Synthesis, Characterization and Bacterial Growth Inhibitory Properties of Schiff-Base Ligands Derived from Amino Acids

Abstract

Schiff-base ligands and their metal complexes are attracting a lot of research in bioinorganic and medicinal chemistry owing to their improved activity in biological systems. Six schiff-base ligands derived from amino acids; N- Salicylidene Alanine, N-Salicylidene Serine, N-Benzalidene Histidine, N-Balzalidene Leucine, N-4-(dimethylamino) benzalidene Phenylalanine, and N-4-(dimethylamino)benzalidene Valine have been synthesized, characterized and their bacterial growth inhibitory properties determined against Staphylococcus aureus and Escherichia coli. These schiff-bases are synthesized by the condensation reaction between carbonyl compounds (aldehydes and ketones) and amines (amino acids). Characterization of the schiff-base ligands is done using melting/decomposition temperatures, FTIR spectroscopy, US-visible spectroscopy, and solubility. It is observed that, all the schiff-base ligands contain the imine or azomethine (C=N) group with a stretching frequency ranging from 2200 - 2400 cm-1. In addition, all the schiff-base ligands are seen to be soluble in water, which is paramount in their application in biological systems. The structures of the schiff-base ligands were deduced based on the characterization techniques. Furthermore, the bacterial growth inhibitory properties of the schiff-base ligands were done using the Agar Well Diffusion method. The results reveal that, all the schiff-base ligands show no toxicity effect or negative bacterial growth properties against gram positive (Staphylococcus aureus) and gram negative (Escherichia coli) bacteria.