Antifungal and antiaflatoxigenic activity of rosemary essential oil (Rosmarinus officinalis L.) against Aspergillus flavus.

The increased risk to health by diverse pathologies, such as cancer, liver diseases, and endocrine alterations, caused by chemical residues in food, has led to the search for sustainable agricultural management alternatives, such as the use of essential oils for the development of natural and eco-friendly fungicides. The aim of this study was to evaluate the antifungal and antiaflatoxigenic activity of Rosmarinus officinalis L. essential oil (REO) against Aspergillus flavus Link. REO was obtained by hydrodistillation and its major components were identified as 1,8-cineole (eucalyptol, 52.2%), camphor (15.2%) and α-pinene (12.4%) by GC/MS and NMR. The minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) were both 500 µg/mL. REO reduced the mycelial growth of A. flavus at a concentration of 250 µg/mL (15.3%). The results obtained from scanning electron microscopy (SEM) demonstrated a reduction in the size of conidiophores and in the thickness of hyphae in A. flavus caused by treatment with REO (250 µg/mL). The production of ergosterol and the biomass of mycelium were both reduced as the REO treatment concentration increased. The production of aflatoxins B1 and B2 was inhibited after treatment with 250 µg/mL REO, a concentration below the MIC/MFC, indicating that the antiaflatoxigenic effect of REO is independent of its antifungal effect and is likely due to its direct action upon toxin biosynthesis. The data demonstrated that REO may be used as an alternative to synthetic fungicides.

Antifungal activity and inhibition of fumonisin production by Rosmarinus officinalis L. essential oil in Fusarium verticillioides (Sacc.) Nirenberg.

The chemical composition of Rosmarinus officinalis L. essential oil (REO) was analysed by gas chromatography-mass spectrometry and nuclear magnetic resonance spectroscopy. The main compounds of the REO were 1.8 cineole (52.2%), camphor (15.2%) and α-pinene (12.4%). The mycelial growth of Fusarium verticillioides (Sacc.) Nirenberg was reduced significantly by 150 µg/mL of REO. Significant microscopic morphological changes were visualised, such as the rupture of the cell wall and the leakage of cytoplasm at 300 µg/mL of REO. At lower concentrations of REO, the effects on the production of ergosterol and the biomass of mycelium varied, as did the effects on the production of fumonisins, but at ≥300 µg/mL of REO, these processes were significantly inhibited, showing the effectiveness of the REO as an antifungal agent. The results suggested that the REO acts against F. verticillioides by disrupting the cell wall and causing the loss of cellular components, subsequently inhibiting the production of fumonisins and ergosterol.

Antifungal properties and inhibitory effects upon aflatoxin production of Thymus vulgaris L. by Aspergillus flavus Link.

The antifungal and antiaflatoxigenic properties of Thymus vulgaris essential oil (TEO) were evaluated upon Aspergillus flavus "in vitro". Suspension containing 10(6) of A. flavus were cultivated with TEO in concentrations ranging from 50 to 500 µg/mL. TEO reached minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) at 250 µg/mL. Inhibition of ergosterol biosynthesis was detected at a concentration of 100 µg/mL of TEO. Morphological evaluation performed by both light microscopy and scanning electron microscopy showed that antifungal activity of TEO could be detected starting at a concentration of 50 µg/mL and the fungicide effect at a concentration of 250 µg/mL. TEO completely inhibited production of both B1 and B2 aflatoxins (AFB1 and AFB2) at a concentration of 150 µg/mL. This way, fungal biomass development and aflatoxin production were dependent on TEO concentration. Therefore, TEO was capable of controlling the growth of A. flavus and its production of aflatoxins.

Effect of Zingiber officinale essential oil on Fusarium verticillioides and fumonisin production.

The antifungal activity of ginger essential oil (GEO; Zingiber officinale Roscoe) was evaluated against Fusarium verticillioides (Saccardo) Nirenberg. The minimum inhibitory concentration (MIC) of GEO was determined by micro-broth dilution. The effects of GEO on fumonisin and ergosterol production were evaluated at concentrations of 500-5000 µg/mL in liquid medium with a 5mm diameter mycelial disc of F. verticillioides. Gas chromatography-mass spectrometry showed that the predominant components of GEO were α-zingiberene (23.9%) and citral (21.7%). GEO exhibited inhibitory activity, with a MIC of 2500 µg/mL, and 4000 and 5000 µg/mL reduced ergosterol biosynthesis by 57% and 100%, respectively. The inhibitory effect on fumonisin B1 (FB1) and fumonisin B2 (FB2) production was significant at GEO concentrations of 4000 and 2000 µg/mL, respectively. Thus, the inhibition of fungal biomass and fumonisin production was dependent on the concentration of GEO. These results suggest that GEO was able to control the growth of F. verticillioides and subsequent fumonisin production.

