Hanan Abdullah Ali, Zainab Salim Hussin, Sadik Kadhim Taaban, Ilham Abdul Hadi Khalaf, Moamer Talib Hamad and Jamal Salman Chaiad
Department of Microbiology, College of Science, AL-Kharkh University for Science, Iraq
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(Received : April 23, 2021; Accepted : June 12, 2021)
The anti-microbial activity of three alcoholic extracts of nettle (Urtica dioica), milk thistle (Sylibium marianum) and oregano (Origanum vulgare) plants, with different concentrations (5, 10, 15 and 20 mg/ml), were
estimated against some types of bacteria that caused food poisoning, including Staphylococcus aureus, Pseudomonas aeruginosa, Shigella dysenteriae, Escherichia coli, Salmonella typhi, Klebsiella pneumoniae, Bacillus subtillus and Candida lipolytica yeast, by using agar gel diffusion technique in plates. The alcoholic extracts of U. dioica, S. marianum and O. vulgare exhibited varying antagonistic efficacy against gram positive and negative bacterial isolates and C. lipolytica. The inhibition rates raised with increasing concentrations and the most effective impact were observed at 20 mg/ml for all extracts, which achieved the highest rate of inhibition diameters 22, 20, 23, 22, 21, 22, 23 and 22 mm against S. aureus, S. typhi, S. dysenteriae, E. coli, P. aeruginosa, C. lipolytica, B. subtillus and K. pneumonia, respectively, for nettle extract, while the rates of inhibition diameters when using the milk thistle plant extract reached 22, 19, 18, 23, 22, 19, 20 and 21 mm. However, the extract of oregano plant achieved inhibition rates 19, 20, 20, 20, 22, 20, 19 and 21 mm, respectively. On the other hand, the concentrations 5, 10 and 15 mg/ml showed inhibition efficiency, but lower than the concentration 20 mg/ml. The plant extracts used in the study were effective in inhibiting the growth of pathogenic isolates, which made it possible to use as a natural inhibitor for preserving food and controlling the growth of pathogenic microorganisms, because it contained natural active compounds that acted as an alternative to chemical preservatives that had side effect reflections on human health.
Key words : : Alcoholic extracts, pathogenic microorganisms, Urtica dioica, Sylibium marianum and Origanum vulgare, food diseases