Evaluation of in-vitro antifungal activity against Fusarium incarnatum of binary and ternary combinations of lemongrass, garlic and mustard oil-encapsulated lipid nanoemulsions

Summary Encapsulated lipid nanoemulsions (EO-LNs) from garlic oil, lemongrass oil and mustard oil were prepared by a combined method of homogenization and sonication with the aim to generate highly effective formulations against Fusarium incarnatum (laboratory bioassays). Their combined binary and ternary formulations (preparations by mixing an equal volume ratio of each EO-LNs) were also tested. The synergistic/additive/antagonistic antifungal effect of the EOs (under nanoform) in their combined formulations was determined using the SynergyFinder software with the Bliss independence model. Results revealed the synergistic effect of the combined binary and ternary formulations of garlic oil-encapsulated LNs (NaG), lemongrass oil-encapsulated LNs (NaL) and mustard oil-encapsulated LNs (NaM). Furthermore, the ternary combination, at the same concentration of each constituent EO, had higher antifungal activity than the binary combinations. Nonetheless, at 600 times dilution the NaLG (binary combination) inhibited 96% the mycelial growth of F. incarnatum, which was significantly higher than the efficacy of NaMLG (ternary combination) in the same dilution. This could be possibly attributed to the 1.5-time higher concentration of each constituent EO in the binary combination compared to that in the ternary formulation. In addition, NaLG, even at the high EO concentration of 0.4 g/L, did not show any phytotoxicity symptoms on lettuce plants.