Regional Differences in Phytochemical Profiles and Antimicrobial Efficacy of Ocimum tenuiflorum L. Essential Oil.

BOTANY AND MICROBIOLOGY

Medicinal plants represent an important source of bioactive compounds with potential applications in antimicrobial therapy. In the present study, the chemical composition and antibacterial activity of essential oil extracted from Ocimum tenuiflorum L. leaves collected from two different geographical regions were investigated. Essential oils were obtained by hydrodistillation using a Clevenger apparatus and analysed by gas chromatography–mass spectrometry to determine their phytochemical profiles. Antibacterial activity was evaluated against Staphylococcus aureus, Bacillus subtilis, Escherichia coli, and Pseudomonas aeruginosa using the agar well diffusion method, minimum inhibitory concentration determination, and bacterial growth curve analysis under sub-inhibitory conditions. GC–MS analysis revealed distinct variations in chemical composition between the urban and rural samples, with eugenol and methyl eugenol identified as the major constituents. Both essential oil samples exhibited inhibitory effects against all tested bacterial strains, with the rural sample showing comparatively higher antibacterial activity. Growth kinetic studies demonstrated a significant reduction in bacterial proliferation in the presence of essential oils, indicating significant suppression of bacterial growth. The results suggest that geographical origin influences both the phytochemical composition and antibacterial efficacy of Ocimum tenuiflorum L. essential oil. This study highlights the role of environmental factors in determining the antimicrobial potential of plant-derived essential oils and supports their possible application as natural antibacterial agents.

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