Inhibition of (p)ppGpp Synthesis and Membrane Fluidity Modulation by Diosgenin: A Strategy to Suppress Staphylococcus aureus Persister Cells.

Persister cells are a subset of bacterial cells that exhibit transient antibiotic tolerance without genetic resistance, contributing to the persistence of chronic infections. This study investigates the ability of diosgenin, a naturally occurring steroidal saponin, to inhibit persister cell formation in Staphylococcus aureus through metabolic suppression and membrane modulation. Diosgenin treatments at 80 µM and 160 µM significantly reduced persister cell survival under oxacillin, ciprofloxacin, and gentamicin stress, with reductions ranging from 82% to 94% after 3 h diosgenin pre-exposure. Gene expression analysis revealed that diosgenin downregulated relP and relQ, key genes involved in (p)ppGpp synthesis, by up to 60%, accompanied by 36-38% decreases in intracellular ATP levels. Diosgenin did not significantly alter membrane permeability or membrane potential but reduced membrane fluidity by 35% and 41% at 80 µM and 160 µM, respectively. Taken together, our findings suggest that diosgenin exerts a dual-action regulatory effect on persister cell formation by disrupting metabolic pathways essential for dormancy and altering membrane dynamics, potentially affecting membrane-associated signaling. This study provides a framework for the further exploration of diosgenin as a potential anti-persister agent with particular promise for use in combination with conventional antibiotics to enhance therapeutic efficacy against chronic bacterial infections.