Antibacterial activity of Ocimum gratissimum (scent leaf) extracts on selected bacteria isolates

Background: Ocimum gratissimum is a plant rich in bioactive compounds believed to possess antimicrobial, anti-inflammatory, analgesic, and antioxidant effects. This study was carried out to determine the antibacterial activity of Ocimum gratissimum extracts on selected bacteria isolates. Methods: This was a prospective clinical and laboratory study in which bacteria swabs were collected from patients who presented with bacterial conjunctivitis at the Eye Clinic, Department of Optometry, Federal University of Technology, Owerri, Nigeria and transported to the Microbiology Laboratory at Federal University Teaching Hospital, Owerri for culturing and isolation. The zones of inhibition of ethanolic and aqueous extracts of Ocimum gratissimum on three bacteria isolates from the swab samples was tested for antibacterial activity. Results: The mean zones of inhibition for 100 mg/ml ethanolic extract of Ocimum gratissimum was 18.96 ± 0.20 mm on S. aureus, 16.35 ± 0.28 mm on E. coli, and 17.80 ± 0.37 mm on K. pneumonia. For 100 mg/ml aqueous extract of Ocimum gratissimum, the mean zones of inhibition was 5.17 ± 0.17 on S. aureus, 3.82 ± 0.21 mm on E. coli, and 3.80 ± 0.20 mm on K. pneumonia. There was a significant antibacterial effect (p < 0.001) of both the ethanolic and aqueous extracts of Ocimum gratissimum on the selected bacteria isolates. Conclusion: Both ethanolic and aqueous extracts of Ocimum gratissimum showed antibacterial activity on the selected bacteria isolates. These findings support the potential of Ocimum gratissimum as alternative therapeutic agent against drug-resistant bacteria.