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

• Published in: Molecules (Basel, Switzerland) Switzerland), 2020-04, Vol.25 (9), p.2103
• Main Authors: Sousa Silveira, Zildene de, Macêdo, Nair Silva, Sampaio Dos Santos, Joycy Francely, Sampaio de Freitas, Thiago, Rodrigues Dos Santos Barbosa, Cristina, Júnior, Dárcio Luiz de Sousa, Muniz, Débora Feitosa, Castro de Oliveira, Lígia Claudia, Júnior, José Pinto Siqueira, Cunha, Francisco Assis Bezerra da, Melo Coutinho, Henrique Douglas, Balbino, Valdir Queiroz, Martins, Natália
• Format: Article
• Language: English
• Subjects: Animals; Antagonism; Anti-Bacterial Agents - pharmacology; Antibacterial activity; Antibacterial materials; Antibiotics; bacterial resistance; Carvacrol; Cymenes - chemistry; Cymenes - pharmacology; Dose-Response Relationship, Drug; Drosophila melanogaster; Drosophila melanogaster - drug effects; Drug resistance; Efflux; efflux pumps; Ethidium bromide; Fumigation; Hazardous materials; Insecticides - pharmacology; Insects; Microbial Sensitivity Tests; Minimum inhibitory concentration; Molecular Structure; Mortality; Staphylococcus aureus; Staphylococcus aureus - drug effects; Synergism; terpenoids; Thymol; Thymol - chemistry; Thymol - pharmacology; Toxicity; Toxicity testing
• ISSN: 1420-3049; 1420-3049
• DOI: 10.3390/molecules25092103

The antibacterial activity and efflux pump reversal of thymol and carvacrol were investigated against the IS-58 strain in this study, as well as their toxicity against . 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. 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 were evidenced with EC 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.