RESUMO
Aims: The incidence of fungal infections has increased over the last ten years and fungi of the genus Penicillium can be found in various substrates and affect immunocompromised people, hospitalized patients, many animals and plants, as well as compromise the quality of air indoors. The current situation of indiscriminate use of antibiotics and the consequent resistance of microorganisms to conventional antimicrobial therapy has been stimulating researchers to seek alternative sources of antimicrobial compounds, among them the medicinal plants. The tendency of getting phytochemicals from extracts, fractions, fixed or essential oils obtained from plant species is currently observed. In this context, the present study aims to evaluate the in vitro antifungal activity of seven phytochemicals (geraniol, carvacrol, thymol, linalool, p-cymene, terpinolene and citral) against twelve samples of Penicillium. Place of Study: Laboratory tests were carried out at the Mycology Laboratory Department of Pharmaceutical Sciences, located in the Health Sciences Center (CCS) of the Federal University of Paraíba (UFPB). Methodology: Firstly, screening was carried out to find the phytochemical with the best activity by determining the minimum inhibitory concentration (MIC) by the broth microdilution technique. Following, the tests were proceeded with thymol to determine of minimum fungicidal concentration (MFC). Results: Through analysis of results, it is observed that carvacrol, thymol and citral showed the best activities of the samples of Penicillium studied. The MIC values were 256 mg / mL, for carvacrol and citral, and 128 mg / mL, for thymol (compound showed better results). The thymol had its MIC 90 established at 128 mg / mL, inhibiting, at this concentration, 92% of the tested samples. Analyzing compared to MIC and MFC, it was observed that thymol presented CFM values similar to CIM values for 1/3 of the samples, showing also values greater than 1024 mg / mL for only two samples. The CFM value ranged from 128 μg/ml to 1024 μg/ml. Conclusion: The thymol is a promising new possibility among the products with antifungal activity against Penicillium, however if the performance is needed further studies, deeper, about their mechanism of action and toxicity, as well as in vivo tests, aiming a possible application therapy.
RESUMO
Cladosporium carrionii is considered the most important pathogenic species of genus because of the numerous cases of disease which causes in the world. Due to its antifungal resistance, these fungal infections are difficult to treat. Given the broad biological activity displayed by natural products, essential oils obtained from plants are often investigated to determine their antimicrobial activity. Aims: Therefore, we identified components of Melissa officinalis L. essential oil, investigating in vitro antifungal activity against strains of C. carrionii. Methodology: Identification of the chemical composition of the oil was performed by gas chromatography coupled to a mass spectrometer (GC-MS). The antifungal activity of M. officinalis L. essential oil was investigated against 08 strains of C. carrionii determining minimum inhibitory concentration (MIC), minimum fungicidal concentration (MFC), effects on mycelial growth, and conidial germination. Results: The GC-MS results revealed 4 major components; geranial (52%), citral (38.90%), trans- β-caryophyllene (1.22%), and germacrene D (0.84%). M. officinalis L. essential oil inhibited the growth of all (100%) of the strains of C. carrionii tested. The MIC and MFC were established at 256 μg/ml. Inhibition of radial mycelial growth began at 128 μg/ml (MIC/2), and at both 2 x MIC and 4 x MIC the inhibition was complete. We also observed significant conidial germination inhibition at all concentrations when compared to the control (P<0.05). The inhibition increased with concentration so that at 2 x MIC complete (100%) conidia germination inhibition was observed. Conclusion: Finally, our study results point to M. officinalis L. essential oil as a potential antifungal agent against C. carrionii.