Chemical profile and bioactivity enhancement of Eucalyptus camaldulensis essential oils through hybridization and rectification: A chemometric and molecular docking study

Abstract

The rectification of essential oils (EOs) through fractional distillation emerges as a promising approach for enhancing their compositional quality and biological efficacy. This physicochemical separation process enables the selective concentration of desirable bioactive compounds while simultaneously reducing the presence of unwanted constituents, thereby yielding fractions with optimized chemical profiles. This study investigated the semi-industrial rectification effects on EOs from Eucalyptus camaldulensis leaves and its hybrid Clone 583 through fractional distillation. Chemical analysis revealed higher yield in the hybrid (0.75 %) compared to the parent species (0.46 %), with 1.8-cineole and α-pinene identified as principal compounds among 38 detected constituents. Rectification yielded higher 1.8-cineole concentrations in hybrid fractions (85 % vs. 59 %) while reducing α-pinene content (5.10 % vs. 19.20 %). Clone 583 exhibited superior antibacterial activity against M. smegmatis (F_c: 76.36 ± 0.08 mm vs. F₆: 68.36 ± 0.17 mm) and enhanced antioxidant properties in DPPH assays (IC₅₀: F_c: 25.21 ± 0.05 µg/ml vs. F₆: 44.00 ± 0.08 µg/ml). Principal Component Analysis and Hierarchical Cluster Analysis indicated 1.8-cineole as the primary contributor to antioxidant activity, while molecular docking suggested that both 1.8-cineole and α-pinene exert antibacterial effects through LasR-OC12 binding. These findings demonstrate that the combination of hybridization and rectification techniques present significant potential for various industrial applications, particularly in pharmaceutical, cosmetic, and food preservation sectors, where high-purity bioactive compounds are essential.