The Efficiency of Deoxynivalenol Degradation by Essential Oils under In Vitro Conditions.

Essential oils (EOs) are complex natural products of plant origin and exhibit different desirable, e.g., antimicrobial properties. Their growth inhibition effect on the pathogenic fungi of the genus, Fusarium, which forms deoxynivalenol (DON), has been documented. DON is the most common contaminant of grains and their products, causing strong emetic effects after their consumption. The aim of the study was to investigate the ability of selected EOs to degrade DON under in vitro conditions, using various incubation terms. The impact of a different temperature, pH, incubation time, mycotoxin, and essential oil concentration was tested. The results indicate that the kind of EO influences the effectiveness of mycotoxin level reduction, and the most effective EOs were palmarosa and lemon oils. A higher reduction of DON content by EOs was achieved after 24 h of the experiment (up to 72%), at a pH range between 3 and 6 and a temperature of 20 °C. Moreover, the effect of various doses of white and pink grapefruit and palmarosa EOs (100 and 200 µL/mL) on toxin level reduction was observed. The experiment confirmed that the selected EOs may be effective in DON reduction, as previously documented in experiments with zearalenone.

Antifungal activity of selected essential oils against Fusarium culmorum and F. graminearum and their secondary metabolites in wheat seeds.

Essential oils (EOs) are products of plant origin and include mixtures of different chemical compounds. These volatile substances have many interesting properties, including antifungal properties. Fungi may develop under field conditions on crops such as wheat or corn and are able to synthesize mycotoxins, which adversely affect livestock and human health. In the present study, selected EOs were used to inhibit the growth of Fusarium graminearum and F. culmorum and reduce the concentrations of mycotoxins in wheat grain. The EOs significantly inhibited the growth of tested Fusarium species (90.99-99.99%), as determined based on ergosterol quantitative analysis. Only the addition of orange oil to F. culmorum exhibits a different inhibition capacity (68.13%). EO application resulted in a large reduction in zearalenone content (99.08-99.99%); only in the case of orange oil application was the reduction estimated at approximately 68.33%. However, all EOs provided a significant reduction in the concentration levels of group B trichothecenes (94.51-100%). It can be concluded that EOs inhibit the growth of fungi of the genus Fusarium and reduce concentration levels of the mycotoxins zearalenone and group B trichothecenes.

The Inhibitory Potential of Selected Essential Oils on Fusarium spp. Growth and Mycotoxins Biosynthesis in Maize Seeds.

Owing to their rich chemical composition, essential oils (EOs) have many interesting properties, including antimicrobial activities. The presence of Fusarium and their secondary metabolites, mycotoxins, in cereal crops is a serious problem in agriculture, which consequently affects food quality. The aim of the present study was to investigate the effects of selected EOs on the growth of Fusarium graminearum and F. culmorum and the biosynthesis of mycotoxins in maize seeds. Chromatographic analysis of ergosterol as a fungal growth indicator showed a significant inhibition of Fusarium growth (83.24-99.99%) compared to the control samples, which as a consequence resulted in a reduction in mycotoxin concentrations. The addition of cinnamon, palmarosa, orange, and spearmint EOs was shown to be the most effective in reducing zearalenone concentration (99.10-99.92%). Deoxynivalenol analysis confirmed a very high reduction of this compound at the application all tested EOs (90.69-100%). The obtained results indicated that EOs have a great potential to inhibit growth of Fusarium fungi as well as reduce the concentration of mycotoxins in maize seed.

Degradation of Zearalenone by Essential Oils under In vitro Conditions.

Essential oils are volatile compounds, extracted from plants, which have a strong odor. These compounds are known for their antibacterial and antifungal properties. However, data concerning degradation of mycotoxins by these metabolites are very limited. The aim of the present study was to investigate the effect of essential oils (cedarwood, cinnamon leaf, cinnamon bark, white grapefruit, pink grapefruit, lemon, eucalyptus, palmarosa, mint, thymic, and rosemary) on zearalenone (ZEA) reduction under various in vitro conditions, including the influence of temperature, pH, incubation time and mycotoxin and essential oil concentrations. The degree of ZEA reduction was determined by HPLC method. It was found that the kind of essential oil influences the effectiveness of toxin level reduction, the highest being observed for lemon, grapefruit, eucalyptus and palmarosa oils, while lavender, thymic and rosemary oils did not degrade the toxin. In addition, the decrease in ZEA content was temperature, pH as well as toxin and essential oil concentration dependent. Generally, higher reduction was observed at higher temperature in a wide range of pH, with clear evidence that the degradation rate increased gradually with time. In some combinations (e.g., palmarosa oil at pH 6 and 4 or 20°C) a toxin degradation rate higher than 99% was observed. It was concluded that some of the tested essential oils may be effective in detoxification of ZEA. We suggested that essential oils should be recognized as an interesting and effective means of ZEA decontamination and/or detoxification.

The impact of polyphenols on Bifidobacterium growth.

Polyphenols are a common group of plant based bioactive compounds, that can affect human health because of their antioxidant and antimicrobial properties as well as free-radical scavenging activity. An increasing interest is observed in the interaction between polyphenols and microbiota occurring in food and the human gut. The aim of the work presented here, was to evaluate the effect of some polyphenolic compounds on the growth of two strains of Bifidobacterium: B. adolescentis and B. bifidum. The influence of some flavonoids: naringinin, hesperidin, rutin, quercetin as well as phenolic acids: gallic, caffeic, p-coumaric, ferulic, chlorogenic, vanillic and sinapic was determined by a 96-well microtiter plate assay. In the experiments the effect of three different concentrations of polyphenols: 2, 20 and 100 µg/ml on the growth of Bifidobacterium strains was investigated. All tested compounds influenced the growth of the examined bacteria. Both stimulatory and inhibitory effects were observed in comparison to the positive control. The strongest impact on the growth of bifidobacteria was observed during the first hours of incubation. The constant inhibitory effect was observed for hesperidin and quercetin addition and was dose-dependent. B. bifidum showed a stronger dependence on phenolic acids content in the medium than B. adolescentis during the first hours of incubation.