Synthesis and in vitro anticancer, antibacterial, and antioxidant studies of unsymmetrical Schiff base derivatives of 4-[(1E)-N-(2-aminoethyl)ethanimidoyl] benzene-1,3-diol

Schiff bases such as 2-hydroxy-1-(4-hydroxyphenyl) ethanone (DHAP) and its derivatives have attracted attention because they are useful in design and development of novel organic compounds for potential pharmaceutical applications. In this work, a series of 4-[(1E)-N-(2-aminoethyl) ethanimidoyl] benzene-1,3-diol (4a-h) Schiff bases were synthesized by reaction of ethylenediamine, DHAP, and appropriate aldehyde moieties. The compositions of the prepared compounds were established using elemental analysis and Fourier-transform infrared (FTIR) and ultraviolet-visible (UV-Vis) spectroscopies. The compounds were screened against three Gram-positive and three Gram-negative bacteria, and the results compared with standard drugs ciprofloxacin and amoxicillin. Compounds 4g, 4h were found to have higher activity against Staphylococcus aureus with minimum inhibitory concentration (MIC) value of 2.5 mg/mL, while compounds 4f and 4h inhibited Escherichia coli with MIC values of 2.5 and 5 mg/mL, respectively. The IC50 values of compounds 4a-h for scavenging 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical ranged from 2.63 +/- 0.79 to 3.85 +/- 0.83 mu M with good correlation coefficient of R-2 = 0.957-0.994. In vitro anticancer screening of the compounds showed that compounds 4f, 4h, and parthenolide efficiently affected cell viability of cancer cell line MCF-7 with IC50 values of 4.10 +/- 1.32, 4.01 +/- 2.26, and 0.44 +/- 2.02 mu M, respectively.