Cellular, physiological and molecular approaches to investigate the antifungal and anti-aflatoxigenic effects of thyme essential oil on Aspergillus flavus

Food Chem. 2020 Jun 15:315:126096. doi: 10.1016/j.foodchem.2019.126096. Epub 2019 Dec 27.

Abstract

Several approaches, including the detection of apoptotic-like cell death, aflatoxin B1 (AFB1) production and gene expression analysis, were carried out to provide insights into the antifungal and anti-aflatoxigenic effects of thyme essential oil (EO) on Aspergillus flavus. At 0.5 µL mL-1, thyme EO completely inhibited A. flavus growth. Furthermore, this antifungal activity triggered significant apoptosis, via nuclear condensation (87.5% of nuclei analyzed) and plasma membrane damage (in 100% of treated hyphae). Further analysis of AFB1 production and gene expression related to secondary metabolism (laeA) and the mechanism of virulence (lipA and meT) of A. flavus in the presence of thyme EO indicated important physiological changes related to its anti-aflatoxigenic property. These results highlight the potent antifungal abilities of thyme EO in controlling A. flavus and AFB1 production, especially the abilities that operate by exerting changes at the molecular level and inducing significant apoptotic-like cell death.

Keywords: Aflatoxins; Apoptosis; Essential oil; Gene expression; Mycotoxins.

MeSH terms

  • Aflatoxin B1 / genetics
  • Aflatoxin B1 / metabolism
  • Antifungal Agents / chemistry
  • Antifungal Agents / pharmacology*
  • Aspergillus flavus / drug effects*
  • Aspergillus flavus / physiology*
  • Gene Expression Regulation, Fungal / drug effects
  • Oils, Volatile / chemistry
  • Oils, Volatile / pharmacology*
  • Secondary Metabolism / genetics
  • Thymus Plant / chemistry*

Substances

  • Antifungal Agents
  • Oils, Volatile
  • Aflatoxin B1