Antibacterial activity of Shallots (Allium xwakegi Araki.) cultivars in Palu Valley against Salmonella Typhi ATCC 27870 through in vitro and in silico evaluation

Background and Objectives: Shallots, recognized for their minimal toxicity, cost-effectiveness, and widespread avail- ability, are increasingly considered a viable source of biological activity. This study evaluates the antibacterial efficacy of a specific shallot cultivar from Palu Valley, Indonesia, against Salmonella typhi, the pathogen responsible for typhoid fever. Materials and Methods: Utilizing thin-layer chromatography (TLC-bioautography) and gas chromatography-mass spec- troscopy (GC-MS), the study identifies active compounds in shallot ethanol extract and employs molecular docking to assess interactions between receptors and ligands. Results: Findings indicate significant antibacterial activity, with a notable inhibition zone diameter of 31.5 mm at spot Rf 0.28 in TLC bioautography and an optimum concentration of 2% yielding an average clear zone diameter of 28.27 mm in the agar diffusion test. GC-MS analysis reveals 41 compounds, predominantly dodecanoic acid and 1,2,3-propanetriyl ester. Ad- ditionally, molecular docking reveals the lowest binding affinity (-7.3 kcal/mol) for Ergost-8-En-3-Ol, 14-Methyl-, (3.Beta,5. Alpha.) against DNA gyrase. Conclusion: This study confirms Palu Valley shallot extract's potent antibacterial effect against Salmonella typhi, highlight- ing its therapeutic potential.