绿原酸的提取及稀土配合物抗菌活性测定

Study on Extraction of Chlorogenic Acid and Determination of Antibacterial Activity of Its Rare-earth Complexes

以乙酸乙酯和0.05mol/LHCl组成的混合溶液作萃取剂,从金银花中一步提取绿原酸。研究了乙酸乙酯体积分数、温度、浸取时间对提取绿原酸的影响。并用绿原酸与LaCl3.6H2O反应合成了绿原酸合镧(Ⅲ)配合物,通过元素分析、红外光谱、热重分析和化学分析,确定配合物的组成为:[La(C16H17O9)3].2H2O。测试了配体和配合物分别对革兰氏阴性菌(大肠杆菌)和革兰氏阳性菌(金黄色葡萄球菌)的抗菌活性。实验结果表明,提取绿原酸最佳实验条件是:温度65℃,乙酸乙酯体积分数80%,浸取时间3h。提取物相对原料量的质量分数为3.21%,绿原酸的质量分数86.3%;绿原酸抗金黄色葡萄球菌的活性比抗大肠杆菌强。配合物对大肠杆菌的抗菌活性比配体明显增强,但对金黄色葡萄球菌的抗菌活性反而比配体弱。

Chlorogenic acid is extracted from Lonicera japonica Thunb. directly with extractant which is composed of ethyl acetate and hydrochloric acid （0.05 mol/L） , and the effects of volume fraction of ethyl acetate, temperature and leaching time on extraction are investigated. The complex of [ La^3＋] is synthesized by the reaction of chlorogenic acid with LaCl3 ·6H2O, and the confirmed complex structure is [La（ C16H17O9 ）3 ]·2H2O by elemental microanalysis, infrared spectroscopy（IR）, and thermogravimetry analysis （TG）. Moreover, the antibiotic activities of ligand and complex against Gram-negative bacteria and Grampositive bacteria are also tested. The results show： that the optimum condition of extaction of chlorogenic acid is： temperature 65℃, volume fraction of ethyl acetate 80 %, leaching time 3 h, mass ratio of extracting substances to lonicerae flos 3.21% , and mass fraction of chlorogenic acid 86.3 % ;The antibacterial activity of chlorogenic acid against Staphylococcus aureus is stronger than Escheria coli. The antibacterial activity of the complex against E. coli is evidently stronger than that of the ligand. In contrast, antibacterial activity of the complexes against S. aureus is weaker than that of the ligand.