EGCG乙酰化分子修饰取代度影响因素分析

为改善表没食子儿茶素没食子酸酯(epigallocatechin gallate,EGCG)的脂溶性和生物利用度,在乙酸乙酯体系中化学合成乙酰化EGCG。研究酰基供体乙酸酐用量、催化剂吡啶用量、溶剂乙酸乙酯用量、反应温度、反应时间对EGCG乙酰化分子修饰取代度的影响。结果表明,以0.19 g的EGCG为原料,乙酸酐用量0.04 m L、吡啶用量0.02 m L、乙酸乙酯用量20~60 m L、反应温度20~25℃、反应时间1~3 h有利于1~3取代度乙酰化EGCG生成;乙酸酐用量0.12~0.20 m L、吡啶用量0.06~0.20 m L、乙酸乙酯用量10~20 m L、反应温度17~25℃、反应时间5~9 h有利于4~6取代度乙酰化EGCG生成;乙酸酐用量0.40~0.80 m L、吡啶用量0.10~0.20 m L、乙酸乙酯用量5~10 m L、反应温度25~40℃、反应时间5~9 h有利于7~8取代度乙酰化EGCG生成。

Major Factors Affecting Substitution Degree of Acetylated EGCG

Acetylated epigallocatechin gallate (EGCG) was chemically synthesized in ethyl acetate solvent system for improving the lipid solubility and bioavailability of EGCG. The effects of acetyl anhydride dosage, catalyst pyridine dosage, ethyl acetate dosage, reaction temperature and reaction time on the substitution degree of acetylated EGCG were studied. As a result, it was found that 0.04 mL of acetic anhydride, 0.02 mL of pyridine, 20–60 mL of ethyl acetate, a reaction temperature of 20–25 ℃ and a reaction time of 1–3 h were optimal for the synthesis of acetylated EGCG with a degree of substitution in the range from 1 to 3 from 0.19 g of EGCG. The optimal synthesis conditions for EGCG acetylation that provided a substitution degree between 4 and 6 were 0.12–0.20 mL of acetic anhydride, 0.06–0.20 mL of pyridine, 10–20 mL of ethyl acetate, a reaction temperature of 17–25 ℃, and a reaction duration of 5–9 h, while those for a substitution degree of 7–8 were 0.40–0.80 mL of acetic anhydride, 0.01–0.20 mL of pyridine, 5–10 mL of ethyl acetate, a reaction temperature of 25–40 ℃, and a reaction duration of 5–9 h.