Antibacterial Effect of Flavonoids Extracted from Seeds of Silybum marianum against Common Pathogenic Bacteria

Abstract

This research was carried out to evaluate the antibacterial effect of Silybum marianum flavonoids extracted from seeds on pathogenic bacteria (Staphylococcus saprophyticus, Escherichia coli, Staphylococcus aureus and Klebsiella pneumoniae) and detect the bioactive compounds found in the seed extract. Different methods were used to tech the aims of the study. Agar well diffusion method and mixed up the extract with agar media were used to evaluate the antibacterial activity of the flavonoids extracted from seeds of S. marianum. The chemical analysis to seeds showed that it contained several antibicrobial compounds such as terpenoids, flavonoids and tannins. The cold alcoholic extract of milk thistle did not appear significant antibacterial activity against the bacterial isolates when agar well diffusion method was used while mixing the seed extracts with agar media showed antibacterial activity (1500-2900 μg/ml) against S. sprophyticus, E. coli, K. pneumoniae and S. aureus.