Elucidation of antifungal toxicity of Callistemon lanceolatus essential oil encapsulated in chitosan nanogel against Aspergillus flavus using biochemical and in-silico approaches

The antifungal and aflatoxin B₁ (AFB₁) inhibitory effect of chemically characterised Callistemon lanceolatus essential oil (CLEO), chitosan nanoparticles, and CLEO loaded chitosan nanoparticles (CLEO-ChNPs) were investigated. Scanning electron microscope observation exhibited the spherical shape of prepared CLEO-ChNPs with an average range of 20-70 nm. An in-vitro release study revealed the controlled volatilisation of CLEO from CLEO-ChNPs. The CLEO-ChNPs caused complete inhibition of growth (4.5 µl/ml) and AFB₁ (4.0 µl/ml) production by A. flavus at a low dose compared to free CLEO (5.0 µl/ml). The antifungal and AFB₁ inhibitory toxicity of CLEO-ChNPs were elucidated using biochemical (effect on ergosterol biosynthesis, membrane cations, mitochondrial membrane potential, C-sources utilisation and cellular methylglyoxal level) and in-silico (interaction with the gene product Erg 28, Cytochrome c oxidase subunit Va, Omt-A, Ver-1, and Nor-1) approaches.

Keywords: Aflatoxin B1; essential oil; in-silico; mode of action; nanoparticles.