Extracting and evaluating the antibacterial activity of carvacrol from Plectranthus Amboinicus essential oil against Staphylococcus aureus and MRSA

Abstract

The essential oil of Plectranthus amboinicus was extracted through steam distillation. Carvacrol, the major constituent of the oil, was identified and found to make up 60.003% of the oil. Carvacrol was isolated using column chromatography with silica gel (200-430 mesh) and hexane: ethyl acetate (100:1) eluent solvent mixture, resulting in a high purity of 98.32%. Antimicrobial activity testing revealed that both Staphylococcus aureus and MRSA strains were sensitive to carvacrol and Plectranthus amboinicus essential oil (20 mg/mL). The antibacterial zone diameters were measured to be 20.20 ± 0.36 mm and 17.33 ± 0.32 mm for S. aureus, and 24.23 ± 0.47 mm and 21.53 ± 0.55 mm for MRSA, respectively. The minimum inhibitory concentration (MIC) of carvacrol against S. aureus and MRSA was determined to be 0.5 mg/mL. The minimum bactericidal concentration (MBC) against S. aureus was 1 mg/mL, while it was 0.5 mg/mL against MRSA.