表没食子儿茶素没食子酸酯全乙酰化衍生物的合成及急性毒性试验

目的 合成表没食子儿茶素没食子酸酯(EGCG)的全乙酰化衍生物(AcEGCG),并研究EGCG和AcEGCG对小鼠的急性毒性作用.方法 EGCG为反应底物,乙酸酐为酰化剂,吡啶为催化剂,在乙酸乙酯中反应过夜,反应液经酸洗、碱洗及水洗后干燥得到AcEGCG,高效液相色谱法(HPLC)检测其纯度,1H-NMR和13C-NMR鉴定其结构.取昆明种小白鼠,灌胃给药,连续14 d观察其急性毒性症状.采用改进寇氏法计算半数致死量(LD50).结果 合成的EGCG乙酰化衍生物经1H-NMR和13C-NMR鉴定为AcEGCG,HPLC测定纯度为99%.EGCG组小鼠给药后第1～5天出现死亡,中毒表现开始为多动,不安定,随后缩成一团,嗜睡,呼吸急促,最后痉挛,死亡.LD50=761.5 mg/kg.AcEGCG组小鼠无死亡,病理检查与正常对照组无差异.最大耐受量为8 300 mg/kg.结论 EGCG有一定的毒性,而AcEGCG无明显毒性反应.

Study on the Synthesis of (-)-Epigallocatechin Gallate Peracetylated Derivative and Its Acute Toxicity Test

Objective To study the synthesis of(-)-Epigallocatechin gallate(EGCG) peracetylated derivative(AcEGCG) and the acute toxicity of EGCG and AcEGCG in mice.Methods In order to synthesize AcEGCG,EGCG was treated with ethyl acetate overnight using acetic anhydride as acylating agent and pyridine as catalyst.The resulting liquid was treated with 0.5% of HCl,4% of NaHCO3 and distilled water,and the desired product could be got after drying.The purity of AcEGCG was detected by high performance liquid chromatography(HPLC),and confirmed by 1H-NMR and 13C-NMR.Intragastric administration was adopted in Kunming mice,and the toxicity effect of AcEGCG and EGCG in mice was observed for 14 days after the administration.LD50 was calculated by improved Kou′s method.Results The structure of AcEGCG was confirmed by 1H-NMR and 13C-NMR,and its purity was 99% determined by HPLC.The mice in EGCG group were found to be dead 1-5 days after the administration.Before their death,the poisoning mice appeared to be hyperactivity,unstable at beginning,then curled,lethargy,shortness of breath,and spasm.LD50 of EGCG was 761.5 mg/kg.No dead mice were found in AcEGCG group,and there was no significant difference in the results of pathological examination between AcEGCG group and the normal controls.Maximum tolerated dose(MTD) of AcEGCG was 8 300 mg/kg.Conclusion EGCG is of certain toxicity,while AcEGCG has no obvious toxicity.