Carvacrol exhibits rapid bactericidal activity against Streptococcus pyogenes through cell membrane damage

Abstract

Streptococcus pyogenes is an important human pathogen worldwide. The identification of natural antibacterial phytochemicals has renewed interest due to the current scarcity of antibiotic development. Carvacrol is a monoterpenoid found in herbs. We evaluated carvacrol alone and combined with selected antibiotics against four strains of S. pyogenes in vitro. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of carvacrol against S. pyogenes were 125 µg/mL (0.53 mM) and 250 µg/mL (1.05 mM), respectively. Kill curve results showed that carvacrol exhibits instantaneous bactericidal activity against S. pyogenes. We also demonstrated the potential mechanism of action of carvacrol through compromising the cell membrane integrity. Carvacrol induced membrane integrity changes leading to leakage of cytoplasmic content such as lactate dehydrogenase enzymes and nucleic acids. We further confirmed dose-dependent rupturing of cells and cell deaths using transmission electron microscopy. The chequerboard assay results showed that carvacrol possesses an additive-synergistic effect with clindamycin or penicillin. Carvacrol alone, combined with clindamycin or penicillin, can be used as a safe and efficacious natural health product for managing streptococcal pharyngitis.

Carvacrol Suppresses Inflammatory Biomarkers Production by Lipoteichoic Acid- and Peptidoglycan-Stimulated Human Tonsil Epithelial Cells

“…Our findings indicate that carvacrol-containing lozenges or throat sprays for pharyngitis patients can be developed. Previously, we have found that carvacrol has rapid anti-streptococcal activity [ 17 ], and here, we provide evidence that carvacrol also possesses anti-inflammatory properties. More importantly, carvacrol is not cytotoxic to human epithelial cells and has been approved by the Food and Drug Administration (FDA) for use in foods (Code for Federal Regulation: 21CFR172.515).…”

“…We have recently demonstrated that carvacrol is not cytotoxic (3.9–250 µg/mL) to HTonEpiCs using the MTS assay [ 17 ]. To further assess whether carvacrol has a harmful effect on HTonEpiCs, the cells were incubated with carvacrol (8–250 µg/mL) or controls (DMSO as vehicle control, nimesulide as positive control) and the cell viability was analyzed by flow cytometry.…”

Synergistic antibacterial effects of carvacrol and ε-polylysine

“…However, the application of Car is limited due to the adverse sensory reaction caused by the amount of Car. The combination of Car with other antibacterial ingredients not only reduces the dosage and cost of Car but also widens its antibacterial spectrum and improves its application efficiency (Sharma et al, 2020;Wijesundara et al, 2021). This study verified the antibacterial effects of carvacrol and ε-PL alone, and in combination with E. coli and S. aureus.…”

Carvacrol Essential Oil: A Natural Antibiotic against Zoonotic Multidrug-Resistant Staphylococcus Species Isolated from Diseased Livestock and Humans

“…Carvacrol is a significant component of essential oils and has recently attracted much attention as a result of its biological properties including a wide spectrum of antimicrobial activity [50]. The MIC of carvacrol oil for the tested Staphylococcus isolates was 0.04%, as observed for a variety of microorganisms [50][51][52][53][54]. In addition, carvacrol was suggested as the bioactive compounds against S. aureus and other Gram-positive and Gram-negative bacteria [51].…”

“…It also possesses antifungal and antibiofilm properties, thus it can be used as an antimicrobial alternative against MDR pathogenic bacteria [ 50 ]. The MIC of carvacrol against different bacteria was detected as 400µg/mL [ 49 ] while it was 125µg/mL against S. pyogenes [ 54 ].…”