Virtual screening unearths baicalin as a promising inhibitor of Pseudomonas fluorescens cold defense mechanism

The psychrotrophic spoilage bacterium Pseudomonas fluorescens poses a challenge to seafood preservation through the action of functional cold-defense proteins. This study aimed to identify natural inhibitors targeting this mechanism in P. fluorescens PF08. Through virtual screening, potential inhibitory compounds were identified, with baicalin being further evaluated. The effects of baicalin were validated using bacterial growth assays conducted at 4°C and room temperature, biofilm quantification, and the analysis of key protein expression, including RpoS, AlgK, and RelA. Baicalin selectively inhibited the growth and biofilm formation of P. fluorescens PF08 at 4°C, while exhibiting minimal activity at room temperature. It significantly downregulated the expression of cold-defense proteins RpoS, AlgK, and RelA, thereby disrupting their function. These findings suggest that baicalin specifically interferes with the cold-adaptation mechanism of P. fluorescens at refrigeration temperatures, presenting a novel approach for mitigating seafood spoilage. • An inhibitor, baicalin, was found to synergize with cold to inhibit bacteria. • Following treatment with baicalin, Pseudomonas exhibited impaired growth at 4°C. • Metabolomic analysis revealed that baicalin inhibits biofilm formation. • Molecular docking analysis indicated that baicalin interacts with three proteins. • None.