The aim of this study was to investigate the effect of cinnamon and ginger oils on some biological, physical and physico-chemical properties of chitosan-carboxymethyl cellulose films emulsified with ...oleic acid. Films containing cinnamon oil showed higher antifungal activity in vitro against Aspergillus niger than those containing ginger. Unlike ginger-based materials, the film crystallinity decreased with an increasing concentration of cinnamon oil. The microstructure of the active films was evaluated by scanning electron microscopy and results showed a distinct morphology depending on the composition of essential oils (EOs). As expected, both EOs decreased water vapor permeability of the active films, with a higher decreasing effect for cinnamon. Resulting water contact angles were improved by 36–59% for ginger films and 65–93% for cinnamon films, depending on the EO concentration. Regarding mechanical properties, highest concentrations of EOs led to an improvement of 328% and 111% of the elongation with cinnamon and ginger, respectively. The different behavior of both EOs regarding physical, mechanical, thermal and water vapor permeability properties could be attributed to differences in their chemical compositions. The presence of cinnamaldehyde, in cinnamon essential oil, can create many kinds of interactions with the network made by carboxymethyl cellulose, chitosan and oleic acid. Findings in this work suggest that EOs and especially cinnamon oil could be used to plasticize chitosan-carboxymethyl cellulose films while improving moisture permeability and maintaining antifungal activity. This bio-based material could be of interest for food preservation.
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•Chitosan and carboxymethyl cellulose were successfully associated to create a film.•Cinnamon oil strongly plasticized chitosan - carboxymethyl cellulose films.•Cinnamon oil showed higher antifungal activity in vitro against Aspergillus niger than ginger oil.•Differences in film properties were likely due to cinnamaldehyde in cinnamon essential oil.
Chitosan edible films and coatings have shown great promise for their application in food preservation and also are promising systems to be used as essential oil (EO) carriers. This review reports ...the most recent and relevant studies concerning chitosan films and coatings containing EOs. The effect of EO incorporation on the antioxidant, antibacterial and antifungal activities of chitosan films and coatings in vitro and in vivo, as well as their applications in food systems have been discussed. In general, incorporation of EOs significantly increased the antioxidant, antibacterial and antifungal efficacy of chitosan films and coatings in vitro. EO-incorporated films and coatings also showed greater effectiveness against postharvest fungi and foodborne bacteria in food systems than pure films and coatings. The application of chitosan films and coatings containing EOs usually led to an extension of the shelf-life and reduction of lipid peroxidation of fish and meat products over pure chitosan films and coatings. In addition, chitosan coatings incorporated with EOs were more effective in maintaining fruit and vegetable quality, and controlling their postharvest decay during storage and shelf life than pure chitosan coatings.
•Incorporation of EOs increased antioxidant and antimicrobial efficacy of chitosan films and coating.•Chitosan-EOs were more effective in extension of shelf-life and maintaining quality than chitosan.•Chitosan-EOs were more effective against pathogen and fungi in food than chitosan.
Nano-fungicides are expected to play an important role in future plant disease management as eco-friendly alternatives of conventional synthetic fungicides. In the present study, the sensitivity of ...seven fungal species, known to cause foliar and soil-borne diseases, to nanoparticles (NPs) containing copper (Cu-NPs, CuO-NPs), silver (Ag-NPs) and zinc (ZnO-NPs) was assessed in vitro. Mycelial growth assays revealed that Cu-NPs with mean inhibition rates, EC50, ranging between 162 and 310 μg/mL were most effective among the NPs tested in inhibiting fungal growth, followed by ZnO-NPs with EC50 ranging between 235 and 848 μg/mL. All fungal species were practically insensitive to CuO-NPs and Ag-NPs except for B. cinerea, which was equally sensitive to Ag-NPs and Cu-NPs (EC50 = 307 μg/mL). Cu-NPs were more fungitoxic in terms of mycelial growth, to almost all species tested, than a protective fungicide containing Cu(OH)2, which was used as a reference. Fungitoxicity experiments with the NPs tested and bulk size reagents containing the respective metals revealed that ZnO-NPs were more toxic to all fungal species tested than ZnSO4, whereas Cu-NPs were more fungitoxic than CuSO4 in all cases, except for B. cinerea, A. alternata and M. fructicola. The existence of a positive correlation between Cu-NPs and CuO-NPs toxicity and, at the same time, the absence of any correlation between NPs tested and their respective bulk metal counterparts indicated potential differences in the mode of action between bulk and nanosized antifungal ingredients. Although there was considerable variation between fungal species, all NPs were generally 10 to 100 fold more fungitoxic to spores than hyphae and in the majority of cases more effective than Cu(OH)2, as revealed by colony formation bioassays. NPs significantly suppressed grey mold symptoms on plum fruit, especially Ag-NPs, which completely inhibited disease development. Consequently, tested NPs have the potential to be used as protective antifungal agents.
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•NPs are effective against both mycelial growth and spore germination.•Mode of fungitoxic action of Cu-NPs is apparently different than that of their bulk counterparts.•Ag-NPs and Cu-NPs significantly suppressed B. cinerea symptoms in vivo.•NPs tested exhibit promising potentials as nano-fungicides.
