In vitro antifungal activity, cytotoxicity and binding analysis of imidazolium based ionic liquids with fluconazole: DFT and spectroscopic study

Fungal infections represent a significant challenge in various living organisms, including humans, animals, and plants. Fungi are versatile organisms capable of thriving in diverse environments, which contributes to their widespread presence and potential to cause infections. Recently, imidazolium-based ionic liquids emerged as good antimicrobial agent in either monomeric or polymeric form. Therefore, herein, we have reporting the in-vitro antifungal activity, cytotoxicity, and binding analysis of 1-decyl-3-methylimidazolium chloride, [C₁₀Mim][Cl] and 1-hexyl-3-methylimidazolium chloride, [C₆Mim][Cl] ionic liquids with fluconazole (Flz). The antifungal activity of ILs and ILs with Flz against candidiasis species (C. albicans) in terms of minimum inhibitory concentration (MIC) was assessed. The antifungal activity results showed that [C₁₀Mim][Cl]-Flz exhibit good antifungal activity then [C₁₀Mim][Cl] and Flz alone. The cytotoxicity of ILs with Flz was checked against human embryonic kidney (HEK293) cell line regarding cell viability and result showed minute cytotoxicity of the combinations at higher concentrations. Further, the binding of ILs with Flz was also studied using various techniques such as UV–visible, fluorescence, Fourier-transform infrared (FTIR) spectroscopy, isothermal titration calorimetry (ITC), and conductivity method. It was found that [C₁₀Mim][Cl] shows more binding affinity then [C₆Mim][Cl] with Flz. In-silico molecular docking analysis of Flz-[C₁₀Mim][Cl] complex show a higher binding affinity with CYP51 which in turn enhanced its ability to inhibit the ergosterol biosynthesis as compared to alone [C₁₀Mim][Cl] and Flz. The classical density functional theory (DFT) model was also utilized which further supports the spectroscopic results.