Synthesis, structure, biological/chemosensor evaluation and molecular docking studies of aminobenzothiazole Schiff bases

Abstract

Two Schiff bases derived from aminobenzothiazole derivatives with Salicylaldehyde/Bromosalicylaldehyde namely 2-[6-Methylbenzothiazol-2-ylimino) methyl phenol (1) and 3-Bromo-2-[6-methylbenzothiazol-2-ylimino) methyl phenol (2) were synthesized using simple condensation method and characterized using various spectral techniques like FT-IR, NMR, analytical data and single crystal XRD. Schiff base 1 crystallized in monoclinic crystal system with the space group P121/n1. Schiff base 2, the structure was optimized using Gaussian 09 program (UB3LYP methods, [6–31G (d, p)] basis sets). The antimicrobial activity of the Schiff bases was screened for various test organisms like Pseudomonas aeruginosa (P. aeroginosa) (ATCC: 15442), Escherichia coli (E. coli) (ATCC: 5922), Serratia marcescens (S. marcescens) (ATCC: 14756), Acinetobacter baumannii (A. baumauii) (ATCC: 43498), Aspergillus niger (A. niger) (ATCC: 6275) and Candida albicans (C. albicans (ATCC: 10231) and found to be good. The cytotoxic potential of Schiff bases was evaluated against MCF-7 cells in terms of IC50 values [80.19 μM (1) and 44.12 μM (2)] and the results show moderate activity. The anti-tuberculosis activity was the minimum inhibitory concentration (MIC) while screening the anti-tuberculosis activity of 2 was found to be 1.6 μg/mL which is lower than that of the standard drug Pyrazinamide, Streptomycin and Ciprofloxacin. Molecular docking studies were done using molecular operating environment (MOE) program on the 3D structure of the enzymes namely, human thymidylate synthase complexed with DUMP and Raltitrex, Candida albicans N-myristoyltransferasepeptidic inhibitor, protein kinase pKnb in complex with Mitoxantrone, Pare, Topoisomerase atpase inhibitor, E. coli and Lactobacillus casdihydrofolatereductase and the interactions with the active site is reported. The chemosensor application of the schiff bases were studied using absorption and emission spectral measurements.