Evaluation of the antibacterial activity of oily extracts of the grains of two varieties of red onion from Morocco

The aim of the present work is to evaluate the antibacterial activity of the oils extracted from the seeds of two varieties of red onion Doukkala and Amposta using hexane and ethanol. The ethanol extracts are more active than hexane extracts vis-a-vis bacteria gram+ tested (Staphylococcus aureus CIP 53154, Enterococcus faecalis CIP 103214, Bacillus cereus and Streptococcus A IPL141 IPT 5-84) and gram- (Escherichia coli CIP 54127, Enterobactersp, Pseudomonas aeruginosa CIP A 22 and Salmonella typhi CIP 5535). The MICs determined by the well-diffusion method for each extract show that the ethanolic oil extracts are bactericidal towards Staphylococcus aureus (SASM) and Staphylococcus aureus (SARM) strains. This could be explained by the fact that the ethanolic extracts are richer in polyphenols (98.7 ± 0.2 mg EGA / g extract) for Doukkala ethanol extract (EED) and (85.7 ± 0.2 in mg of EGA / g of extract) for the ethanolic extract of Tetouan (EET) (Amposta) which is also bactericidal with respect to the Bacillus cereus strain and this for a MIC of 0.125 mg / mL. The strain Enterobacter is sensitive in all the extracts while the 6-aminopenicillanic acid antibiotic 6-APA is not sensitive.