Evaluation of the Antibacterial Activity and Efflux Pump Reversal of Thymol and Carvacrol against Staphylococcus aureus and Their Toxicity in Drosophila melanogaster

Abstract

The antibacterial activity and efflux pump reversal of thymol and carvacrol were investigated against the Staphylococcus aureus IS-58 strain in this study, as well as their toxicity against Drosophila melanogaster. The minimum inhibitory concentration (MIC) was determined using the broth microdilution method, while efflux pump inhibition was assessed by reduction of the antibiotic and ethidium bromide (EtBr) MICs. D. melanogaster toxicity was tested using the fumigation method. Both thymol and carvacrol presented antibacterial activities with MICs of 72 and 256 µg/mL, respectively. The association between thymol and tetracycline demonstrated synergism, while the association between carvacrol and tetracycline presented antagonism. The compound and EtBr combinations did not differ from controls. Thymol and carvacrol toxicity against D. melanogaster were evidenced with EC50 values of 17.96 and 16.97 µg/mL, respectively, with 48 h of exposure. In conclusion, the compounds presented promising antibacterial activity against the tested strain, although no efficacy was observed in terms of efflux pump inhibition.

Tannic Acid-Stabilized Silver Nanoparticles Used in Biomedical Application as an Effective Antimelioidosis and Prolonged Efflux Pump Inhibitor against Melioidosis Causative Pathogen

“…Ceftazidime antibiotic was used as a positive control. The plate was then incubated in an incubator at 37 °C for 18–24 h. MIC and MBC determination in different strains of B. pseudomallei (1026b, H777 and 316c) with broth microdilution and resazurin colorimetric assay were proposed by Silveira, et al and Teh, et al [ 65 , 66 ]. Broth microdilution was carried out with the same procedure as above.…”

“…For quantitative evaluation of efflux pump inhibition of AgNPs, microdilution assay was assessed with the slight modification previously described by Behdad, et al and Silverira, et al [ 28 , 65 ]. AgNPs, CAZ and EtBr were prepared in the concentration range of 0.125 to 512 µg/mL.…”

Thymol nanoemulsion promoted broiler chicken’s growth, gastrointestinal barrier and bacterial community and conferred protection against Salmonella Typhimurium

“…Recently, thymol was shown to play an important role in enhancing the intestinal barrier function and reducing the cytokine genes expression during inflammation 8 . Moreover, it possesses a strong antimicrobial efficacy against various pathogenic bacteria 9 .…”

Antibacterial Hybrid Hydrogels

“…studied the antibacterial activity of thymol against S. aureus and found that it had antibacterial activity against S. aureus , and its minimum inhibitory concentration (MIC) was 72 µg mL −1 . [ 61 ] Zhang et al. in situ polymerized antifouling polysulfide (PSf)/polyethersulfone (PES) and N‐ (5‐methacrylamide‐2,3,4‐hydroxy benzyl) acrylamide (AMTHBA) composite membrane (PSf/PES‐AMTHBA membrane) by microwave technique, in which the AMTHBA as a new capsaicin derivative could realize self‐polymerization due to the CC bond and endow the PSf/PES‐AMTHBA membrane with highly effective antibacterial activity against E. coli (>85%).…”