Abstract: | Objective Synthesize aloeemodin-manganese (Ⅱ), aloeemodin-iron (Ⅲ), and aloeemodin-cobalt (Ⅱ) complexes and characterize their structures, and then compare the antibacterial activity of ligands and complexes. Methods Aloeemodin was used as the raw material, and aloeemodin-manganese (Ⅱ), aloeemodin-iron (Ⅲ), and aloeemodin-cobalt (Ⅱ) complexes were synthesized by dissolving in absolute ethanolandstirring. Then, the nuclear magnetic resonance proton spectroscopy, coordination titration, infrared spectroscopy, thermogravimetric-differential thermal analysis, andultraviolet spectroscopy were used to characterize their structures. The filter paper test method and the double dilution method were used to compare the inhibitory effects of ligands and complexes on three bacteria, including E. coli, Staphylococcus aureus, and Streptococcus pneumoniae. Results The ligands and complexes had different degrees of inhibition on E. coli, Staphylococcus aureus, and Streptococcus pneumoniae, and most of complexes had stronger antibacterial activity than their ligands. Conclusion The coordination of aloeemodin and metal ions produced a synergistic antibacterial effect. |