Chemical composition, antioxidant and antibiofilm actions of Salvia rosmarinus and Plinia cauliflora extracts against endodontic pathogens and cytotoxicity on human Keratinocytes

Abstract The ongoing search for new endodontic irrigants is critical due to the persistence of resistant microorganisms within the root canal system. This study evaluated the hydroethanolic extracts of Salvia rosmarinus (rosemary) and Plinia cauliflora (jabuticaba) for their chemical composition, antioxidant activity, synergistic and antibiofilm effects against a clinical strain of Enterococcus faecalis and standard strains of Porphyromonas gingivalis and Fusobacterium nucleatum . Additionally, their cytotoxicity was tested on human keratinocytes (HaCaT). The extracts were prepared and filtered. The content of soluble solids, flavonoids, and phenols were quantified. High-performance liquid chromatography (HPLC) was performed later. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were evaluated. Then, the free radical suppressive (antioxidant) activity and the synergistic activity of the extract’s combination using checkerboard microdilution assay were evaluated. The most effective concentrations were analyzed against biofilms. Later, the cytotoxicity of the extracts was tested on human keratinocyte lines (HaCaT). Data were analyzed by the Kruskal Wallis and Dunn test (p ≤ 0.05). S. rosmarinus extract contained 9.48 mg/mL of soluble solids and was rich in caffeoylquinic and chlorogenic acids. P. cauliflora had 22.22 mg/mL of soluble solids, with gallic and ellagic acids as major compounds. Both extracts demonstrated antioxidant activity at 59 μg/mL for S. rosmarinus and 159 μg/mL for P. cauliflora . An additive antibacterial effect was observed against E. faecalis when 0.036 mg/mL of S. rosmarinus was combined with 2.77 mg/mL of P. cauliflora . Both extracts at low concentrations did not reduce the metabolic activity of HaCaT cells.