Antibacterial and antifungal activity of zinc(II) complexes with some 2-methylbenzimidazole derivatives

Zinc(II) chloride reacts with 2-methylbenzimidazole derivatives to give complexes of the formula ZnL2Cl2-nH2O, where L=2-methylbenzimidazole l-benzyl-2-methylbenzimida-zole and l-(4-methylbenzyl)-2-methylbenzimidazole n=0, 0.5 or 1. All the ligands and their zinc(II) complexes were evaluated for their in vitro antimicrobial activity against Pseudomonas aeruginosa Bacillus sp., Staphylococcus aureus, Sarcina lutea and Candida pseudotropicalis. It was found that the majority of the investigated compounds displayed in vitro antimicrobial activity against very persistent microorganisms, except for the starting ligand, 2-methylbenzimidazole and its zinc(II) complex which were active only against gram-negative bacteria. None of the compounds was significantly effective against Candida pseudotropicalis, except for l-(4-methylbenzyl)-2-methylbenzimidazoleandits complex, which very slightly or slightly inhibited the yeast growth. The minimum inhibitory concentration (MIC) was determined for all the ligands and their complexes. The effect of ligand and complex structure on the antimicrobial activity was discussed.