Survival of some microorganisms in the presence of onion (allium cepa l.) extracts in vitro

Abstract

By using disc diffusion assay, the antibacterial and anticandidal activities of extracts prepared from two varieties of onion (red and white) with water and different solvent extracts (ethyl alcohol, methyl alcohol, acetone and diethyl ether) at different concentrations (800, 400, 200 and 100 mg/mL) were evaluated against six bacteria: Enterobacter aerogenes (ATCC 13048), Escherichia coli (ATCC 25922), Salmonella enteritidis (ATCC 13076), Salmonella typhimurium (ATCC 14028), Staphylococcus aureus ssp. aureus (ATCC 29213), Bacillus subtilis (test microorganism of sterilization) and one genus of yeast Candida albicans (ATCC 10231). The research clearly indicates that white Allium cepa (diethyl ether, water and methyl alcohol) and red Allium cepa (diethyl ether, methyl alcohol, water and acetone) extracts were inhibitory against the tested microorganisms. White Allium cepa extract of ethyl alcohol at 800 mg/mL dose was found to be able to inhibit Candida albicans and other extracts were definitely non-inhibitory (p<0.01).