Antimicrobial, Cytotoxic, and Anti-Inflammatory Activities of Pimenta dioica and Rosmarinus officinalis Essential Oils

Abstract

Essential oils (EOs) are natural products composed of a mixture of volatile and aromatic compounds extracted from different parts of plants that have shown antimicrobial activities against pathogens. In this study, EOs extracted from Pimenta dioica (Myrtaceae) and Rosmarinus officinalis (Lamiaceae) were assessed for their antimicrobial activities using a panel of pathogenic Gram-positive, Gram-negative, and fungal strains. The antimicrobial activity was measured by the minimal inhibitory concentration required for the growth inhibition of the microorganisms. The cytotoxicity of the EOs was tested ex vivo using the model of human-derived macrophage THP-1 cells. In addition, an inflammatory response was evaluated using the anti-inflammatory cytokine IL-10 and the proinflammatory cytokines IL-6 and TNF-α. Results showed that both EOs had antimicrobial activity and different pathogens were exposed to concentrations ranging between 600 and 2000 μg/mL. In addition, the EOs showed no inflammatory activity when exposed to human macrophages, but a potent anti-inflammatory activity was measured when the oil from Rosmarinus officinalis was exposed to macrophages. This study demonstrates that the use of EOs is an effective alternative for pathogenic bacterial and fungal control, alone or in combination with antibiotic therapy. Moreover, the oil extracted from Rosmarinus officinalis could be used as potent anti-inflammatory agent.

Figure 1

Cytotoxicity of EO. The cytotoxicity of the (a) Pimenta dioica and (b) Rosmarinus officinalis EOs was assessed on human-derived macrophage THP-1 cell line using the MTT assay. PC: positive control. Shown is the mean ± S.D. of three independent experiments. ∗: P-value <0.05.

Figure 2

Immunological response of EO. The immunological response of the Pimenta dioica and Rosmarinus officinalis EOs was assessed on human-derived macrophage THP-1 cell line using ELISA for (a) IL-6, (b) IL-10, and (c) TNF-α. PD: Pimenta dioica. RO: Rosmarinus officinalis. LPS: lipopolysaccharide (positive control). Shown is the mean ± S.D. of three independent experiments. ∗: P-value <0.05.