Chemical composition and antibacterial activity of essential oils of Cinnamomum cassia and Syzygium aromaticum plants and their nanoparticles against Erwinia amylovora

This study aimed at evaluating the antibacterial activity of Cinnamomum cassia and Syzygium aromaticum essential oils and their nanoparticles (EOs-NPS) against Erwinia amylovora, the causal agent of fire blight disease. First, EOs of C. cassia and S. aromaticum were obtained by hydrodistillation and analysed using a GC–MS/FID. Results showed that the main components of C. cassia EOs are E-Cinnamaldehyde (73.23%), alpha-Copaene (6.44%), and Eugenol (4.23%) while the EOs of S. aromaticum showed the presence of Eugenol (58.64%), β-Caryophyllene (32.91%), and Humulene (3.25%). C. cassia EOs was the most effective with an inhibition zone of 37.7 mm and a minimum bactericidal concentration (MBC) of 1.04%. However, EOs-NPS of C. cassia had greater effects than S. aromaticum with an MBC of 0.75%, rather than the effect of EOs alone. Significant reduction of the disease incidence (86%) was observed in the in vivo pre-treatment using EOs-NPS of C. cassia. Therefore, C. cassia EOs-NPS is recommended against E. amylovora.