Green Extraction of Citrus sinensis (L.) Osbeck Peel Essential Oil and Its Impact on Antioxidant and Antimicrobial Activity: Supported by Molecular Docking and DFT Analysis

Citrus sinensis (L.) Osbeck ( C. sinensis ) peel is a rich source of essential oil ( EO ) widely used in pharmaceutical, food, and aroma industries; however, effective extraction strategies and molecular insights remain unexplored. This study presents superheated steam extraction ( SHSE ) as a novel green approach for the C. sinensis EO extraction and its comparison with conventional hydro and steam distillation methods. The chemical profile and bioactivities were analyzed and further strengthened by molecular docking and DFT studies. A maximum yield of 0.20% (w/w) was obtained through SHSE . Volatile composition, studied by GC – MS , identified d‐limonene (8.84% to 30.72%) as the primary compound. Several tests, including resazurin microtiter plate assay, agar well diffusion, and microdilution broth assay, were performed to evaluate the antimicrobial potential. The SHS extracted EO exhibited maximum antibacterial and antifungal activity. Antioxidant properties of the extracted EOs were determined by employing the DPPH assay, hydrogen peroxide scavenging assay, and the FRAP assay. Superheated steam extracted EO also revealed the highest antioxidant activity. Molecular docking was performed to evaluate the ligand–protein interactions. All compounds showed lower binding energies; among them, four compounds, d‐limonene, trans ‐carvyl acetate, β‐terpinyl acetate, and α‐himachalene, were found as significant binders to the targeted antioxidant and antimicrobial proteins. DFT studies were performed at the B3LYP /6– 31G (d,p) level to elucidate the compound's antioxidant mechanism of action. DFT predicted β‐terpinyl acetate as the most effective antioxidant candidate, attributed to its lowest energy gap (6.7616 eV ), highest chemical softness, and lowest chemical hardness. Overall, it is concluded that SHSE gave the highest EO yield while biological assays provided the synergistic performance of EO components which is justified by combining with computational analysis.