As a result of the serious issues connected to the bacterial infections, there is an imperious need to improve strong and ecofriendly antimicrobial polymers to overcome the limitations of conventional antimicrobial agents. In this trend, poloxamines (Tetronics) which are X‐shaped poly(ethylene oxide)–poly(propylene oxide) diblocks linked to a focal ethylenediamine group; were successfully modified to produce Tetronic Schiff base for enhancing the biological activities of Tetronic 1107. Modification of tetronic 1107 (T1107) was proceeded throughout chloroacetylation of T1107 followed by amination using p‐phenylenediamine then the latter was treated with different aldehydes to yield Tetronic Schiff bases. Characterization of Tetronic Schiff bases was carried out by 1H‐NMR, Fourier‐transform infrared spectroscopy, X‐ray diffraction, elemental analysis and thermogravimetric analysis (TGA) analyses. The antimicrobial activities of four tested compounds coded (EK1, EK2, EK3, and EK4) were quantified using Microtiter‐assay methods. The obtained data revealed potential antimicrobial activities for tested compounds against all tested microbes with priority against Pseudomonas aeruginosa, Escherichia coli and Staphylococcus aureus. Sample coded EK4 exhibited the most effective treatment against P. aeruginosa, Candida albicans, S. aureus and E. Coli with minimal inhibitory concentration values of 6, 16, 12.5, and 1.5 μM, respectively. Furthermore, the safety results confirmed that EK4 and EK1 were the safest treatment with IC50 values of 76.01 and 62.67 μM, respectively. In addition, all tested compounds showed significant anticancer effects against MDA‐MB‐231cell line, while EK3 was effective treatment against A549 cell line with IC50 values of 39.63 μM. Meanwhile, both EK2 and EK4 showed the highest selectivity index (SI) values against MDA‐MB‐231 cell line with values 2.5 and 3.07, respectively. Interestingly, EK4 showed the maximum SI values on A549 and Hep‐G2 cell lines with values 1.62 and 1.52, respectively.
The hydroxyl end groups of Tetronic T1107 were modified with chloroacetyl chloride. The chloroacetylated Tetronic T1107 was then modified to introduce amino group in the side chain by reacting it with ethylenediamine. New Schiff bases were synthesized by the reaction of aminated Tetronic 1107 with different aromatic aldehydes such as p-hydroxybenzaldehyde, vanillin, pchlorobenzaldehyde, and p-dimethylamino benzaldehyde. The chemical structure of the obtained Schiff bases was confirmed by FT-IR and 1H-NMR spectroscopy. The antibacterial activity of Schiff base compounds was investigated by well diffusion method against gram-negative bacteria (Escherichia coli, Klebsiella pneumoniae, Proteus vulgaris) and grampositive bacteria (Staphylococcus aureus). The results showed that the polymeric Schiff base compounds have a significant inhibiting effect on all the tested microorganisms. It was also found that the antibacterial activity of the Schiff base was higher than that of unmodified tetronic 1107.
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