Complexation of trichlorosalicylic acid with alkaline and first row transition metals as a switch for their antibacterial activity

by Vijay Kumar, Mohit Chawla, Luigi Cavallo, Abdul Basit Wani, Anu Manhas, Sukhmanpreet Kaur, et.al.
Year: 2018 DOI: https://doi.org/10.1016/j.ica.2017.08.064

Extra Information

Inorganica Chimica Acta

Abstract

Although, 3,5,6-Trichlorosalicylic acid (TCSA) does not show good antibacterial activity, but its metal complexes have shown better activity for the selected bacterial strains with good degree of selectivity. Amongst the eight synthesized essential metal complexes of TCSA, Mn(II)-TCSA and Ni(II)-TCSA have been found to be more effective with MIC range of 20–50 µg/L as compared to control (chloramphenicol). The activity of an individual complex against different microbes was not identical, indicating the usage of an individual metal chelate against a targeted bacterial strain. Besides, the protein (BSA) binding constant of TCSA and its metal complexes were determined and ordered as Ca(II)-TCSA > Cu(II)-TCSA > Mg(II)-TCSA ≫ Mn(II)-TCSA ≫ Zn(II)-TCSA >>> Ni(II)-TCSA >>> Co(II)-TCSA > Fe(II)-TCSA > TCSA. The present study has confirmed enhanced antibacterial activity and binding constants for the metal chelates of TCSA in comparison to free TCSA, which seems directly related with the antioxidant activity of these complexes. Further, bearing the ambiguity related to the structural characterization of the metal complexed with TCSA ligand, DFT calculations have been employed as the tool to unravel the right environment around the metals, studying basically the relative stability of square planar and octahedral metal complexes of TCSA.


 

Keywords

Trichlorosalicylic acid Divalent essential metal complexes Antibacterial activity DFT calculation BSA protein binding