Phytochemical investigation of cumin, black cumin, and lavender essential oils and their effects against tomato pathogenic fungus (Fusarium oxysporum)

The current study aimed to investigate the antifungal activities of cumin, black cumin, and lavender essential oils and their maltodextrin-based coatings against Fusarium oxysporum, one of the most locally predominant tomato fungal pathogens (Tehran, Iran). Also, investigation of some qualitative characteristics of coated tomato fruits during storage was aimed. The phytochemical constituents of the essential oils were evaluated using GC and GC–MS methods. Also, the inhibitory activities of the oils were examined against spore germination, mycelial growth, and fungal infection development on tomato fruits. According to the results, cuminaldehyde (34.54 %), γ-terpinene (18.30 %), p-cymen-7-ol (13.19 %) and p-cymenene (12.82 %) in cumin, carvone (28.74 %), p-cymen-7-ol (12.02 %), p-cymenene (11.55 %), safrole (8.93 %) and β-pinene (5.88 %) in black cumin, and camphor (19.11 %), eucalyptol (15.90 %), α-pinene (6.69 %), 3-carene (6.50 %) and β-Caryophyllene (5.38 %) in lavender essential oil were determined as main components. In spore germination assay, cumin, black cumin, and lavender essential oils exhibited potent activities with IC50 values of 1.05, 0.64 and 0.89 mg/mL, respectively. While, kresoxim-methyl (a standard antifungal agent) inhibited the fungal strain with IC50 value of 0.11 mg/mL. Furthermore, black cumin oil showed the most activities against mycelial growth of fungus. Furthermore, the coating enriched with black cumin oil showed the most inhibitory activity to reduce fungal growth on inoculated fruits, with a severity reduction of 79.2%. Whereas, cumin and lavender coatings showed significant activities with 71.43 and 38.09% inhibition, respectively. The results indicated that black cumin coating is a potent antifungal coating that of interest for the bioactive packaging of tomato fruits to extend their shelf life.