Chitosan coatings on lecithin stabilized emulsions inhibit mycotoxin production by Fusarium pathogens

Chitosan coated clove oil-based nanoemulsion: An attractive option for oral delivery of leflunomide in rheumatoid arthritis

Rheumatoid arthritis (RA), a distressing inflammatory autoimmune disease, is managed mainly by Disease-modifying antirheumatic drugs (DMARDs), e.g. leflunomide (LEF). LEF (BCS class II) has limited solubility and adverse effects following its systemic exposure. The appealing antirheumatic properties of both clove oil and chitosan (CS) were exploited to design oral leflunomide (LEF)-loaded nanoemulsion (NE) system to augment the therapeutic action of LEF and decrease its systemic side effects as well. Different LEF-NEs were prepared using clove oil, Tween® 20 (surfactant), and PEG 400(co-surfactant) and characterized by thermodynamic stability, percentage transmittance, cloud point, size analysis, and drug content. Optimized LEF-NE was subjected to CS coating forming LEF-CS-NE that exhibited nanometric size range, prolonged drug release, and good physical stability. In vivo anti-rheumatic activity of pure LEF, market LEF, and LEF-CS-NE was assessed utilizing a complete Freund's adjuvant (CFA) rat model. Treatment with LEF-CS-NE reduced edema rate (48.68% inhibition) and caused a marked reduction in interleukin-6 (IL-6) (510.9 ± 2.48 pg/ml), tumor necrosis factor- α (TNF-α) (397.3 ± 2.53 pg/ml), and rheumatoid factor (RF) (42.58 ± 0.49 U/ml). Furthermore, LEF-CS-NE reduced serum levels of glutamic pyruvic transaminase (GPT) to (83.19%) and glutamic oxaloacetic transaminase (GOT) to (40.68%) compared to the control + ve group. The effects of LEF-CS-NE were also superior to both pure and market LEF and showed better results in histopathological studies of paws, liver, kidney, lung, and heart. The remarkable therapeutic and safety profile of LEF-CS-NE makes it a potential oral system for the management of RA.

Low Molecular Weight and High Deacetylation Degree Chitosan Batch Alleviates Pathogenesis, Toxin Accumulation, and Fusarium Gene Regulation in Barley Leaf Pathosystem

Fusarium graminearum is a cosmopolitan fungal pathogen that destroys cereal production, in terms of loss of yield and grain contamination with mycotoxins, worldwide. Chitosan is a natural biopolymer abundant in the environment with proven antifungal properties that also acts as a plant immunity elicitor. Despite a number of articles, there is a lack of systematic comparison of antifungal activity of diverse batches of chitosan. The current study aimed to test the inhibitory effects of a collection of diverse chitosan samples on the growth and production of F. graminearum toxins, validated by changes in the Fusarium transcriptome. Experiments included testing antifungal activity of different chitosan samples, the application of the best performing one in vitro to investigate the impact on F. graminearum growth, followed by analyzing its effect on Fusarium toxins accumulation, and Fusarium transcriptomics in the barley leaf pathosystem. Confirmatory antifungal assays revealed that CS_10, a specific batch of chitosan, retarded Fusarium growth with an application concentration of 200 ppm, significantly reducing toxin synthesis and disease symptoms in Fusarium-inoculated barley leaves. RNA-Seq analysis of F. graminearum in barley leaf pathosystem exposed to CS_10 showed a list of differentially expressed genes involved in redox balance, cell respiration, nutrient transport, cell wall degradation enzymes, ergosterol biosynthesis, and trichothecenes production. The genes functioning in these essential pathways are discussed and assigned as critical checkpoints to control Fusarium infections. The results suggest some important molecular targets in F. graminearum that may be suitable in gene-specific targeting or transgene-free methods, such as spray-induced gene silencing during host-pathogen interactions.

Biocontrol Efficacy of Endophyte Pseudomonas poae to Alleviate Fusarium Seedling Blight by Refining the Morpho-Physiological Attributes of Wheat

Some endophyte bacteria can improve plant growth and suppress plant diseases. However, little is known about the potential of endophytes bacteria to promote wheat growth and suppress the Fusarium seedling blight pathogen Fusarium graminearum. This study was conducted to isolate and identify endophytic bacteria and evaluate their efficacy for the plant growth promotion and disease suppression of Fusarium seedling blight (FSB) in wheat. The Pseudomonas poae strain CO showed strong antifungal activity in vitro and under greenhouse conditions against F. graminearum strain PH-1. The cell-free supernatants (CFSs) of P. poae strain CO were able to inhibit the mycelium growth, the number of colonies forming, spore germination, germ tube length, and the mycotoxin production of FSB with an inhibition rate of 87.00, 62.25, 51.33, 69.29, and 71.08%, respectively, with the highest concentration of CFSs. The results indicated that P. poae exhibited multifarious antifungal properties, such as the production of hydrolytic enzymes, siderophores, and lipopeptides. In addition, compared to untreated seeds, wheat plants treated with the strain showed significant growth rates, where root and shoot length increased by about 33% and the weight of fresh roots, fresh shoots, dry roots, and dry shoots by 50%. In addition, the strain produced high levels of indole-3-acetic acid, phosphate solubilization, and nitrogen fixation. Finally, the strain demonstrated strong antagonistic properties as well as a variety of plant growth-promoting properties. Thus, this result suggest that this strain could be used as an alternate to synthetic chemicals, which can serve as an effective method of protecting wheat from fungal infection.

