Zanthoxylum molle Rehd. essential oil as a potential natural preservative in management of Aspergillus flavus

- Chemical compositions of Z. molle essential oil were examined by GC-MS.
- The effects of oil on mycelial growth, spore germination in A. flavus were assessed.
- The oil displayed notable inhibition on mycelium weight and AFB1 content.
- The possible mechanism of the oil against A. flavus was studied by TEM.
- Practical efficacy of oil has been established as preservative in fruit system.

Essential oils are attracting attention owing to their potential as natural antimicrobial agents, and therefore, they find many applications in the food and pharmaceutical industries. This investigation aimed to evaluate the antifungal activity of Zanthoxylum molle essential oil (ZMEO) against Aspergillus flavus, a food contaminant. Gas chromatography-mass spectrometry detected 51 compounds representing 95.72% of the ZMEO. 2-Undecanone (26.81%), limonene (20.12%), and terpinen-4-ol (13.09%) were the main components. The mycelial growth of A. flavus was totally inhibited at concentrations of 8 μL/mL and 1 μL/mL ZMEO in the air at contact and vapor conditions, respectively. The ZMEO also had an inhibitory effect on spore germination in A. flavus proportional to its concentration. Moreover, the ZMEO presented evident inhibition on dry mycelium weight and synthesis of aflatoxin B1 (AFB1) by A. flavus, completely restraining AFB1 production at 6 μL/mL. This study explores the possible mechanism of the ZMEO against A. flavus by transmission electron microscopy based on changes in the cell ultrastructure. Based on the promising antifungal activity of ZMEO, the effect of the oil on resistance to decay development in cherry tomatoes (Lycopersicon esculentum) was studied in vivo by exposing inoculated and control fruit groups to essential oil vapor at 0.4 μL/mL air concentration. The results showed that ZMEO can potentially be used as an antifungal agent for preservation purposes in the food and pharmaceutical industries.