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

ABSTRACT

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.

Graphical Abstract

KEYWORDS:

• Aflatoxin B₁
• essential oil
• mode of action
• nanoparticles
• in-silico

Acknowledgments

The author gratefully acknowledges the Science and Engineering Research Board (Scheme No. ECR/2016/000299) New Delhi, India for the financial support. Akshay Kumar is thankful to the Council of Scientific and Industrial Research (CSIR), New Delhi, India for financial support as a junior research fellowship (09/013(0747)/2018-EMR-1). We are thankful to the Head, CAS in Botany, Banaras Hindu University, Varanasi for Instrumental facilities. We are also thankful to Indian Institute of Technology, Banaras Hindu 545 University, Varanasi for SEM.

Disclosure statement

The authors declare that there are no conflicts of interest.

Additional information

Funding

This work was supported by the Science and Engineering Research Board (Scheme No. ECR/2016/000299) New Delhi, India .