Replacement of polyethylene oxide by peach gum to produce an active film using Litsea cubeba essential oil and its application in beef

This study evaluated the effects of adding various concentrations (0 %, 1 %, 2 %, and 3 %) of peach gum (PG) to films made from polyethylene oxide (PEO) combined with Litsea cubeba essential oil (LCEO) to be utilized as active packaging for food in the future. The findings showed that the film containing PG 2 % concentration had the best physic-mechanical properties. In films made with PG, the glass transition temperature was significantly improved. Combining PG and PEO resulted in films that were brighter in color, had lower WVP values, and had the lowest water activity. Furthermore, XRD demonstrated that PG additions were compatible with the film of PEO blended with LCEO. The PG films formulated with PG presented high antioxidant and antibacterial activity against Staphylococcus aureus and E. coli. Wrapping beef with P2G2 film led to maintaining its quality with suitable levels of pH, TBARS, and TVB-N. This also decreased the number of E. coli and S. aureus in beef throughout the storage period. The results indicate that adding PG to PEO films enhances their suitability for food preservation.

Enhancement Effect of Chitosan Coating on Inhibition of Deoxynivalenol Accumulation by Litsea cubeba Essential Oil Emulsion during Malting

The purpose of this work was to study the enhancement effect of chitosan coating on inhibition of deoxynivalenol (DON) accumulation by Litsea cubeba essential oil emulsion during malting. Firstly, the primary emulsion suitable for malting process was screened and the improvement effect of chitosan coating on the properties of primary emulsion was studied. On this basis, chitosan-based Litsea cubeba essential oil emulsion was applied to malting processing. The results showed that the primary emulsion of Litsea cubeba essential oil had good antifungal properties and a minimal effect on the germinability of barley compared with other primary emulsions. The addition of chitosan can improve the physical stability and antifungal ability of the emulsion and reduce the effect of the emulsion on barley germination. When 100 g of chitosan-based Litsea cubeba essential oil emulsion (40 mg/g) was applied to the malting process, the germination rate of barley was 87.7% and the DON concentration of finished malt was reduced to 690 μg/kg, which was 20.9% lower than that of the control. Meanwhile, the other indexes of malt produced by secondary emulsion treatment (after adding chitosan) increased significantly compared with those of malt produced by primary emulsion. This study was of great significance for the application of emulsion to inhibit the accumulation of mycotoxin during malting.

Green-Synthesization of Silver Nanoparticles Using Endophytic Bacteria Isolated from Garlic and Its Antifungal Activity against Wheat Fusarium Head Blight Pathogen Fusarium Graminearum

Nanoparticles are expected to play a vital role in the management of future plant diseases, and they are expected to provide an environmentally friendly alternative to traditional synthetic fungicides. In the present study, silver nanoparticles (AgNPs) were green synthesized through the mediation by using the endophytic bacterium Pseudomonas poae strain CO, which was isolated from garlic plants (Allium sativum). Following a confirmation analysis that used UV-Vis, we examined the in vitro antifungal activity of the biosynthesized AgNPs with the size of 19.8-44.9 nm, which showed strong inhibition in the mycelium growth, spore germination, the length of the germ tubes, and the mycotoxin production of the wheat Fusarium head blight pathogen Fusarium graminearum. Furthermore, the microscopic examination showed that the morphological of mycelia had deformities and collapsed when treated with AgNPs, causing DNA and proteins to leak outside cells. The biosynthesized AgNPs with strong antifungal activity were further characterized based on analyses of X-ray diffraction, transmission electron microscopy, scanning electron microscopy, EDS profiles, and Fourier transform infrared spectroscopy. Overall, the results from this study clearly indicate that the biosynthesized AgNPs may have a great potential in protecting wheat from fungal infection.

Influence of nonionic and ionic surfactants on the antifungal and mycotoxin inhibitory efficacy of cinnamon oil nanoemulsions

The influence of ionic surfactants (cationic surfactant lauric arginate and anionic surfactant lysolecithin) on the physical properties, antifungal and mycotoxin inhibitory efficacy of Tween 80 stabilized cinnamon oil-in-water nanoemulsions was investigated. Nanoemulsion droplets of similar particle diameter (∼100 nm), but variable electrical characteristics, were formed by mixing 0.1 wt% ionic surfactant with 0.9 wt% Tween 80 before homogenization. The nanoemulsions were physically stable over 28 days at 23 °C. The antifungal activity (against mycelial growth and spore germination) and mycotoxin inhibitory activity of cinnamon oil nanoemulsions bearing positive, neutral, and negative charge surface was then evaluated against two chemotypes of Fusarium graminearum. In general, the cinnamon oil played a decisive role in the resulting antifungal and mycotoxin inhibitory activities. The surfactant charge had a limited impact on the antifungal mycotoxin inhibitory activities of cinnamon oil in the nanoemulsions. Both ionic surfactant-based cinnamon oil nanoemulsions showed greater activity in inhibiting mycelial growth and mycotoxin production of F. graminearum than those based on Tween 80. Treatment of mycelium with cinnamon oil nanoemulsions resulted in the loss of cytoplasm from fungal hyphae, and accounted for the antifungal action. These results have important implications for the design of essential oil based nanoemulsions as effective antifungal delivery systems in foods.