Jessyca Nayara Mascarenhas Lima , Cristina Rodrigues dos Santos Barbosa , Joycy Francely Sampaio dos Santos , Jackelyne Roberta Scherf , Thiago Sampaio de Freitas , Larissa da Silva , Nair Silva Macêdo , Catarina Martins Tahim , Elaine Cristina Pereira Lucetti , Emmanuel Silva Marinho , Hélcio Silva dos Santos , Micheline Azevedo Lima , Henrique Douglas Melo Coutinho , Francisco Assis Bezerra da Cunha
{"title":"ADMET analysis and evaluation of the effect of ortho-eugenol on the QacA/B efflux pump of Staphylococcus aureus","authors":"Jessyca Nayara Mascarenhas Lima , Cristina Rodrigues dos Santos Barbosa , Joycy Francely Sampaio dos Santos , Jackelyne Roberta Scherf , Thiago Sampaio de Freitas , Larissa da Silva , Nair Silva Macêdo , Catarina Martins Tahim , Elaine Cristina Pereira Lucetti , Emmanuel Silva Marinho , Hélcio Silva dos Santos , Micheline Azevedo Lima , Henrique Douglas Melo Coutinho , Francisco Assis Bezerra da Cunha","doi":"10.1016/j.prenap.2025.100194","DOIUrl":null,"url":null,"abstract":"<div><div>Antimicrobial resistance (AMR) is a significant global problem, with <em>Staphylococcus aureus</em> being a prominent multidrug-resistant bacterium, mainly due to mechanisms such as β-lactamase production and the QacA/B efflux pump system. These mechanisms impede effective treatment of the infection, necessitating the development of innovative therapeutic strategies. In this context, natural products such as ortho-eugenol, a synthetic isomer of eugenol, have attracted attention for their potential to modulate bacterial resistance. This study evaluated the antimicrobial activity of ortho-eugenol against <em>S. aureus</em> K4414, a strain harboring the QacA/B efflux pump. Despite having a minimum inhibitory concentration (MIC) of ≥ 1024 μg/mL, indicating weak antibacterial activity, its combination with penicillin resulted in a fivefold reduction in the MIC of the antibiotic (from 512 μg/mL to 101.6 μg/mL). This potentiating effect was not observed with the standard efflux pump inhibitor chlorpromazine, suggesting that the mechanism is not related to QacA/B inhibition but likely involves β-lactamase inhibition, as confirmed by the combination of ampicillin with sulbactam. In addition, ortho-eugenol in combination with ethidium bromide (EtBr) increased the MIC of EtBr, suggesting an antagonistic interaction. In contrast, chlorpromazine with EtBr decreased its MIC, confirming the functionality of the QacA/B efflux pump. Biophysical and predictive analyses revealed that ortho-eugenol has lipophilic properties and moderate metabolic stability, making it suitable for oral bioavailability with low central nervous system toxicity. However, a structural vulnerability related to the isolated alkene group was identified, indicating potential epoxidation during phase I metabolism, warranting controlled dosing. These findings highlight the potential of ortho-eugenol as a β-lactamase inhibitor.</div></div>","PeriodicalId":101014,"journal":{"name":"Pharmacological Research - Natural Products","volume":"6 ","pages":"Article 100194"},"PeriodicalIF":0.0000,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Pharmacological Research - Natural Products","FirstCategoryId":"1085","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S2950199725000540","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 0
Abstract
Antimicrobial resistance (AMR) is a significant global problem, with Staphylococcus aureus being a prominent multidrug-resistant bacterium, mainly due to mechanisms such as β-lactamase production and the QacA/B efflux pump system. These mechanisms impede effective treatment of the infection, necessitating the development of innovative therapeutic strategies. In this context, natural products such as ortho-eugenol, a synthetic isomer of eugenol, have attracted attention for their potential to modulate bacterial resistance. This study evaluated the antimicrobial activity of ortho-eugenol against S. aureus K4414, a strain harboring the QacA/B efflux pump. Despite having a minimum inhibitory concentration (MIC) of ≥ 1024 μg/mL, indicating weak antibacterial activity, its combination with penicillin resulted in a fivefold reduction in the MIC of the antibiotic (from 512 μg/mL to 101.6 μg/mL). This potentiating effect was not observed with the standard efflux pump inhibitor chlorpromazine, suggesting that the mechanism is not related to QacA/B inhibition but likely involves β-lactamase inhibition, as confirmed by the combination of ampicillin with sulbactam. In addition, ortho-eugenol in combination with ethidium bromide (EtBr) increased the MIC of EtBr, suggesting an antagonistic interaction. In contrast, chlorpromazine with EtBr decreased its MIC, confirming the functionality of the QacA/B efflux pump. Biophysical and predictive analyses revealed that ortho-eugenol has lipophilic properties and moderate metabolic stability, making it suitable for oral bioavailability with low central nervous system toxicity. However, a structural vulnerability related to the isolated alkene group was identified, indicating potential epoxidation during phase I metabolism, warranting controlled dosing. These findings highlight the potential of ortho-eugenol as a β-lactamase inhibitor.