Antimicrobial and Antioxidant Properties of <i>Sambucus nigra</i> L. (Elderflower) Oil: A Molecular Docking and Biochemical Study

The present study investigates the antimicrobial and antioxidant potential of an essential oil extracted from <i>Sambucus nigra</i> L. flowers. Using hydrodistillation, the volatile compounds were profiled through GC–MS analysis for the fatty acid profile and volatile compounds. The fatty acid profile demonstrated a balanced composition of saturated fatty acids, monounsaturated fatty acids, and polyunsaturated fatty acids, with oleic, palmitic, and linolenic acids as key contributors. The volatile profile revealed the dominance of nonanal, <i>cis</i>-rose oxide, <i>trans</i>-rose oxide, and 2-Pentadecanone, 6,10,14-trimethyl-. Antioxidant activity was assessed using the 1,1-Diphenyl-2-Picrylhydrazyl radical scavenging assay, showing significant inhibition, with an IC₅₀ value of 2.52 mg/mL. Antimicrobial efficacy was determined against Gram-positive, Gram-negative, and fungal strains, highlighting moderate inhibitory activity for <i>Streptococcus pyogenes, Staphylococcus aureus</i>, and <i>Candida albicans</i>. The <i>S. nigra</i> essential oil exhibited more activity against fungal strains, especially <i>C. albicans</i>, compared to the bacterial strains, which might be attributed to differences in the composition and permeability of the cell wall between fungi and bacteria. Among the bacteria, <i>E. coli</i> was the most susceptible, while <i>P. aeruginosa</i> showed moderate resistance, in agreement with its known stronger membrane structure and efflux mechanisms. Molecular docking analysis was conducted to evaluate the potential inhibitory effects of the oil on microbial proteins to corroborate the observed in vitro outcome. The results indicated that nonanal, <i>cis</i>-rose oxide, <i>trans</i>-rose oxide, and 2-pentadecanone, 6,10,14-trimethyl- displayed interesting hydrophilic and hydrophobic binding interactions with the putative microbial proteins. These findings elucidate the bioactive role of <i>Sambucus nigra</i> essential oils, suggesting their potential as therapeutic agents in managing oxidative stress and microbial infections.