Biological reduction agents are being explored worldwide to minimize the effects of toxic chemicals used in nanoparticle fabrication. The present study states a green approach for the synthesis of ...zinc oxide nanoparticles employing aqueous flower extract of Nyctanthes arbor-tristis. Flower extract was used as the biological reduction agent for synthesizing zinc oxide nanoparticles from zinc acetate dihydrate. Synthesis conditions were optimized for maximal and narrow size range synthesis of zinc oxide nanoparticles. The resultant nanopowder was characterized using various analytical techniques, such as UV–Visible spectroscopy, Fourier Transform Infrared spectroscopy, X-ray diffraction, Dynamic Light Scattering and Transmission Electron Microscopy. The nanopowder was stored in dried form and was found to be stable after 4months. The size range of nanoparticles obtained upon synthesis at optimum conditions was 12–32nm as reported by TEM. X-ray diffraction studies confirmed the crystalline nature of the nanoparticles indicating particle size within the range provided by electron microscopy data. Nanoparticles were tested for their antifungal potential and were found to be active against all five tested phytopathogens with lowest MIC value recorded as 16μg/mL. Hence, an easy and effective green approach for synthesis of zinc oxide nanoparticles, with efficient antifungal potential is reported in this study.
Iron oxide nanoparticles with particle size 10–30 nm were prepared by a green approach using tannic acid as reducing and capping agent. These nanoparticles were characterized by X-ray diffractometry ...(XRD), high resolution field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). The prepared iron oxide nanoparticles were also evaluated for their antifungal activity against Trichothecium roseum, Cladosporium herbarum, Penicillium chrysogenum, Alternaria alternata and Aspergillus niger. The antifungal activity was observed as inhibition in spore germination and by determining the zone of inhibition of fungal pathogens caused by different concentrations of iron oxide nanoparticles on culture media. It was observed from the present study that Fe2O3 nanoparticles showed significant antimycotic activity against all the tested fungal pathogens. Highest inhibition in spore germination was caused against T. roseum (87.74%) followed by C. herbarum (84.89%). The highest zone of inhibition by iron oxide nanoparticles was reported against P. chrysogenum (28.67 mm) followed by A. niger (26.33 mm), T. roseum (22.67 mm), A. alternata (21.33 mm) and least against C. herbarum (18.00 mm). Activity index was recorded highest against P. chrysogenum (0.81). The MIC value of Fe2O3 NP varies between 0.063 and 0.016 mg/ml for different fungal pathogens that is comparable with the MIC value shown by the standard, revealing the efficacy of iron oxide NP's against different fungal pathogens.
•Iron oxide nanoparticles were prepared by a green approach using tannic acid in alkaline medium.•Iron oxide NP's fabricated were crystalline, free from impurities, stable, and possess promising antifungal activities.•The prepared iron oxide NP's were found most effective against Penicillium chrysogenum and Aspergillus niger.
Objective: In order to prevent and control the infection of Candida albicans, the antifungal activity, possible mechanism of myriocin against C. albicans and its biofilm were studied. Methods: The ...antifungal activity of myriocin was investigated by microdilution method. The effect of myriocin on fungal cell wall or membrane was evaluated by adding sorbitol, ergosterol or phytosphingosine (PHS). The damage to the cell membrane was investigated with propidium iodide (PI) staining and visualized by Scanning electron microscope (SEM). The effects on biofilms and extracellular polysaccharides (EPS) were observed by crystal violet staining method and phenol-sulfuric acid method respectively. The adhesion of C. albicans cells to hydrocarbons was tested to evaluate cell surface hydrophobic (CSH). The combined effects of myriocin and antifungal drugs commonly used in clinical practice were investigated by using the checkerboard microdilution method. Results: MICs were found to be 0.125~4 µg/ml. Myriocin was found to affect both cell wall and cell membrane. After exposure to myriocin, biofilm and EPS were found to be inhibited and removed, and the CSH was decreased. The combined fungistasis of myriocin and voriconazole (VCZ) or amphotericin B (AMB) were additive. Conclusion: Myriocin had significant antifungal activity against C. albicans, and the antifungal mechanisms might be cell wall and membrane damage. Myriocin effectively inhibited and eliminated biofilms, and its mechanism may be related to the inhibition of EPS and CSH.
Citrus fruits, widely consumed around the world, can be negatively affected by pests and fungal infections during their cultivation, handling, transportation, and storage, thus resulting in ...substantial yield losses and food waste. The use of natural preservatives like chitosan (CHT) and essential oils (EOs) is a promising approach for reducing chemical inputs to preserve food products.
This study investigated the effects of CHT, extracted from crab shells and the fungus Pleorotus ostreatus, alone and in combination with mandarin (Citrus × reticulata Blanco, Rutaceae) essential oil (MEO), as an oviposition deterrent towards Ceratitis capitata (Diptera: Tephritidae), the Mediterranean fruit fly, and growth inhibitor of Penicillium (P. expansum, P. digitatum, and P. italicum) spp. fungi, the causal agents of apple and citrus rot.
