Myristica fragrans essential oil nanoemulsion as novel green preservative against fungal and aflatoxin contamination of food commodities with emphasis on biochemical mode of action and molecular docking of major components

The study reports the antifungal and antiaflatoxigenic mechanism of action of chitosan fabricated Myristica fragrans essential oil fragrans essential oil nanoemulsion (Nm-MFEO) against antiaflatoxigenic strain of Aspergillus flavus (AF LHP R14). Significant inhibition in ergosterol biosynthesis by Nm-MFEO indicated plasma membrane as potential target site of antifungal action. Moreover, Nm-MFEO caused dose dependent inhibition of methylglyoxal (aflatoxin inducer) biosynthesis suggesting novel antiaflatoxigenic mechanism of action. Significant impairment in enzymatic (superoxide dismutase and catalase) and non-enzymatic (oxidized and reduced glutathione and ratio of oxidized and reduced glutathione) anti-oxidative defense molecules in AF LHP R14 cells after treatment with Nm-MFEO suggested biochemical mechanism of action. Nm-MFEO exhibited promising antioxidant activity as determined through DPPH center dot and ABTS(center dot)(+) assay with IC50 value 1.20, 0.157 mu L/mL, respectively and higher phenolic content (11.87 mu g/mg gallic acid). Further, the in silico molecular docking of major components of MFEO viz. myristicin, elemicin and thujanol with aflatoxin producing regulatory genes Ver 1 and Omt A depicted important molecular site of interaction supporting the applicability of MFEO nanoemulsion as plant based green food preservative. The present study is the first report on the effect of chitosan fabricated MFEO nanoemulsion resulting in the inhibition of methylglyoxal, thereby suggesting its future exploitation for the development of aflatoxin resistant food crop varieties through green transgenics.