Potencial antioxidante, antitumoral e antifúngico de constituintes de óleos essenciais

Abstract

Natural products are important sources of discovery of new medicinal agentes, and it is necessary to perform studies that enable their application because of the biological and pharmacological potential of these compounds. The objective of this study was to evaluate the antioxidant potential of constituents of essential oils by different methods to study the antitumor potential of these compounds against human cancer cell lines, as well as to evaluate the antifungal potential of certain constituents. The antioxidant tests were evaluated by methods that involve the stabilization of free radicals, inhibition of lipid peroxidation and complexation of metals. Antitumor tests were performed on three cell lines derived from human tumors: MCF-7, A549, and HT144. Cell viability was measured by the colorimetric assay using the resazurin dye. For the determination of the cell populations in the different phases of the cell cycle, the DNA content was analyzed by flow cytometry. The evaluation of the inhibitory effect of p-cymene, eugenol, carvacrol, citral, trans-caryophyllene and transfarnesol on the Aspergillus carbonarius, Aspergillus flavus, Aspergillus ochraceus and Aspergillus niger fungi was achieved using the disc diffusion method. The effect of eugenol, carvacrol and citral on the mycelial growth of A. carbonarius and A. niger fungi at different temperatures was evaluated. In general, the compounds presented low antioxidant activities, except for carvacrol, thymol and eugenol, which were more active in the methods tested. Expressive inhibition of the cellular viability of the tumor cell lines was observed for the constituents carvacrol, thymol, citral and eugenol. The IC 50 values found for citral demonstrated a better response to the HT144 lineage. The compound induced cell cycle blockage in the G1/S transition, but it did not stimulate cell death. Analysis of inhibitory activity against the fungus revealed that the eugenol, carvacrol and citral compounds possessed a greater ability to inhibit the growth of the microorganisms evaluated. These constituents also influenced the mycelial growth of the A. niger and A. carbonarius fungi at different temperatures, and temperatures of 20 ºC and 25 ºC were more favorable for fungal development. The results found were promising in the search for bioactive compounds. Studies involving these constituents in other activities, as well as in association with synthetic compounds that are already employed to decrease their toxicities and resistance and to evaluate synergistic effects, might be relevant.