Antibacterial effects of fresh onion (Allium cepa L.) bulbs against clinical bacteria

Abstract

The purpose of study was to determine the effects of fresh onion bulbs extracts on pathogenic bacteria in an attempt to seek active components presentin the onion bulbs. Standard procedures were used for plant extraction and antibacterial susceptibility tests. The extracts were active against Escherichia coli, Staphylococcus aureus, Streptococcus Spp and Enterococcus Spp. while Pseudomonas aeruginosa and Bacillus subtilis were resistant to plant extracts and standard antibiotics. Minimum inhibitory concentration were 25mg/ml and 50mg/ml respectively for ethanol and methanol extracts for E. coli and Streptococcus Spp. The phytochemical results indicated the presence of saponins phenols, tannins, steroid, alkaloids, cardiac glycosides and flavonoid. Anthraqinone and terpenoid were absent. Conclusively, water extracts of fresh onion bulbs was not potent against clinical isolates however ethanol and methanol extracts were active. Fresh onions bulb extracts contained low concentrations of phytochemical compounds.