Synthesis and study of anti-bacterial activity of complexes of diallyldisulphide from garlic

Background: The development of bacterial resistance to available antibiotics and increasing incidence of multiresistant bacterial infections in hospitals and in the community has necessitated the search for new antibacterial agents to treat the bacterial infection. It has long been known that metal ions are involved in biological processes of life through bonding to the heteroatoms of the heterocyclic residues of biological molecules i.e., proteins, enzymes and nucleic acids etc. The behavior of the disulfide group as a donor in transition metal complexes has not been subjected to such detailed study as a number of other donor groups. Aim: The Diallyldisulphide is one of the main constituents of Allium sativum (Garlic). The antibacterial and antifungal activity of the Garlic is due to the presence of sulphur containing compounds. The aim of the present work was to synthesize metal complexes with Diallyldisulphide. Materials and Methods: Complexation reactions between the Diallyldisulphide and the metal ions were carried out at three different pH i.e. acidic (pH 3), neutral (pH 7) and alkaline (pH 10) using three different ratios of metal ligand namely 1:1, 1:2, 1:3, respectively. Complex formation with the ligand and all the metals took place at pH 10, indicating that complexes were stable at this pH. Studies with different metal: ligand ratio showed that in case of silver the complexation took place at 1:1 ratio. In case of divalent metals, the appropriate ratio of metal: ligand was 1:2. The structures of the new complexes obtained were determined by spectroscopic methods. Results and Discussion: Synthesized complexes were investigated for antimicrobial activity against Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumoniae and E.coli. Diallyldisulphide-silver complex exhibited significant antibacterial activity (MIC 100 μg/ mL), and was found to be effective against selected organisms. The results concluded that the metal complexes are better antibacterial agents as compared to the silversulphadiazine.