Synthesis, characterization and molecular docking study of novel bile acid curcumin conjugates as potent...

Two novel bile acid-curcumin conjugates were synthesized via esterification of curcumin with cholic acid and deoxycholic acid. FT-IR, ¹H &¹³C NMR and HPLC spectral data were employed to characterize the synthesized conjugates. Conjugate 3a exhibited significant antibacterial activity against Pseudomonas putida (ATCC 25922) with an IC₅₀ 4.48 ± 0.2 µg/mL. Conjugate 3b showed efficacy against Bacillus megaterium (QMB 1551) with an IC₅₀ of 7.02 ± 0.4 µg/mL. Both conjugates demonstrated higher antibacterial efficacy compared to curcumin, which had IC₅₀ values of 46.09 ± 2.6 and 76.02 ± 5.2 µg/mL, respectively. Conjugate 3a showed strong antibiofilm activity it reduced biofilm biomass of Bacillus megaterium (QMB1551) and Lactococcus lactis (NZ900) by nearly 90% at a concentration of 80 µg/mL. It also inhibited approximately 50% of biofilm formation in L. lactis and P. putida, with MIC₅₀ values of 24.8 ± 1.3 and 28.3 ± 0.4 µg/mL, respectively. In silico analysis showed Conjugate 3a exhibited a binding affinity of - 7.11 kcal/mol against bacterial outer membrane protein (PDB ID: 4RHB), compared to curcumin's - 2.99 kcal/mol. Moreover, the conjugate 3a exhibited a higher affinity - 8.12 kcal/mol than curcumin - 6.49 kcal/mol against the cell division protein (PDB ID: 6LL6). These results highlight the enhanced ability of conjugate 3a to interact with and inhibited essential bacterial targets, supporting its potential as a promising antibacterial agent.