In-vitro antifungal study of Cu (II) complexes with a heterocyclic N donor ligand

Biguanide, C2H7N5 is a nitrogen donor bidentate ligand and its derivative, piperazinedibiguanide C8H18N10 is a nitrogen donor tetradentate ligand. The tetradentate ligand, piperazinedibiguanide was prepared and complexed with Cu (II) by reaction of the ligand with Cu (II) salts. The characterization of the complexes – elemental analysis and magnetic property was reported in laboratory along with spectral characteristics. All prepared Cu (II) complexes were paramagnetic which confirm its square planar structure. Further their antifungal activity against two common ascomycetes was studied by using disc dilution test method in Potato Dextrose Agar and Sabourand Dextrose Agar media. During the tests, the concentration of the complexes of copper with piperazinedibiguanide ligand were 400µg/ml, 200µg/ml and 100µg/ml. The tests reported a positive response againstthe growth of Aspergillus niger and Aspergillus vesicolor in both the media. All complexes have shown more than 80% inhibition in fungal growth at concentration 400 µg/ ml. One of the complexes, Copper piparazinedibiguanide hydroxide reported reduction in the fungal growth of Aspergillus versucolorby 100% and 99.10% in Potato Dextrose Agar and Sabourand Dextrose Agar media respectively. Thus, in vitro Minimum Inhibitory Concentration results during the study suggest further study of antifungal activity of transition metal complexes of said ligand with other microbes as well.