Synthesis, Antimicrobial Activity And Antimicrobial Mechanism Of 2-acetylpyridine Thiosemicarbazone And Their Metal Complexes

Researcher found that containing heterocyclic thiosemicarbazone ligands and their metal complexes have much better antimicrobial activity than general thiosemicarbazone ligands. The introduction of heterocyclic to change its structure, in order to obtain compounds with better antimicrobial activity. Acetylpyridine thiosemicarbazone as containing heterocyclic compounds, which has been widely studied, is a class of compounds with potential biological activity. In addition, a variety of thiosemicarbazone compounds, biological activity tests showed that, the introduction of different active groups in the N(4) position .The antimicrobial activity and anti-cancer activity of their can be increased. Various studies found that Mn, Ni, Co and other metal effects thiosemicarbazone ligands biological activity. Therefore, the synthesis of different structures of thiosemicarbazone ligands and their metal complexes, testing their antimicrobial activity, has important theoretical significance and practical value.We have synthesized acetylpyridine thiosemicarbazone ligandsHL1,acetyl pyridine-N(4)-phenyl thiosemicarbazone ligandsHL2,acetylpyridine-N(4)- Methylmalonic thiosemicarbazone ligand HL³ and HL⁴ , acetylpyridine S-methyldithiocarbazate HL⁴ and their metal complexes-Mn(L¹)₂(1), Ni(L²)₂(2) ,Mn(L³)₂ (3),Ni(L³)₂(4) and Co(L⁴)₂ (Scheme 1), Analyzed C, H, N elemental By Perkin-Elmer 240C Element Analytical Instruments. Testing antimicrobial activity of ligands and complexes, the results show that: they are activity against all strains, including bacterial and fungi .Which the strongest is ligand HL3, followed by ligands HL¹, HL² ligand is weakest .They are more sensitive on the Pseudomonas aeruginosa and Bacillus subtilis. Studying on the antibacterial mechanisms through determination the cell growth curve, SDS-PAGE electrophoresis, scanning electron microscopy .The results show that the mechanism of Pseudomonas aeruginosa may be related to synthesis of protein and block cell division and growth .The mechanism of Bacillus subtilis may block cell division and growth, destroy cell structure, leakage of its contents lead to death .