Effect of 1‐Hexyl‐3Methylimidazolium Bromide on the Antioxidant Property of Polyphenols: An Ecofriendly Alternative

ABSTRACT Polyphenols are naturally high‐valued secondary plant metabolites that demonstrate strong antimicrobial potential besides their well‐established health‐promoting benefits. The conventional polyphenolic extraction process mostly includes organic solvents, which cause environmental harm. In this context, ionic liquids (ILs) have emerged as an environmentally friendly substitute for traditional solvents to extract various active substances from plants such as coumarins, terpenoids, phenylpropanoids, and flavonoids. This study investigates the synthesis of 1‐hexyl‐3‐methylimidazolium bromide [HMIm][Br], an IL, and studies its impact on the antioxidant and antimicrobial properties of two polyphenolic compounds, gallic acid (GA) and tannic acid (TA), so that it can be effectively used in the extraction process. [HMIm][Br] was synthesized via alkylation and characterized through UV‐Vis, FTIR, and NMR techniques. The mixture of [HMIm][Br] with GA and TA demonstrated enhanced antioxidant activity in DPPH assays; 77% and 82%, respectively, in comparison to pure GA (64%) and TA (73%), suggesting improved free radical scavenging due to synergistic effects. Antibacterial and antibiofilm assays against Escherichia coli and Staphylococcus aureus revealed that when [HMIm][Br] was combined with GA or TA, antimicrobial efficacy was enhanced specifically for S. aureus when compared to the individual components. The zone of inhibition reported in case of S. aureus (GA: 9 mm; [HMIm][Br] + GA: 18 mm; TA: 9 mm; [HMIm][Br] + TA: 14 mm) and E. coli (GA: 8 mm; [HMIm][Br] + GA: 15 mm; TA: 10 mm; [HMIm][Br] + GA: 10 mm). Molecular docking studies supported these findings, indicating binding affinity of ([HMIm][Br]) to bacterial proteins, S. aureus (−5.0 kcal/mol) and E. coli (−4.0 kcal/mol). These results highlight the potential of [HMIm][Br] in improving the solubility, stability, and bioactivity of polyphenols, making the combination a promising candidate for applications in pharmaceuticals, food preservation, and cosmetics. The study contributes to the development of sustainable and effective polyphenol‐based formulations.