Fungicidal Activity of Artemisia sieberi Essential Oil and Nanoemulsion Against Penicillium on Oranges: Phytochemical Properties

Artemisia sieberi, a native plant of Iran, is recognized for its phytochemical properties and medicinal potential. This study explored the effects of A. sieberi essential oil nanoemulsion (NE) on antioxidant and antibacterial activities against Escherichia coli (gram-negative) and Staphylococcus aureus (gram-positive). The essential oil was extracted using a Clevenger apparatus, and the NE was prepared via spontaneous emulsification with Tween 80 as the emulsifying agent. The average particle size of the NE was determined using dynamic light scattering. The essential oil concentration for tests was set at 10%. Forty-eight chemical compounds were identified in A. sieberi, with camphor (29.93%) being the most abundant. Antioxidant tests revealed the pure essential oil (IC₅₀=38.36 mg/L) had the highest activity, followed by the 15% essential oil (IC₅₀=78.95 mg/L). Antibacterial tests showed the NE inhibited S. aureus more effectively (10 mm inhibition zone), while pure essential oil had a stronger effect on E. coli (10 mm inhibition zone). In antifungal tests, the NE performed best against Penicillium digitatum with a contamination rate of 37%, and against P. italicum with a contamination rate of 16%. The 10% essential oil treatment on P. italicum had the weakest performance, with a 91.6% infection rate higher than that of the positive control (carbendazim). The 10% NE also showed better antibacterial activity than pure essential oil, while pure oil had stronger antioxidant effects. General, A. sieberi exhibited significant antioxidant and antimicrobial properties, with its NE being more effective against bacterial strains.