Phytochemical characterization and Antibacterial Efficacy of Two Essential Oils: GC-MS Profiling, In Vitro Antibacterial Testing, and In Silico ADMET, Molecular Docking, and Molecular Dynamics Simulation
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Date
2025
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جامعة الوادي university of eloued
Abstract
Medicinal plants serve as a prolific source of bioactive compounds with diverse biological
activities, positioning them as a pivotal focus in research related to alternative medicine and
pharmacology. This study investigates the phytochemical composition and antibacterial
potential of essential oils derived from Cotula cinerea and Origanum Majorana L., two
medicinal plants native to the El Oued region of Algeria and traditionally used in folk remedies
for various ailments.
The essential oils exhibited promising antibacterial properties, distinguished by their
unique chemical profiles and notable efficacy. Using hydrodistillation, the extraction yield of
Origanum Majorana L. oil reached 1.45%, compared to 0.90% for Cotula cinerea, with
variations influenced by geographical factors such as soil composition and climate. Gas
Chromatography-Mass Spectrometry (GC/MS) analysis identified trans-thujone as the
predominant compound, accounting for 51.86% of Cotula cinerea oil and 33.3% of Origanum
Majorana L. oil, along with santolina triene (16.4%) in the latter. These results underscore
notable chemical differences compared to prior studies conducted in other regions.
In biological assays, Origanum Majorana L. oil demonstrated superior antibacterial
activity, achieving a 25.6 mm inhibition zone against S. aureus, significantly outperforming
amoxicillin, which exhibited a mere 0.1 mm zone. Furthermore, IC₅₀ values highlighted the oils'
potency, with Origanum Majorana L. displaying an IC₅₀ of 1.5 mg/mL against E. coli,
compared to 3.96 mg/mL for amoxicillin.
Computational studies corroborated the experimental findings. Molecular docking
revealed that trans-thujone interacts strongly with bacterial protein active sites, particularly
binding to HIS299 and ASP197 residues in E. coli, with a binding energy of -9.5 kcal/mol,
indicating its potential to disrupt bacterial functions. Molecular Dynamics Simulations (MDS)
further validated the stability of this interaction over a 100-nanosecond period, characterized
by minimal atomic fluctuations (RMSD < 2 Å), reinforcing its candidacy as a potential
therapeutic agent.
Regarding pharmacological safety, ADMET predictions indicated low toxicity for the
principal compounds (classified under Toxicity Class 5) and favorable blood-brain barrier
(BBB) permeability, without susceptibility to P-glycoprotein (P-gp) efflux. Nevertheless,
compounds such as cis-Verbenyl acetate demonstrated inhibition of the CYP2C9 enzyme,
suggesting the need for further investigation into possible drug interactions.
Description
Keywords
Essential oils, Cotula cinerea, Origanum Majorana L., Antibacterial activity, GC/MS analysis, Molecular Docking, Molecular Dynamics Simulations, ADMET properties, trans-thujone compound.
Citation
master, 2025. DEPARTEMENT DE BIOLOGIE CELLULAIRE ET MOLECULAIRE. Faculté des Sciences de la Nature et de la Vie. Université d'El-Oued.