Avaliação do potencial antitumoral, antioxidante e antimicrobiano do óleo essencial de Juniperus communis L. (Zimbro)

Abstract

Essential oils (OEs) in addition to having several pharmacological activities, are made up of volatile components, which, through inhalation, can be delivered directly to the tissues of the respiratory tract. This property makes it interesting to investigate the effects of its vapor phase by comparing them with the liquid phase in the treatment of diseases using this route. The objective of this work was to evaluate the antitumor, antioxidant and antimicrobial potential of the EO of Juniperus communis L. (juniper) in its liquid (LP) and vapor (VP) phases. As an experimental strategy, NCI-H292 cells from lung carcinoma and MRC-5 cells from lung fibroblasts (control) were used in assays to assess their antitumor potential. Treatments with EO were carried out for a period of 24 hours with FL (5-2000 μg/mL/well) and with VP (25-16000 μg/mL/well).

Cell viability was determined by (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H- tetrazolium bromide) (MTT) reduction assays and protein staining with sulforhodamine

B (SRB), from which IC50 values and selectivity index (SI) were calculated, in addition the Scratch assay was performed to assess cell proliferation. Both phases of the EO reduced the viability of the tumor lineage in a dose-dependent manner. In the MTT and SRB assays, the respective IS values of 4.43 and 5.32 μg/mL were obtained for LP and >20 and 7.01 μg/mL for VP. The Scratch assay showed a reduction in cell proliferation by 66% and 35.7% for LP and VP respectively. For the reactive oxygen species (ROS) detection tests, the compound DCFH-DA was used in order to evaluate the antioxidant potential of the EO. This assay, when using non-cytotoxic concentrations, indicated that EO, in both phases, increased the basal production of intracellular ROS of the J774 macrophage lineage. However, in the presence of hydrogen peroxide, EO reduced EROS production. The evaluation of the antimicrobial activity of the LP of the EO was carried out against the strains of S. aureus, K. pneumoniae, and C. albicans 10231 and 14053, submitted to macrodilution assays in broth at concentrations of 31.25-4000 μg/mL. For VP, microatmosphere tests were performed using the MIC50 values obtained from the previous test. In the macrodilution assays, the MIC50 values obtained were 1000, 1000, 250 and 500 μg/mL for S. aureus, K. pneumoniae, C. albicans 10231 and C. albicans 14053, respectively, and the MIC90 values were obtained only with the fungal strains. In the microatmosphere assays for VP, only the two strains of C. albicans demonstrated the formation of zone/halo of growth inhibition, with a diameter between 3.5mm and 3.8mm. From the pre-selection of ATCC strains with greater sensitivity, clinical oral strains of C. albicans were tested to compare the effect of EO. In only one of these strains (34C) there was a reduction in viability with a strong effect of juniper EO on LP (MIC50 of 250 μg/mL) and an inhibition zone of 4.7 mm on VP. In conclusion, the results obtained indicate that both phases of the juniper EO have antitumor and antioxidant effects (in stimulated cells), both being more expressive in LP. LP and VP also have antimicrobial effects, however, respectively, moderate and low. Considering the therapeutic potential of the EO revealed in this study and the possibility of using the alternative route of administration of the vapor phase, the inhalation, it becomes important to investigate the possible mechanisms of action of this EO.