Revista Mexicana de Micología Antifungal activity of methanolic extracts of Jacquinia macrocarpa and Krameria erecta on the growth of Fusarium verticillioides and effect on fumonisin production

Actividad antifúngica de extractos metanólicos de Jacquinia macrocarpa y Krameria erecta en el crecimiento de Fusarium verticillioides y su efecto en la producción de fumonisinas RESUMEN Algunas plantas medicinales han sido estudiadas sobre hongos fitopatógenos para conocer si tienen propiedades antifúngicas, por ello en este estudio se evaluaron los extractos metanólicos de hojas de Jacquinia macrocarpa y Krameria erecta sobre el crecimiento radial, germinación de esporas y producción de biomasa por Fusarium moniliforme en medio agar papa dextrosa. El extracto de J. macrocarpa que presentó mejores resultados fue particionado con hexano, acetato de etilo y n-butanol. Solo la fracción butanólica presentó actividad, ya que retardó la germinación de esporas y el crecimiento de las colonias cambió de radial a apical, que indica que el hongo está estresado. La producción de fumonisina no fue afectada por el extracto. Se concluye que el extracto metanólico de J. macrocarpa y su fracción butanólica son capaces de retardar el crecimiento de F. verticillioides in vitro y no afectan la producción de fumonisinas. PALABRAS CLAVE: germinación de esporas, crecimiento radial, micotoxinas. ABSTRACT Some medicinal plants have been studied on phytopathogenic fungi for their antifungal activity. For this reason the goal of this study was to evaluate methanolic extract of Jacquinia macrocarpa and Krameria erecta on radial growth, spore germination, biomass production of Fusarium verticillioides. Methanolic extract of J. macrocarpa which caused the best results was sequentially partitioned with hexane, ethyl acetate and n-butanol. Only the butanolic fraction was active. It delayed the spore germination and the colony growth changed from radial to apical, which is a way to express it is under pressure due to chemicals present in the fraction. Fumonisin production was not affected by the extract. We conclude that J. macrocarpa methanolic extract and its butanolic fraction are capable to delay the radial growth of F. verticillioides and the kinetic of spore germination and do not affect fumonisin production

Revista Mexicana de Micología Antifungal activity of methanolic extracts of Jacquinia macrocarpa and Krameria erecta on the growth of Fusarium verticillioides and effect on fumonisin production Revista Mexicana de Micología Antifungal activity of methanol

Actividad antifúngica de extractos metanólicos de Jacquinia macrocarpa y Krameria erecta en el crecimiento de Fusarium verticillioides y su efecto en la producción de fumonisinas RESUMEN Algunas plantas medicinales han sido estudiadas sobre hongos fitopatógenos para conocer si tienen propiedades antifúngicas, por ello en este estudio se evaluaron los extractos metanólicos de hojas de Jacquinia macrocarpa y Krameria erecta sobre el crecimiento radial, germinación de esporas y producción de biomasa por Fusarium moniliforme en medio agar papa dextrosa. El extracto de J. macrocarpa que presentó mejores resultados fue particionado con hexano, acetato de etilo y n-butanol. Solo la fracción butanólica presentó actividad, ya que retardó la germinación de esporas y el crecimiento de las colonias cambió de radial a apical, que indica que el hongo está estresado. La producción de fumonisina no fue afectada por el extracto. Se concluye que el extracto metanólico de J. macrocarpa y su fracción butanólica son capaces de retardar el crecimiento de F. verticillioides in vitro y no afectan la producción de fumonisinas. PALABRAS CLAVE: germinación de esporas, crecimiento radial, micotoxinas. ABSTRACT Some medicinal plants have been studied on phytopathogenic fungi for their antifungal activity. For this reason the goal of this study was to evaluate methanolic extract of Jacquinia macrocarpa and Krameria erecta on radial growth, spore germination, biomass production of Fusarium verticillioides. Methanolic extract of J. macrocarpa which caused the best results was sequentially partitioned with hexane, ethyl acetate and n-butanol. Only the butanolic fraction was active. It delayed the spore germination and the colony growth changed from radial to apical, which is a way to express it is under pressure due to chemicals present in the fraction. Fumonisin production was not affected by the extract. We conclude that J. macrocarpa methanolic extract and its butanolic fraction are capable to delay the radial growth of F. verticillioides and the kinetic of spore germination and do not affect fumonisin production

Antifungal and antimycotoxigenic activity of essential oils from Eucalyptus globulus, Thymus capitatus and Schinus molle

Abstract Essential oils (EO) of eucalyptus (Eucalyptus globulus L.), thymus (Thymus capitatus L.) pirul (Schinus molle L.) were evaluated for their efficacy to control Aspergillus parasiticus and Fusarium moniliforme growth and their ability to produce mycotoxins. Data from kinetics radial growth was used to obtain the half maximal inhibitory concentration (IC50). The IC50 was used to evaluate spore germination kinetic and mycotoxin production. Also, spore viability was evaluated by the MTT assay. All EO had an effect on the radial growth of both species. After 96 h of incubation, thymus EO at concentrations of 1000 and 2500 µL L–1 totally inhibited the growth of F. moniliforme and A. parasiticus, respectively. Eucalyptus and thymus EO significantly reduced spore germination of A. parasiticus. Inhibition of spore germination of F. moniliforme was 84.6, 34.0, and 30.6% when exposed to eucalyptus, pirul, and thymus EO, respectively. Thymus and eucalyptus EO reduced aflatoxin (4%) and fumonisin (31%) production, respectively. Spore viability was affected when oils concentration increased, being the thymus EO the one that reduced proliferation of both fungi. Our findings suggest that EO affect F. moniliforme and A. parasiticus development and mycotoxin production