A solution of 1.0% CHT of both origins (from crab shells and P. ostreatus) added with MEO resulted as the best combination to significantly reduce the oviposition percentage of C. capitata as well as mycelial growth and spore germination of Penicillium isolates and their pathogenic activity on Citrus japonica Thunb. (kumquats) fruits.
According to results here collected, CHT added with MEO represents a valid combination to be used as an edible film and coating as part of an integrated control strategy to improve the shelf-life of fresh citrus fruits. Furthermore, fungal CHT, here used for the first time in combination with MEO, can be an excellent alternative to reply to the eating habits and necessities of the final consumers.
•Chitosan (CHT) of different origins was combined with mandarin essential oil (MEO).•We used CHT solutions from crab shells and the fungus Pleurotus ostreatus.•CHT + MEO inhibited mycelium and spore germination of Penicillium spp.•CHT + MEO protected kumquat fruit against the oviposition by Ceratitis capitata.•CHT of both origins + MEO could be valid tools in kumquats' post-harvest protection.
Endophytes colonize the interior of plant tissues without causing any damage to their hosts. The plant Sapindus saponaria L., popularly known as ‘sabão-de-soldado’, presents a diversified endophytic ...microbiota and also medicinal properties. Endophytic microorganisms may produce secondary metabolites with different biotechnological properties. The present study aimed to evaluate the in vitro antibacterial and antifungal capacity of the crude extract of secondary metabolites produced by the endophytic bacteria P. aeruginosa SS93 isolated from S. saponaria leaves. The metabolites extract was obtained using the organic solvent ethyl acetate, and the antimicrobial activities were tested against six pathogenic bacteria (Enterococcus faecalis ATCC 29212, Pseudomonas aeruginosa ATCC 27853, Shigella flexneri ATCC 12022, Salmonella enterica CCCD a016, Escherichia coli ATCC 25922, and Staphylococcus aureus ATCC 25923), and pathogenic fungi (Fusarium oxysporum, Glomerella sp., Sphaceloma sp., Fusarium solani, Maniliophtora perniciosa, and Sclerotinia sclerotiorum), by agar diffusion method. In the antibacterial assay, the best results were obtained against E. faecalis and S. aureus, where the formation of inhibition halos was observed in all tested concentrations, especially at 500 and 700 µg mL-1. Positive inhibitory activity against phytopathogenic fungi was observed, with the highest inhibition recorded against F. oxysporum (61.1%), followed by Sphaceloma sp. (55.7%), M. perniciosa (35.6%), F. solani (34.4%), and Glomerella sp. (30.4%).
Gray mold disease, caused by Botrytis cinerea is a major postharvest disease impacting fruits such as strawberries and tomatoes. This study explores the use of volatile organic compounds (VOCs) ...produced by Bacillus spp. as eco-friendly biocontrol agents against B. cinerea. In vitro experiments demonstrated that VOCs from Bacillus sp. LNXM12, B. thuringiensis GBAC46, and B. zhanghouensis LLTC93-VOCs inhibited fungal growth by 61.2%, 40.5%, and 21.6%, respectively, compared to the control. LNXM12 was selected for further experiments due to its highest control efficacy of 58.3% and 76.6% on tomato and strawberry fruits, respectively. The LNXM12 VOCs were identified through gas chromatography–mass spectrometry (GC–MS) analysis, and 22 VOCs were identified. Synthetic VOCs with the highest probability percentage, namely ethyloctynol, 3-methyl-2-pentanone (3M2P), 1,3-butadiene-N, N-dimethylformamide (DMF), and squalene were used in experiments. The results showed that the synthetic VOCs ethyloctynol and 3M2P were highly effective, with an inhibition rate of 56.8 and 57.1% against fungal mycelium radial growth at 120 μg/mL on agar plates. Trypan blue staining revealed strongly disrupted, deeper blue, and lysed mycelium in VOC-treated B. cinerea. The scanning and transmission electron microscope (SEM and TEM) results showed that fungal mycelium was smaller, irregular, and shrunken after synthetic VOC treatments. Furthermore, the synthetic VOCs Ethyloctynol and 3M2P revealed high control efficacy on tomatoes and strawberries infected by B. cinerea. The control efficacy on leaves was 67.2%, 66.1% and 64.5%, 78.4% respectively. Similarly, the control efficiency on fruits was 45.5%, 67.3% and 46.3% 65.1%. The expression of virulence genes in B. cinerea was analyzed, and the results revealed that selected genes BcSpl1, BcXyn11A, BcPG2, BcNoxB, BcNoxR, and BcPG1 were downregulated after VOCs treatment. The overall result revealed novel mechanisms by which Bacillus sp. volatiles control postharvest gray mold disease.
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•The volatile organic compounds of Bacillus sp. LNXM12 possesses antifungal activity.•The synthetic VOCs showed strong biocontrol efficacy against B. cinerea.•VOCs suppressed B. cinerea metabolic activity, leading to ultrastructural changes in the fungal mycelium.•LNXM12-VOCs downregulated the expression of virulence-related genes.•LNXM12-VOCs controlled the gray mold disease on tomatoes and strawberries.
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