Chemical Composition and In Vitro Antioxidant and Antibacterial Activities of Eucalyptus camaldulensis Leaf Essential Oil from Northwestern Libya

Abstract

This study investigates the phytochemistry, antioxidant capacity, and antibacterial activity of Eucalyptus camaldulensis essential oil (EEO) cultivated in northwestern Libya. The volatile profile was analyzed via gas chromatography-mass spectrometry (GC-MS). The analysis identified 1,8-cineole (33.61%) and α-pinene (29.90%) as the principal constituents of the observed chemical profile. Antioxidant activity was evaluated using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging assay, which demonstrated a weak antioxidant potential (IC50 > 10,000 µg/mL). Conversely, preliminary antibacterial screening via the disc diffusion method demonstrated variable, strain-dependent growth-inhibitory effects across five standard reference strains. The most pronounced susceptibility was observed against the Gram-positive strain Staphylococcus aureus (20 mm zone of inhibition). These findings successfully fill a localized geographic evidence gap by providing foundational phytochemical data for North African E. camaldulensis. Furthermore, this study highlights a distinct monoterpene-dominant profile that contrasts sharply with the chemical polymorphism frequently observed in other widely cultivated regional species such as E. globulus, providing valuable chemotaxonomic context without implying strict geographic causation or direct pharmaceutical efficacy.