利用度，建立了在离子液体溶剂中脂化酶EGCG衍生物的脂肪酶酶促酯交换合成的新途径。确定了最佳反应参数，酯交换反应的最大转化率达到98.65％。[Bmim] [BF ₄]是最好的反应介质，固定化的脂肪酶Novozym 435是最好的催化剂。加入酶至终浓度为2％（w / w，EGCG），并且反应在70℃的最佳温度下以250rpm搅拌10h进行。将最合适的酰基供体，乙酸乙烯酯和EGCG以90：1的摩尔比混合进行反应。通过质谱，NMR和红外分析确定纯化的乙酰化EGCG的结构为5″ -O-乙酰基-EGCG和3″，5″ -2 - O-乙酰基-EGCG。