Synthesis, microbiological evaluation and mt-qsar of 3, 4-dimethoxy benzoic acid derivatives

In the present work, novel derivatives of veratric acid (V1- V34) were synthesized and tested in vitro for their antibacterial activity against Gram-positive bacteria Staphylococcus aureus, Bacillus subtilis and Gram negative bacteria Escherichia coli as well as antifungal activity against fungal strains Candida albicans and Aspergillus niger by standard serial dilution method using ciprofloxacin and fluconazole as reference compounds in case of antibacterial and antifungal activity respectively. The IR, 1H NMR and 13C NMR spectral data of the synthesized compounds were found in agreement with the assigned molecular structures. The investigation of antimicrobial screening data revealed that most of the synthesized compounds demonstrated good antimicrobial activity against all bacteria and fungi used in the study. Compounds (V2, V21, V25, V28) demonstrated most significant activity against C. albicans (MIC=6.25 µg/ml). The outcome of the study suggested that the test compound V28 may be utilized as potential antimicrobial agent against S. aureus, B. subtilis, E. coli, C. albicans and A. niger. mt-QSAR investigation with linear regression analysis was applied to find the relationship between chemical structures and biological activities of a series of analogs quantitatively. mt-QSAR studies revealed that antimicrobial activity of these synthesized derivatives against microorganisms under test mainly governed by topological parameters [valence zero order molecular connectivity index Vkier’s alpha second order shape index (2)] and electronic parameter [total energy (Te)].