Curcuma longa L. essential oil composition,antioxidant effect,and effect on Fusarium verticillioides and fumonisin production

Essential oils may be an alternative to the use of synthetic fungicides for the control of fungi involved in agricultural product deterioration. The aim of the present study was to evaluate the composition and antioxidant effect of turmeric essential oil and its antifungal and antimycotoxigenic action on Fusarium verticillioides (Sacc.) Nirenberg. The essential oil major components were α-turmerone (42.6%), β-turmerone (16.0%) and ar-turmerone (12.9%). The half-maximal inhibitory concentration (IC₅₀) for the radical scavenging capacities of 2,2′-azino-bis-3-ethylbenzothiazoline-6-sulphonic acid (ABTS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) were 0.54 and 10.03 mg/ml, respectively, indicating good antioxidant activity. The application of 17.9 and 294.9 μg/ml of turmeric essential oil decreased the development of F. verticillioides by 56.0 and 79.3%, respectively, when compared with the fungal control. The scanning electron microscopy demonstrated that the oil decreased the thickness and the length of the microconidia. Ergosterol production significantly decreased (p < 0.05) in groups treated with the essential oil relative to the control, indicating an effect of the oil on fungal biomass. The production of B₁ and B₂ fumonisins was significantly inhibited (p < 0.05) in groups treated with the essential oil. The results suggest that turmeric essential oil has antioxidant, antifungal and antimycotoxigenic activities.