Targeting the phospholipid repair system of Escherichia coli: New mechanistic insights into the antibacterial activity of sanggenon D from mulberry

Escherichia coli possesses a phospholipid repair system that serves as a bacterial resistance mechanism, complicating efforts to prevent and control infections. Sanggenon D, derived from mulberry, exhibits broad-spectrum antibacterial properties against various foodborne pathogens including E. coli. In this study, following treatment with sanggenon D (1.0 × MIC was 705.5 μmol/L), the number of E. coli colonies initially increased and then decreased significantly, which is markedly different from Staphylococcus aureus. These results suggest that sanggenon D may inhibit the phospholipid repair system in E. coli. Consequently, we further analyzed the regulation of protein expression levels involved in the phospholipid repair system and the glycerophospholipid profile after treatment with sanggenon D. The expression of proteins associated with maintaining membrane integrity, phospholipid recycling, and de novo phospholipid synthesis in E. coli was downregulated following treatment with sanggenon D, leading to a decrease in the glycerophospholipid profile. Our findings indicate that sanggenon D, derived from mulberry, may specifically target the phospholipid repair system in E. coli. These results could provide a theoretical basis for the further development of novel preservatives utilizing sanggenon D.