Synergistic and Antibiofilm Effects of the Essential Oil from Croton conduplicatus (Euphorbiaceae) against Methicillin-Resistant Staphylococcus aureus

Genil Dantas de Oliveira; Wilma Raianny Vieira da Rocha; José Filipe Bacalhau Rodrigues; Harley da Silva Alves

doi:10.3390/ph16010055

Synergistic and Antibiofilm Effects of the Essential Oil from Croton conduplicatus (Euphorbiaceae) against Methicillin-Resistant Staphylococcus aureus

Pharmaceuticals (Basel). 2022 Dec 30;16(1):55. doi: 10.3390/ph16010055.

Authors

Genil Dantas de Oliveira¹, Wilma Raianny Vieira da Rocha¹, José Filipe Bacalhau Rodrigues², Harley da Silva Alves¹

Affiliations

¹ Postgraduate Program in Pharmaceuticals Sciences, Department of Pharmacy, State University of Paraiba, Campina Grande 58429-500, Brazil.
² Postgraduate Program in Materials Science and Engineering, Department of Materials Engineering, Federal University of Campina Grande, Campina Grande 58429-900, Brazil.

Abstract

Bacterial resistance refers to the ability of bacteria to resist the action of some antibiotics due to the development of adaptation and resistance mechanisms. It is a serious public health problem, especially for diseases caused by opportunistic bacteria. In this context, the search for new drugs, used alone or in combination, appears as an alternative for the treatment of microbial infections, and natural products, such as essential oils, are important in this process due to their structural diversity, which increases the probability for antimicrobial action. The objective of this study was to extract and identify the chemical components of the essential oil from Croton conduplicatus (EOCC), to evaluate the antimicrobial activity, to investigate the effect of the interaction between the EOCC and different antibiotics and to evaluate its antibiofilm potential. The EOCC was obtained by hydrodistillation. Based on chemical characterisation, 70 compounds were identified, with 1.8 cineole (13.15%), p-cymene (10.68%), caryophyllene (9.73%) and spathulenol (6.36%) being the major constituents. The minimum inhibitory concentration (MIC) values of EOCC were 256 and 512 µg mL^-1 for methicillin-sensitive and -resistant Staphylococcus aureus strains (MSSA and MRSA), respectively. The combinations of EOCC with the antibiotics oxacillin and ampicillin were synergistic (OXA/EOCC and AMP/EOCC combined decreased the OXA MIC and AMP MIC to 0.5 and 0.25 for MSSA, respectively, and OXA/EOCC and AMP/EOCC combined decreased the OXA MIC and the AMP MIC to 1 and 0.5 for MRSA, respectively) and could modify the resistance profile of MSSA and MRSA strains. The results indicated that EOCC was also able to partially inhibit biofilm formation. Our study presents important information about the chemical composition of EOCC and its antimicrobial potential and provides a reference to determine the mechanisms of action of EOCC and its use in pharmaceutical formulations.

Keywords: Croton genus; Staphylococcus aureus; antibiofilm; knife breaker; resistance profile; volatile compounds.

Grants and funding

State University of Paraiba/UEPB, grant No. 003/2022. This study was financed in part by FAPESQ, Funding nº 04/2022—Support for the Scientific and Technological Development of the State of Paraíba—grant #3783/2022-0.