Phytochemical Characterization and Bioactivity of Diethyl Ether Fractions of Ocimum Gratissimum Against Enteric Pathogens

The increasing emergence of antibiotic-resistant enteric pathogens has renewed global interest in medicinal plants as alternative sources of antimicrobial agents. This study investigated the phytochemical characterization and antibacterial activity of diethyl ether fractions of Ocimum gratissimum (scent leaf) against clinically relevant enteric bacteria. Fresh leaves of O. gratissimum were subjected using Soxhlet apparatus with ethanol, followed by liquid-liquid partitioning with diethyl ether to isolate non-polar bioactive fractions. Bacterial identification was performed using morphological characteristics, gram staining, and biochemical tests. The antibacterial efficacy of both ethanol extract and diethyl ether fraction was evaluated using the agar disc diffusion method against Escherichia coli, Salmonella typhi, and Klebsiella pneumoniae. The results demonstrated concentration-dependent inhibitory activity of both extracts against E. coli and S. typhi, with zones of inhibition ranging from 8.0 mm to 15.0 mm. No activity was recorded against K. pneumoniae, possibly due to its protective capsular structure that hinders phytochemical penetration. Notably, the ethanol extract demonstrated higher antimicrobial activity compared to the diethyl ether fraction. Phytochemical characterization using Gas Chromatography-Mass Spectrometry (GC-MS) analysis both ethanol extract and diethyl ether fraction revealed 47 distinct compounds, including eugenol, phytol, caryophyllene, phenols, and benzotriazoles molecules which are known to disrupt microbial membranes and inhibit essential enzymes. Although the diethyl ether fraction showed promising antibacterial effects, its potency was lower than that of the ethanol extract and standard antibiotic (ciprofloxacin), highlighting the benefits of broader-spectrum solvent extractions. This study supports the ethnomedicinal relevance of O. gratissimum in managing gastrointestinal infections and presents it as a potential source of plant-derived antimicrobial agents. Further studies are recommended to isolate active compounds, understand synergistic interactions, clarify mechanisms of action, and perform in vivo evaluations to establish efficacy and safety. The findings contribute to ongoing efforts in phytopharmacology and the development of alternatives to synthetic antibiotics.