ABSTRACT
The Eucalyptus genus, characterized by its imposing stature and fragrant foliage, has been a source of fascination for humanity over the centuries. The focus of the present investigation was directed towards the essentials oils (EOs) of five Eucalyptus trees cultivated in Tunisia. The GC-MS analysis unveiled unique compositional profiles, a finding substantiated by both Hierarchical Clustering Analysis (HCA) and Principal Component Analysis (PCA) conducted on the leaves EOs. These analyses resulted in the formation of discrete HCA clades, delineating 23 significant components. Notably, the percentage of eucalyptol emerged as the pivotal factor demarcating the separation between three distinct groups. The statistical analysis revealed a dose-dependent relationship in both phytotoxicity evaluation and antibacterial activity. The EOs from Eucalyptus loxophleba and E. salubris exhibited the highest phytotoxicity, inhibiting radical elongation and germination of various seeds, especially Sinapis arvensis and Raphanus sativus. The antimicrobial assessment demonstrated significant inhibitory effects of the EOs on bacterial strains, with MIC values spanning from 14 to exceeding 50 mg/ml. The EOs also affected biofilm formation and cellular metabolism, displaying varied efficacy among different Eucalyptus species against some bacterial strains. The EOs exhibited selective inhibition against acetylcholinesterase (AChE), butyrylcholinesterase (BChE), α-amylase, and α-glucosidase. E. campaspe EO showed the highest AChE activity, while E. loxophleba and E. salubris EOs were most potent toward α-amylase. E. loxophleba EO demonstrated notable activity against α-glucosidase. Overall, these findings provide important data about the diverse biological activities of Eucalyptus EOs, suggesting potential applications in agriculture, medicine, and pharmacy.
ABSTRACT
Forest species are characterized by their wealth of essential oils (EOs), which play key requested for alternative control methods against weeds, fungi and pests. This study reports the chemical composition and highlight the antioxidant, antifungal and phytotoxic properties of the EOs obtained from Eucalyptus populifolia Desf, Eucalyptus woollsiana and Eucalyptus exserta. The EOs were analyzed by gas chromatography coupled to mass spectrometry (GC/MS). Their antioxidant, antifungal and phytotoxic properties were investigated. All EOs displayed a specific richness in eucalyptol (75.94-7.01%), camphene (6.97-0.4%) globulol (5.20-5.83%) and α-pinene (0.71-12.82 %). EOs isolated from E. populifolia exhibited significant antioxidant activity. Furthermore, all investigated EOs displayed significant antifungal properties against four phytopathogenic fungi belonging to Fusarium genus. The phytotoxic activity against five weeds showed varying effectiveness on seed germination and seedling growth, which exhibited greater effectiveness compared to glyphosate. Eucalyptus EOs have the potential to be used in the formulation of biopesticides.
