The Primary Mode of Action of Lippia graveolens Essential Oil on Salmonella enterica subsp. Enterica Serovar Typhimurium

• Published in: Microorganisms (Basel) Vol. 11; no. 12; p. 2943
• Main Authors: Rubio Ortega, Annie, Guinoiseau, Elodie, Poli, Jean-Pierre, Quilichini, Yann, de Rocca Serra, Dominique, del Carmen Travieso Novelles, Maria, Espinosa Castaño, Ivette, Pino Pérez, Oriela, Berti, Liliane, Lorenzi, Vannina
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 08.12.2023
• Subjects: absorption; Antibiotics; Antimicrobial agents; ATP; Bacteria; botanical product; carvacrol; cytoplasmic membrane; death; Depolarization; Essential oils; etiological agents; fluorescence; Food safety; foodborne bacteria; Foodborne diseases; Gram-negative bacteria; Gram-positive bacteria; Intracellular; Leakage; Lippia graveolens; Lysis; mechanism of action; Medical research; Membrane potential; Membranes; Mode of action; Natural resources; Oils & fats; Pathogens; protein content; Public health; R&D; Research & development; Salmonella; Salmonella enterica; shrinkage; thymol; Transmission electron microscopy; Ultrastructure; Zoonoses; Cuba; Palo Alto California; United Kingdom > UK; United States > US; thymol; carvacrol; foodborne bacteria; botanical product; cytoplasmic membrane
• ISSN: 2076-2607; 2076-2607
• DOI: 10.3390/microorganisms11122943

Essential oils are known to exhibit diverse antimicrobial properties, showing their value as a natural resource. Our work aimed to investigate the primary mode of action of Cuban Lippia graveolens (Kunth) essential oil (EO) against Salmonella enterica subsp. enterica serovar Typhimurium (S. enterica ser. Typhimurium). We assessed cell integrity through various assays, including time-kill bacteriolysis, loss of cell material with absorption at 260 and 280 nm, total protein leakage, and transmission electron microscopy (TEM). The impact of L. graveolens EO on membrane depolarization was monitored and levels of intracellular and extracellular ATP were measured by fluorescence intensity. The minimum inhibitory and bactericidal concentrations (MIC and MBC) of L. graveolens EO were 0.4 and 0.8 mg/mL, respectively. This EO exhibited notable bactericidal effects on treated cells within 15 min without lysis or leakage of cellular material. TEM showed distinct alterations in cellular ultrastructure, including membrane shrinkage and cytoplasmic content redistribution. We also observed disruption of the membrane potential along with reduced intracellular and extracellular ATP concentrations. These findings show that L. graveolens EO induces the death of S. enterica ser. Typhimurium, important information that can be used to combat this foodborne disease-causing agent.