The effect of alkyl chain and electronegative atoms in anion on biological activity of anilinium carboxylate bioactive ionic liquids and computational approaches by DFT functional and molecular docking

Heliyon. 2021 Jul 8;7(7):e07509. doi: 10.1016/j.heliyon.2021.e07509. eCollection 2021 Jul.

Abstract

The Brønsted acid-base neutralization was executed for synthesis of the anilinium carboxylate ionic liquids (ACILs), and obtained highly viscous liquids with yields about (90-94)%. These ILs were purified by distillation process and used vacuum oven, as well as characterized by FT-IR, UV spectroscopy and 1H-NMR. To evaluate the antimicrobial activity, the well diffusion method was used against eight human pathogenic bacteria, showing inhibition of zone at 13 mm-27 mm, and three fungi with result about 60%. Plus, the DFT functional from material studio 8.0 was used for evaluation of computational screening for estimating the chemical reactivity, HOMO, LUMO and HOMO-LUMO gap, recorded from -7.252 to -8.20 kcal/mol. The IL05 has showed about -6.5 kcal/mol docking score as standard inhibitor, as and higher than starting. Form AMDET properties, it has revealed that they have low toxicity, higher absorption through the biological system and non-carcinogenic. Finally, the electronegative groups, such as F, Cl and Br atoms in anion can show the higher antimicrobial activity and molecular docking score among all others while F atom containing IL05 shows the highest docking score and antimicrobial activity. However, it is concluded that rather than long large alkyl chain of anion, F atom (the highest electronegative atom) containing anion is better for biologically significance ILs.

Keywords: Antimicrobial activity; DFT; HOMO; Ionic liquids; LUMO and ADMET; Well-diffusion method.