In-vitro Antibacterial Activity of Moringa oleifera Leaf Extract Against Staphylococcus aureus and Escherichia coli Using Disc Diffusion Method

Abstract

Infectious diseases caused by pathogenic microorganisms remain an important public health concern, while the misuse and overuse of antibiotics contribute to antimicrobial resistance. Medicinal plants contain various phytochemicals and have traditionally been used for the management of infectious conditions. The present study evaluated the in-vitro antibacterial activity of Moringa oleifera leaf extract against Staphylococcus aureus and Escherichia coli using the disc diffusion method. Leaves of M. oleifera were collected from the Botanical Garden of Lydia College of Pharmacy, East Godavari District, Andhra Pradesh, authenticated, dried, powdered and extracted with ethanol. Preliminary phytochemical screening was performed, and the antibacterial activity of the extract was evaluated at concentrations of 100, 200, 300, 400 and 500 mg/mL using 6-mm filter-paper discs containing 20 µL of test solution on Mueller–Hinton agar. S. aureus and E. coli were identified using morphological, staining and biochemical characteristics, and Ciprofloxacin was used for comparison. The extract showed measurable antibacterial activity against both organisms, with inhibition zones against S. aureus of 8, 10, 12, 14 and 16 mm, and against E. coli of 7, 9, 11, 13 and 15 mm at the respective concentrations. Ciprofloxacin produced inhibition zones of 16–24 mm against S. aureus and 15–23 mm against E. coli. Phytochemical screening indicated the presence of carbohydrates, proteins, alkaloids, glycosides, saponins, tannins, flavonoids and polyphenolic constituents. The findings demonstrate measurable in-vitro antibacterial activity of ethanolic M. oleifera leaf extract against both test organisms, with increasing inhibition-zone diameters at higher extract concentrations. Further studies are required to investigate the active antibacterial constituents and their potential applications.