Nanohexaconazole: synthesis, characterisation and efficacy of a novel fungicidal nanodispersion

Abstract

Here, the authors describe a simple method to formulate the nanodispersion of hexaconazole (hexa); henceforth, referred to as nanohexaconazole (N-hexa) that is water soluble and effective against several species of Aspergillus. Size and shape of the prepared nanocomposite was determined with high-resolution transmission electron microscopy and field-emission scanning electron microscopy. Nanohexaconazole structure was further confirmed by Fourier-transform infrared spectroscopy and gas chromatography-mass spectrometry. The antifungal efficacy of nanohexaconazole (N-hexa) was studied in vitro, compared with micronised hexaconazole (M-hexa) at different doses (5 ppm, 10 ppm and control) against two food pathogenic fungi: Aspergillus niger (MTCC 282, MTCC 2196 and BDS 113) and Aspergillus fumigatus through poisoned food technique. A dose-dependent significant growth inhibition was observed in nanohexaconazole (N-hexa) treated fungal sample compared with that of micronised hexaconazole (M-hexa). Micrographic studies for the morphological analysis of control and nanohexaconazole (N-hexa) treated fungal samples were done, exhibited an alternation in fungal morphology. Results showed that nanohexaconazole (N-hexa) is more efficacious than commercially available micronised hexaconazole (M-hexa). In future nanohexaconazole (N-hexa) could be a possible candidate for modern medical science and also reduce damage to the environment from injudicious use of pesticides.

Fig. 1

Synthesis and characterisation of N‐hexa (a) HR‐TEM image of N‐hexa, (b) Close view HR‐TEM image of N‐hexa, (c) Typical of FE‐SEM image of the PEG encapsulated N‐hexa, (d) FTIR analysis of N‐hexa

Fig. 2

Further characterisation was done by GC–MS of N‐hexa

Fig. 3

Comparative antifungal effect of N‐hexa and M‐hexa against the different fungal sample (a) A. fumigates, (b) A. niger (MTCC 282) after 72 h of incubation, (c) Reduction in radial growth of N‐hexa and M‐hexa‐treated fungi A. niger [BDS 113, MTCC 282, MTCC 2196] and A. fumigatus after 48, (d) 72 h incubation (mean of zone diameter ± standard error)

Fig. 4

FE‐SEM image of the treated fungal sample (a) Control conidia, (b) M‐hexa‐treated fungal sample showing malformed conidia, (c) N‐hexa showing additional damage to the membrane of the treated fungal sample. Arrows demonstrated the membrane damage