Frontiers in Microbiology (Aug 2022)
Chitosan encompassed Aniba rosaeodora essential oil as innovative green candidate for antifungal and antiaflatoxigenic activity in millets with emphasis on cellular and its mode of action
Abstract
The present study demonstrates first time investigation on encapsulation of Aniba rosaeodora essential oil into chitosan nanoemulsion (AREO-CsNe) with the aim of improvement of its antifungal, and aflatoxin B1 (AFB1) inhibitory performance in real food system. The GC–MS analysis of AREO revealed the presence of linalool (81.46%) as a major component. The successful encapsulation of EO into CsNe was confirmed through SEM, FTIR, and XRD analysis. The in-vitro release study showed the controlled release of AREO. AREO-CsNe caused complete inhibition of Aspergillus flavus (AFLHPSi-1) growth and AFB1 production at 0.8 and 0.6 μl/ml, respectively, which was far better than AREO (1.4 and 1.2 μl/ml, respectively). Impairment of ergosterol biosynthesis coupled with enhancement of cellular materials leakage confirmed plasma membrane as the possible antifungal target of both AREO and AREO-CsNe. Significant inhibition of methylglyoxal (AFB1 inducer) synthesis in AFLHPSi-1 cells by AREO and AREO-CsNe confirmed their novel antiaflatoxigenic mode of action. In-silico molecular docking studies revealed effective interaction of linalool with Ver-1 and Omt-A proteins, leading to inhibition of AFB1 biosynthesis. Further, AREO-CsNe showed enhanced antioxidant activity with IC50 values 3.792 and 1.706 μl/ml against DPPH• and ABTS•+ radicals, respectively. In addition, AREO-CsNe caused 100% protection of stored millets (Setaria italica seeds) from AFB1 contamination and lipid peroxidation over a period of 1 year without compromising its sensory properties and exhibited high safety profile with LD50 value 9538.742 μl/kg body weight. Based on enhanced performance of AREO-CsNe over AREO, it can be recommended as a novel substitute of synthetic preservative for preservation of stored millets.
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