Illicium verum essential oil, a potential natural fumigant in preservation of lotus seeds from fungal contamination.

The antifungal properties of Illicium verum essential oil (IV-EO) against a toxigenic strain of Aspergillus flavus (A. flavus) were analyzed in order to determine its use in the preservation of lotus seeds. GC/MS analysis of IV-EO revealed that its main components are trans-anethole (91.32%), D-Limonene (2.0%) and estragole (2.0%). The antifungal activity of IV-EO against A. flavus infection was analyzed in vitro upon A. flavus with the minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) determined to be 2.0 and 4.0 μL/mL, respectively. IV-EO exhibited strong inhibitory effects on the mycelial growth and spore production of A. flavus, and caused a significant reduction in dry mycelium weight and aflatoxin B1 and B2 (AFB1 and AFB2) biosynthesis. Complete inhibition was observed at an IV-EO concentration of 3.6 μL/mL. Analysis in an in vivo (food system) demonstrated that IV-EO inhibited AFB1 and AFB2 accumulation in lotus seeds to varying degrees depending on its concentration, and completely inhibited aflatoxin production at concentrations above 6.0 μL/g. Morphological studies carried out using SEM revealed that ultra-structural changes in the hyphae and conidiophore structures following IV-EO treatment. Therefore, IV-EO has demonstrated its practical efficacy as a new biological fumigant in the preservation of lotus seeds.