Atividade antifúngica do óleo essencial de Lippia grata Schauer (Verbenaceae) frente Candida albicans e dermatófitos
Species of the genus Candida are responsible for about 80% of serious fungal infections, being Candida albicans the most commonly isolated species in these cases, and it is also frequently associated with cutaneous and mucocutaneous fungal infections. Among the filamentous fungi responsible for c...
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| Formato: | Dissertação |
| Idioma: | pt_BR |
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Universidade Federal do Rio Grande do Norte
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| Endereço do item: | https://repositorio.ufrn.br/handle/123456789/55256 |
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| Resumo: | Species of the genus Candida are responsible for about 80% of serious fungal infections,
being Candida albicans the most commonly isolated species in these cases, and it is also
frequently associated with cutaneous and mucocutaneous fungal infections. Among the
filamentous fungi responsible for cutaneous mycoses in humans, dermatophytes, a group of
crosely related fungi, affect 25% of the world population. Furthermore, both Candida and
dermatophyte species have shown resistance to antifungal drugs. In this context, it is
perceived an incessant search of the scientific community for molecular prototypes that
present antifungal potential, such as those of plant origin, due to their many antimicrobial
properties described in the literature. Therefore, the present proposal aims to evaluate the
antifungal activity of the essential oil from the plant Lippia grata Schauer (Verbenaceae)
against Candida albicans and different species of dermatophyte fungi. The essential oil was
obtained from the hydrodistillation process, with subsequent analysis of percentage content
(%) and phytochemistry by gas chromatography associated with mass spectrometry. The
bioactivity of the essential oil obtained from the plant Lippia grata was investigated on 26
fungal samples by the method of Minimum Inhibitory Concentration (MIC) by the
microdilution broth technique and Minimum Fungicidal Concentration (MFC) using solid
medium, while the synergistic activity was evaluated using the “checkerboard” method. The
quantification tests of biofilm production and antibiofilm activity of Lippia grata essential oil
were performed using crystal violet to measure the optical densities obtained. The yield of
essential oil of Lippia grata was 2.45%. Four main phytoconstituents were identified in the
chemical characterization of Lippia grata essential oil: carvacrol (51.4%) as the majority
constituent, thymol (15.6%), ρ-cymene (12.2%) and γ-terpinene (7.4%). Antifungal activity of
Lippia grata essential oil was found for 100% of the tested strains with MIC and MFC
ranging from 390.62 µg/mL to 3.125 µg/mL against Candida albicans strains. For
dermatophytes, the MIC ranged from 48.82 µg/mL to 390.62 µg/mL, while the MFC ranged
from 48.82 µg/mL a 781.25 µg/mL. Regarding the evaluation of the effect of combinations of
drugs, synergistic (50%) and additive (50%) interactions were observed on the strains tested.
The results of biofilm formation revealed that 100% of the strains were biofilm producers. For
Candida albicans strains, 4 (22.22%) were weak producing strains, 7 (38.88%) moderate
producing strains and 7 (38.88%) strong producing strains. For dermatophyte strains, 2 (25%)
moderate producing strains and 6 (75%) were strong producing strains. For the antibiofilm
activity of the essential oil, it was verified inhibition of biofilm ranging from 28.8.% to 72.4%
for Candida albicans strains and 4.39% to 90.4% for dermatophytes, when these strains were
post-treated, respectively, with concentrations of 2xCIM, CIM e 2/CIM of Lippia grata
essential oil. It was concluded that the essential oil of Lippia grata showed antifungal activity,
motivating new studies with the intention of future development of phytodrugs directed to the
treatment of fungal infections. |
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