Acetylcholinesterase, Antibacterial, Antiplatelet Aggregation, Membrane-Disruptive and Metabolic Enzyme Inhibitory Activities of Essential Oil from the buds of Syzygium aromaticum (L.) Merr. & L.M.Perry

The increasing prevalence of antimicrobial resistance and metabolic disorders necessitates the exploration of natural products with multifunctional biological activities. This study investigated the chemical composition and pharmacological properties of essential oil obtained from the dried flower buds of Syzygium aromaticum (L.) Merr. & L.M. Perry (clove). The essential oil was extracted by hydrodistillation and analyzed by gas chromatography–mass spectrometry (GC–MS). Biological activities were evaluated through antibacterial, membrane-disruptive, antiplatelet aggregation, acetylcholinesterase and metabolic enzyme inhibitory assays. GC–MS analysis revealed the predominance of phenylpropanoids (92.8%), with eugenol (91.7%) as the major constituent. The essential oil exhibited broad-spectrum antibacterial activity against selected Gram-positive and Gram-negative bacteria, producing significant growth inhibition. Mechanistic studies demonstrated that the oil compromised bacterial membrane integrity, leading to increased membrane permeability and leakage of intracellular constituents. In addition, the oil significantly inhibited platelet aggregation induced by common agonists (IC₅₀ = 1.05 to 3.55), compared to Aspirin (IC₅₀ = 1.88 to 4.20), indicating potential antithrombotic properties. The essential oil also showed marked inhibitory activity against acetylcholinesterase, suggesting possible neuroprotective relevance in the management of cholinergic dysfunction. Furthermore, the oil inhibited key metabolic enzymes associated with carbohydrate and lipid metabolisms, supporting its potential role in the management of metabolic disorders. These findings highlight the multifunctional pharmacological potential of S. aromaticum flower bud essential oil as a natural source of antibacterial, antiplatelet, neuroactive, and metabolic enzyme inhibitory agents. Further in vivo studies and toxicological evaluations are warranted to validate its therapeutic applications and elucidate the underlying molecular mechanisms.