L-抗坏血酸没食子酸酯的酶催化合成及抗氧化性

Lipase-catalyzed synthesis and antioxidant activity of L-ascorbyl gallate

以没食子酸和L-抗坏血酸为原料,在固定化脂肪酶Novozym 435催化下合成了L-抗坏血酸没食子酸酯,并测试了其抗氧化活性。结果表明,在没食子酸10 mmol,L-抗坏血酸20 mmol,脂肪酶0.25 g,环己酮20 mL,50℃反应24 h的条件下,没食子酸转化率达82.7%。抗氧化性试验表明,L-抗坏血酸没食子酸酯可以有效清除DPPH自由基和羟基自由基,其IC50分别为9.97μmol/L和2.45 mmol/L,而L-抗坏血酸清除DPPH自由基和羟基自由基的IC50分别为23.55μmol/L和5.14 mmol/L,抗氧化活性明显好于L-抗坏血酸。

L-Ascorbyl Gallate was synthesized from gallic acid and L-ascorbic acid catalyzed by Novozym435 li- pase, and its antioxidant activity was determined. The results showed that the conversion rate of gallic acid was up to 82.7% under the condition of gallic acid 10 mmol, L-ascorbic acid 20 mmol, lipase 0. 25 g, cyclohexanone 20 mL, 50℃ and 24 h. The antioxidant tests indicated that L-ascorbyl gallate could efficiently scavenge DPPH radical and hydroxyl radical. The IC50 of L-ascorbyl gallate to DPPH radical and hydroxyl radical were 9.97 μmol/L and 2.45 mmol/L, and IC50 of L-ascorbic acid to DPPH radical and hydroxyl radical were 23.55 μmol/L and 5.14 mmol/L. The antioxidant activity of L-ascorbyl gallate was significantly higher than that of L-ascorbic acid.