The influence of dihydroquercetin on the cell membrane model of Clavibacter michiganensis subsp. sepedonicus.

Dihydroquercetin (DHQ) exhibited antimicrobial activity associated with its interaction with bacterial cell membranes. However, molecular-level mechanism has not been revealed. Therefore, this study investigated the potential interactions between DHQ and model membrane by constructing a Clavibacter michiganensis subsp. sepedonicus (Cms) membrane model. The optimization of preparation condition was sonicated 45 °C for 20 min determined by dynamic light scattering (DLS). The average particle size of the liposomes showed an average particle size of 162.43 ± 2.41 nm, with zeta potential of -26.77 ± 0.64 mV and PDI of 0.26 ± 0.01. Atomic force microscopy (AFM) showed that liposomes were uniformly spherical. Subsequently, further analysis was conducted on the effect of DHQ on the membrane. Through AFM observation, it was found that the morphology of liposomes was irregular, with significantly increased membrane adhesion, height and roughness, while the Young's modulus decreased. The absolute value of Zeta potential significantly decreased (P < 0.05), indicating that the membrane was more prone to aggregation. Phosphorus-31 nuclear magnetic resonance (31P NMR) showed that DHQ changed the microenvironment of the P atom in the phospholipid head. Molecular dynamics (MD) simulations indicated that DHQ was more likely to act on the hydrophilic region of the 1,2-dipalmitoyl-sn-glycero-3-phospho-(1'-rac-glycerol) (DPPG) membrane to form hydrogen bonds, and had a tendency to penetrate into the hydrophobic region of the membrane. These findings provided important molecular-level evidence for a deeper understanding of antibacterial effects of DHQ.