Isolamento, viabilidade em baixas temperaturas e cultivo axênico de cistos de Giardia duodenalis em pacientes da região noroeste do Paraná / Isolation, viability in low temperatures and axenic culture of cysts of Giardia duodenalis of patients of the region the northwest of the Paraná

A giardiose é um grande problema de saúde pública. O objetivo deste trabalho foi isolar cistos de Giardia duodenalis a partir de fezes humanas, verificar a viabilidade dos cistos em função do tempo de estocagem embaixa temperatura e promover o desencistamento para obtenção de trofozoítos para cultura axênica. Os cistosforam isolados e purificados, de acordo com a técnica de Roberts-Thompson et al. As amostras foram divididas em duas partes, uma das partes foi utilizada para verificar a viabilidade dos cistos estocados à baixa temperatura, e a outra foi submetida à axenização, desencistamento e cultivo. Para o desencistamento,utilizaram-se as técnicas de Bingham-Meyer e de Feely et al. A viabilidade dos cistos em função do tempo deestocagem em baixa temperatura decresceu com o tempo de armazenamento. Não foram observadas mudanças estatisticamente significativas na viabilidade das amostras isoladas, após 24, 48, 72 horas e nos dois meses seguintes. Do terceiro ao quinto mês, houve decréscimo na porcentagem de cistos viáveis e, nonono mês, perda total da viabilidade. Não foi observado crescimento in vitro das amostras axenizadas. Este estudo poderá contribuir para expandir os conhecimentos deste parasito e, posteriormente, auxiliar na detecção de diferenças entre cepas.

Giardiosis is a serious public health problem. The objective of this work was to isolate cysts of Giardia duodenalis taken from human stools, in order to verify the viability of the cysts in function of the time ofstockage in low temperature, as well as to obtain trophozoites for axenic culture. The isolated cysts were isolated and purified using the technique of Roberts-Thompson et al. The samples were divided in two groups; one was used to verify the viability of the stored cysts in low temperature, while the other was submitted toaxenization, excystation and culture. For excystation, two techniques were used. The viability of the cysts’stockage in low temperature decreased with storage time. Statistically significant changes in the viability of theisolated samples were not observed after 24, 48, 72 hours, and in the following two months. From the third tothe fifth month, there was a decrease in the percentage of viable cysts, and the ninth month total loss of viability occurred. Growth in vitro of the axenic samples was not observed. This study will be able to contribute to expanding the knowledge of this parasite and, later aid in the detection of differences between types.

La giardiosis es un gran problema de salud pública. El objetivo de este trabajo fue aislar quistes de Giardia duodenalis a partir de los excrementos de seres humanos, verificar la viabilidad de los quistes en función deltiempo de almacenamiento en baja temperatura y promover el desenquistamiento para la obtención detrofozoitos para la cultura axénica. Los quistes fueron aislados y purificados, de acuerdo con la técnica deRoberts-Thompson et. al. Las muestras fueron divididas en dos partes, una de las partes fue utilizada paraverificar la viabilidad de los quistes mantenidos en bajas temperaturas, y otra fue sometida al axenización, al desenquistamiento y cultivo. Para el desenquistamiento, se utilizaron las técnicas de Bingham-Meyer y de Feelyet. al. La viabilidad de los quistes en función del tiempo de mantenimiento en baja temperatura disminuyó conel tiempo de almacenamiento. No fueron observados cambios estadísticamente significativos en la viabilidad delas muestras aisladas, después de 24, 48, 72 horas y en los dos meses siguientes. Del tercero al quinto mes, hubo una disminución del porcentaje de quistes viables y, en el noveno mes, ocurrió pérdida total de laviabilidad. No fue observado crecimiento in vitro de las muestras axenizadas. Este estudio podrá contribuir para ampliar los conocimientos de este parásito y, más adelante auxiliar en la detección de diferencias entre cepas.