American Journal of Applied Chemistry 2013; 1(4): 59-66 Published online November 10, 2013 (http://www.sciencepublishinggroup.com/j/ajac) doi: 10.11648/j.ajac.20130104.13 Synthesis, Characterization and in vitro Antimicrobial studies of Schiff-bases derived from Acetyl acetone and Amino acids and their Oxovanadium(IV) complexes Misbah ur Rehman 1 , Muhammad Imran 2, * , Muhammad Arif 2 1 Institute of Chemical Science, Gomal University, D.I. Khan, KPK, Pakistan 2 Institute of Chemical Science, Bahauddin Zakariya University, Multan, Pakistan Email address: imran345@hotmail.com (M. Imran) To cite this article: Misbah ur Rehman, Muhammad Imran, Muhammad Arif. Synthesis, Characterization and in Vitro Antimicrobial Studies of Schiff-Bases Derived from Acetylacetone and Amino Acids and their Oxovanadium(IV) Complexes. American Journal of Applied Chemistry. Vol. 1, No. 4, 2013, pp. 59-66. doi: 10.11648/j.ajac.20130104.13 Abstract: A series of novel amino acid derived Schiff-bases and their Oxovanadium(IV) complexes were synthesized and well characterized by elemental analyses, spectral studies, conductivity and magnetic measurements. Physical and analytical data suggest that the Schiff bases act as tridentate ligands towards metal ion via azomethine-N, deprotonated-O of carboxylic group and enolic-O group of acetylacetone. All the complexes have lower molar conductance values, indicating their non-electrolytic nature. The synthesized ligands, along with their metal complexes were screened for their in-vitro antibacterial activity against two Gram-negative (Escherichia coli, Salmonella typhi) and two Gram-positive (Bacillus subtilis, Staphylococcus aureus) bacterial strains and for in vitro antifungal activity against Trichophyton longifusus, Candida albicans, Aspergillus flavus, and Candida glaberata species. The results of these studies revealed that all the compounds and their metal complexes showed significant antibacterial and antifungal potency. Brine shrimp bioassay was also carried out for in vitro cytotoxic properties against Artemia salina. Keywords: Schiff-bases, Amino Acid, Antibacterial, Antifungal, Cytotoxicity 1. Introduction Schiff base are an important class of ligands in coordination chemistry due to not only their useful physical and chemical properties and large number of reactions they undergo but also have very wide use in industry and due to their interesting pharmacological as well as physiological activities.[1,2] They are also important intermediate in the enzymatic reactions involving interaction of an enzyme with an amino or a carbonyl group of the substrate.[3] It is possible to introduce different substituents into the existing skeleton of the molecule, hence enabling the designing of compounds with the suitable structural, electronic and biological properties.[4] In recent years, Schiff base complexes of amino acid have received considerable attention because of their physiological and pharmacological activities.[5,6] In metal coordination chemistry Schiff bases continue to occupy an important position as ligand ions due to the incorporation of transition metals into Schiff bases. This results in an increase in biological activity of the ligand and decrease in the cytotoxic effects of both the metal ion and ligand on the host.[7] Metal ions play a catalytic role in reactions of Schiff bases. The development in the field of bioinorganic chemistry has increased the interest in Schiff base complexes, since it has been recognized that many of these complexes may serve as models for biologically important species. It have also been reported that metal complexes of amino acid Schiff bases possess anti-carcinogenic activities.[8] The coordination behavior of schiff bases with Vanadium is of great interest because of the presence of Vanadium in biological systems as trace element. The geometry of vanadyl complexes is highly dependent on the chelating properties of ligands.[9,10] It have been observed that schiff bases form stable complexes with oxovanadium(IV) salts with five or six coordinated state of V(IV).[11] A square pyramidal or distorted trigonal bipyramidal geometry is reported for five coordinated complexes[12] while distorted octahedral structure is observed for the six coordinated ones.[13] In past few years attentions have been focused on the synthesis of low