Inhibitory Effect of Flower-Shaped Zinc Oxide Nanostructures on the Growth and Aflatoxin Production of a Highly Toxigenic Strain of Aspergillus flavus Link

Abstract

Flower-shaped zinc oxide (ZnO) nanostructures were prepared via a simple aqueous precipitation strategy at room temperature. The as-grown nanostructures were characterized by UV–vis spectroscopy, UV–vis diffuse reflectance spectroscopy (DRS), spectrofluorometry, Fourier transform infrared (FTIR) spectroscopy with attenuated total reflection (ATR), X-ray diffraction (XRD), and field emission scanning electron microscopy (FESEM). The antifungal and anti-aflatoxigenic activities of the ZnO nanostructures were further investigated using a highly toxigenic strain of Aspergillus flavus Link under in vitro and in situ conditions. The results showed that the A. flavus isolate was inhibited to various extents by different concentrations of ZnO nanostructures, but the best inhibitions occurred at 1.25, 2.5, and 5 mM in the culture media. At these concentrations, suppression of aflatoxin biosynthesis (99.7%) was also observed. Moreover, a reasonable reduction in the aflatoxin content (69%) was observed in maize grains treated with the lowest ZnO concentration that exhibited the strongest inhibitory activity in the liquid media. SEM micrographs clearly indicate multiple degenerative alterations in fungal morphology after treatment with ZnO such as damage of the tubular filaments, loss of hyphae shape, as well as hyphae rupture. These results suggest that flower-shaped ZnO nanostructures exhibit strong antifungal and anti-aflatoxigenic activity with potential applications in the agro-food system.

Differential Antimycotic and Antioxidant Potentials of Chemically Synthesized Zinc-Based Nanoparticles Derived from Different Reducing/Complexing Agents against Pathogenic Fungi of Maize Crop

“…However, the XRD spectra for NaOH and thiourea reducing agents exhibited the presence of only hexagonal zincite phase crystals. Similar diffraction peaks have been reported for ZnNPs obtained by green synthesis from fruit parts of Citrullus colosynthis [ 14 ] and cotton linter pulp [ 11 ]. The XRD spectra of the albumin (CA) ZnNMs showed a very broad peak spanning over 30 to 50 20° diffraction region with several substantially indistinct peaks within this range indicating the occurrence of mixed crystal phase.…”

“…The size of ZnNPs and their crystal chemistry can affect the fungicidal potential as these characteristics alter the ability to trespass the fungal cell wall and membrane structures to elicit ROS response besides varying the dissolution of the ZnNPs within the fungal cell cytoplasm. The anti-fungal activity of ZnNPs have been identified against Alternaria alternata [ 13 ], Aspergillus flavus [ 14 ], Botrytis cinerea [ 11 , 15 ], Candida albicans [ 16 ], Fusarium graminearum [ 17 ], Fusarium moniliforme [ 8 ], Fusarium solani [ 18 ], Penicillium sp. [ 19 , 20 , 21 ], Penicillium expansum [ 22 ], Pythium ultimum and P. aphanidermatum [ 23 ], Rhizopus stolonifera [ 24 ] and many more fungal pathogens of plants.…”

Biofabrication of Zinc Oxide Nanoparticles With Syzygium aromaticum Flower Buds Extract and Finding Its Novel Application in Controlling the Growth and Mycotoxins of Fusarium graminearum

“…Best of our knowledge, until the date, no report is available on antifungal and antimycotoxin abilities of biofabricated ZnO NPs on F. graminearum and present study is first report. Most recently, Hernández-Meléndez et al (2018) reported that flower-shaped ZnO inhibit the growth and aflatoxin production of A. flavus by multiple degenerative alterations in fungi via ROS generation. Besides, Savi et al (2013) proved that zinc compounds could generate intracellular ROS and exhibit strong inhibitory activity on growth and fumonisin mycotoxin production of F. verticillioides by detrimental action on hyphae and conidia.…”

Assessing the Aflatoxin B1 Adsorption Capacity between Biosorbents Using an In Vitro Multicompartmental Model Simulating the Dynamic Conditions in the Gastrointestinal Tract of Poultry

“…The biosorbents were studied by X-ray diffractometry according to the recommendations of Hernández-Meléndez et al [ 43 ]. The XRD patterns were collected in the region of 2θ from 10° to 80° using a 0.02° step size.…”