Inhibition of the antioxidant activity of catalase and superoxide dismutase from Fusarium verticillioides exposed to a Jacquinia macrocarpa antifungal fraction

The aim of this study was to investigate the in vitro effect of an antifungal fraction obtained from Jacquinia macrocarpa plant (JmAF) in the generation of reactive oxygen species (ROS) and the activity of the catalase (CAT) and superoxide dismutase (SOD) enzymes from Fusarium verticillioides, as well as their influence in the viability of the fungus spores. The compounds present in the JmAF were determined by gas chromatography/quadrupole time-of-flight mass spectrometry (GC/QTOF-MS). The effect of the exposition to JmAF on the generation of ROS, as well as in the CAT and SOD activities in F. verticillioides, was determined. The main compounds detected were γ-sitosterol, stephamiersine, betulinol and oleic acid. JmAF showed very high ability in inhibiting the spore viability of F. verticillioides, and their capacity to cause oxidative stress by induction of ROS production. JmAF induced the highest ROS concentration and also inhibited CAT and SOD activities. The results obtained in this study indicate that JmAF is worthy of being considered for the fight against phytopathogenic fungi.     

Ultrastructural, Morphological, and Antifungal Properties of Micro and Nanoparticles of Chitosan Crosslinked with Sodium Tripolyphosphate

Recent studies have demonstrated the antibacterial effect of micro and nanoparticles of chitosan (CS) crosslinked with sodium tripolyphosphate (TPP), and incorporating metallic ions, bringing that the size, shape, and zeta potential are related to the antimicrobial potential. However, there are few studies on the antifungal activity and the effect of TPP on the antimicrobial potential. Micro and nanoparticles were prepared from CS by ionotropic gelation with TPP, and structurally characterized by transmission and scanning electron spectroscopy, and Fourier transformed infrared spectroscopy. Depending on the concentration of CS and TPP, spherical particles were obtained from 80 nm to 20 μm. Subsequently, particles were evaluated for their antifungal potential against Aspergillus parasiticus assessing radial growth, spore germination, and morphological changes. An increase in the antifungal potential compared with CS in solution was observed, inhibiting the development of the fungus causing clear morphological changes in both, hyphae and spores. Particle size and the availability of functional groups of CS/TPP (amino group and phosphate), suggest a possible synergistic effect between CS and TPP.     

Potentiation of antifungal effect of a mixture of two antifungal fractions obtained from Baccharis glutinosa and Jacquinia macrocarpa plants

The aim of the present work was to evaluate the effect of mixtures of antifungal fractions extracted from Baccharis glutinosa and Jacquinia macrocarpa plants on the development of the filamentous fungi Aspergillus flavus and Fusarium verticillioides. The minimal inhibitory concentration that inhibited 50% of growth (MIC₅₀) of each plant antifungal fraction was determined from the percentage radial growth inhibition of both fungi. Binomial mixtures made with both plant fractions were used at their MIC₅₀ to determine the Fractional Inhibitory Concentration index (FIC index) for each fungus in order to evaluate their synergistic effect. Each synergistic mixture was analyzed in their effect on spore germination, spore size, spore viability, mitotic divisions, hyphal diameter and length, and number of septa per hypha. Some antifungal mixtures, even at low concentrations, showed higher antifungal effect than those of the individual antifungal fraction. The FIC indices of mixtures that showed the highest antifungal activity against A. flavus and F. verticillioides were 0.5272 and 0.4577, respectively, indicating a synergistic effect against both fungi. Only 12% and 8% of the spores of A. flavus and F. verticillioides, respectively, treated with the synergistic mixtures, were able to germinate, although their viability was not affected. An increase in the number of septa per hypha of both fungi was observed. The results indicated that the synergistic mixtures strongly affected the fungal growth even at lower concentrations than those of the individual plant fractions.     

Phytotoxicity,cytotoxicity, and in vivo antifungal efficacy of chitosan nanobiocomposites on prokaryotic and eukaryotic cells

Environmental Science and Pollution Research - Chitosan (CS) nanosystems have potential applications for the control of microorganisms in the medical, environmental, and agrifood fields. In vivo...