EVALUATION OF ANTIBACTERIAL ACTIVITY OF ETHANOLIC EXTRACT OF NEEM LEAVES (AZADIRACHTA INDICA) AGAINST ESCHERICHIA COLI AND CLOSTRIDIUM SPP.
Abstract
The emergence of antibiotic-resistant bacteria has prompted increased interest in plant-based
alternatives with antimicrobial potential. This study investigates the antibacterial activity of
ethanolic extracts of Azadirachta indica (Neem) leaves against Clostridium spp. and Escherichia
coli, using the disc diffusion method. Neem leaves were shade-dried, powdered, and extracted with
ethanol using a Soxhlet apparatus. The extract was tested at concentrations of 10%, 25%, 50%,
and 100% to assess dose-dependent antibacterial effects. Standard antibiotics—Metronidazole and
Ciprofloxacin—served as positive controls for Clostridium spp. and E. coli, respectively. The
ethanolic extract exhibited concentration-dependent antibacterial activity against both test
organisms, with the highest inhibition zones observed at 100% concentration. Clostridium spp.
showed greater sensitivity to the Neem extract compared to E. coli. When compared to standard
antibiotics, Metronidazole was more effective against Clostridium spp., while Ciprofloxacin
showed higher activity against E. coli. These findings suggest that Neem leaf extract possesses
notable antibacterial properties and could serve as a natural alternative or complementary
treatment, especially for infections involving Gram-positive and Gram-negative bacteria. Further
studies are recommended to isolate the active compounds and evaluate their therapeutic potential.
KEYWORD: Azadirachta indica, Antimicrobial activity Antibiotics resistance Escherichia
coli and Clostridium spp.
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