Control of mycotoxigenic fungi with microcapsules of essential oils encapsulated in chitosan

Abstract Aspergillus and Fusarium are the fungi genera most frequently isolated from cereal grains and other commodities. They are capable of producing mycotoxins, which can affect the human and animal health. Synthetic fungicides have been used to control these fungi, nevertheless, they have acquired resistance and other alternatives are necessary since they now need higher amounts. Therefore, the aim of this study was to evaluate the efficacy of cinnamon, clove and thyme essential oils (EOs) alone and encapsulated in chitosan on the radial growth, spore germination and mycotoxin production by Fusarium verticillioides and Aspergillus parasiticus. The composition of the EOs was determined by gas chromatography mass spectrometry (GC-MS). EOs inhibited radial growth and spore germination of both fungal species better than when they were encapsulated, plus, they reduced mycotoxin production. The major components were eugenol in cinnamon and clove EO (70 and 63%, respectively) and 2-methyl-5-(1-methyethyl)-phenol (46.2%) in thyme EO. The microparticles with clove and thyme EO showed good surface charges, higher than +30 mV and their average size for the three types of microparticles was about 750 nm. Our findings suggest that EOs both alone and encapsulated in chitosan have a fungistatic effect on Fusarium verticillioides and Aspergillus parasiticus

Enhanced Antifungal Effect of Chitosan/Pepper Tree (Schinus molle) Essential Oil Bionanocomposites on the Viability of Aspergillus parasiticus Spores

Chitosan nanoparticles (CS) and chitosan/pepper tree (Schinus molle) essential oil (CS-EO) bionanocomposites were synthesized by nanoprecipitation method and the in vitro antifungal activity against Aspergillus parasiticus spores was evaluated. The shape and size were evaluated by scanning electron microscopy (SEM) and dynamic light scattering (DLS). The surface charge was determined by assessing the zeta potential and the inclusion of essential oil in bionanocomposites using Fourier transform infrared spectroscopy (FT-IR). The effect on cell viability of the fungus was evaluated using the XTT technique and morphometric analysis by image processing. SEM and DLS analysis indicated that spherical particles with larger diameters for CS-EO biocomposites were observed. Zeta potential values were higher (+11.1 ± 1.60 mV) for CS nanoparticles. Results suggest a chemical interaction between chitosan and pepper tree essential oil. The highest concentration of CS-EO complex caused a larger (40–50%) decrease in A. parasiticus viability. The inclusion of pepper tree oil in CS nanoparticles is a feasible alternative to obtain antifungal biocomposites, where the activity that each compound presents individually is strengthened

Relationship between the Antifungal Activity of Chitosan–Capsaicin Nanoparticles and the Oxidative Stress Response on Aspergillus parasiticus

The fungus Aspergillus parasiticus is a contaminant in agricultural crops and its eradication involves the indiscriminate use of harmful synthetic pesticides. In the search for antifungal agents of natural origin, chitosan (Q) and capsaicin (C) are coupled in the form of nanoparticles (Np), which can possess a direct application under specific conditions. Due to their small size, Np can cross through the cell wall, taking the cells into a pro-oxidant environment known as “oxidative stress”, which presents when the reactive oxygen species (ROS) surpass the number of antioxidants in the cell. In the present investigation, nanoparticles of chitosan (Np Q) and nanoparticles of chitosan-capsaicin (Np QC) with an average diameter of 44.8 ± 20.6 nm and 111.1 ± 14.1 nm, respectively, were synthesized, and there was a zeta potential of + 25.6 ± 0.7 mV and + 26.8 ± 6.1 mV, respectively. The effect of the concentration of Np Q (A, B, C, and D), of Np QC (A, B, C, and D), and capsaicin in a solution (control) was evaluated on the viability of the spores, the accumulation of intracellular ROS, and the morphometric changes of A. parasiticus. Acute toxicity of the Np was determined utilizing bioassays with Artemia salina, and acute phytotoxicity was evaluated in lettuce seeds (Lactuca sativa). According to ROS results, capsaicin (control) did not induce oxidative stress in the cell; otherwise, it was observed to have an elevated (p < 0.05) accumulation of ROS when the concentration of Np Q increased. For both, Np Q and Np QC, an inverse physiological pattern relating spore viability and ROS accumulation in the fungus was found; the viability of spores decreased as the ROS accumulation increased. The spore viability of A. parasiticus diminished upon increasing the concentration of chitosan (0.3–0.4 mg/mL) in the Np, while the intracellular accumulation of ROS increased proportionally to the concentration of the nanomaterials in the treatments of Np Q and Np QC. On the other hand, Np QC presented a lower (p < 0.05) toxicological effect in comparison with Np Q, which indicates that the incorporation of bioactive compounds, such as capsaicin, into nanoparticles of chitosan is a strategy that permits the reduction of the toxicity associated with nanostructured materials