儿茶素-稀土配合物的合成、表征及抗菌活性

Synthesis, Characterization, and Antibacterial Activity of Rare Earth-Catechin Complexes

以稀土(Re^(3+))和儿茶素(C)为原料,由液相合成法制备了3种(La^(3+)-C、Gd^(3+)-C、Er^(3+)-C)配合物,结合傅里叶变换红外光谱、紫外光谱、X射线光电子能谱及配位数测定对配合物结构进行表征,确定了配合物的配位数为8。并采用牛津杯法、最小抑菌浓度(MIC)及最小杀菌浓度(MBC)等三种方法测定了Re^(3+)-C对大肠杆菌、金黄色葡萄球菌、绿脓杆菌、沙门氏菌4种食源性细菌的抗菌性能。结果表明,这3种稀土配合物对各试验菌株均表现不同程度的抑制能力,相较Re^(3+)和C而言,Re^(3+)-C配合物的抑菌性能均有显著的提高。Re^(3+)-C的抑菌活性顺序为:Gd^(3+)-C>La^(3+)-C>Er^(3+)-C,其中Gd^(3+)-C对4种细菌的MIC值分别为:1.550、0.097、0.780、1.550μmol·m L^(-1),MBC值分别为3.100、0.194、1.550、1.550μmol·m L^(-1),Gd^(3+)-C对金黄色葡萄球菌表现出最佳的抑菌和杀菌能力。

Three kinds of novel coordination compounds [Re^3＋-C] （Re = La, Gd, Er; C = Catechin） were synthesized by the liquid-phase method, and characterized by Fourier transform infrared （FT-IR） spectroscopy, ultraviolet-visible （UV） spectrophotornetry, X-ray photoelectron spectroscopy （XPS）, and coordination number determination. The results indicated that the coordination number of the complexes is 8. Moreover, the antibacterial activities of Re^3＋-C against Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Salmonella were evaluated by the Oxford cup, minimum inhibition concentration （MIC）, and minimum bactericidal concentration （MBC） approaches. Compared with Re3＋ and C, the as-prepared complexes exhibited excellent antimicrobial activity toward the four strains. The MIC of Gd^3＋-C to these food-borne bacteria was 1.550, 0.0968, 0.775, and 1.550μmol·mL-1, respectively, while the corresponding MBC values were 3.100, 0.194, 1.550, and 1.550μmol·mL^-1. It is clear that the Gd^3＋-C complex showed the best antibacterial and germicidal activity against S. aureus.