In vitro pharmacological evaluation of the antimicrobial, antioxidative, anti-inflammatory, and antibiofilm potential of carvacrol

Abstract Objectives Carvacrol is a phenolic monoterpenoid found in certain essential oils with a wide range of bioactivities. This study aimed to evaluate its in vitro cytotoxic, antioxidant, anti-inflammatory, antimicrobial, antibiofilm, and wound healing properties against resistant microbial strains and mammalian cells. Methods Carvacrol (18.75–300 μg/mL) was tested on BALB/c peritoneal macrophages, L929 fibroblasts, and resistant microbial strains. Cytotoxicity (3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide assay), antioxidant activity [reactive oxygen species (ROS) assay], and levels of NO, IL-6, and tumor necrosis factor-alpha (TNF-α) were measured. Antimicrobial activity was assessed by determining minimum inhibitory concentration (MIC), minimum bactericidal concentration, minimum fungicidal concentration, time-kill curves, membrane permeability, and antibiofilm assays. A scratch assay was used to evaluate fibroblast migration. Results Carvacrol was not cytotoxic at concentrations ≤150 μg/mL and significantly reduced ROS (by 86%), NO (by 98.58%), IL-6 (by 95.71%), and TNF-α (by 88%) at intermediate concentrations. The MICs of carvacrol for all bacterial strains were 100 μg/mL, with a bactericidal effect for Enterococcus faecalis and a bacteriostatic effect for Enterococcus faecium and Streptococcus oralis. In contrast, the MIC for Candida albicans was 200 μg/mL, with a fungistatic effect. An increase in membrane permeability was observed, with marked leakage of nucleotides and proteins. Carvacrol reduced mature biofilms more effectively than during the adhesion phase. At 9.38 μg/mL, its increased fibroblast migration by 20.34% in 24 h. Conclusion Carvacrol exhibited strong antimicrobial, antioxidant, and anti-inflammatory effects, with additional pro-migratory activity in fibroblasts in vitro.