University of Guilan Caspian Journal of Environmental Sciences 1735-3033 22 1 2024 01 01 Anatomical study with antibacterial and antibiofilm effects of Erodium cicutarium (L.) L'H phenolic roots extract 137 146 6762 10.22124/cjes.2023.6762 EN Zubaida A. Lattef Ismaeel Department of Biology, AL-Iraqia University, Baghdad, Iraq Journal Article 2023 06 16  Bacteria acquire resistance to antibacterial drugs, so there is always a need for new drugs to inhibit many human bacterial pathogens. Novel studies were carried out to examine the internal structures as well as the antibacterial effect of <em>Erodium cicutarium</em> phenolic root extracts (APR) on the development of biofilm formation of bacterial species, <em>Klebsiella pneumoniae</em> and <em>Staphylococcus aureus</em> using four strains from both clinical and environmental samples <em>in vitro</em>. Anatomy of all the vegetative parts showed a presence of tannin-filled cells in their structures. Also, the experiments were conducted to study the antibacterial effect by determining the minimum inhibitory concentrations (MICs), and susceptibility test of these strains for five antibiotics. Although the APR concentrations of 50, 25, 12.5, 6.25, 3.125, and 1.625 μg mL^-1; W/V) were used through antibiotic and biofilm inhibition assay. The result of sensitivity test showed more resistant to various antimicrobial especially Amoxicillin, Cephalothin and Methicillin for both bacterial strains. In addition, the MICs tested showed that the ranged values were in concentrations between 0.017 to 0.650 mg mL^-1 for both <em>K. pneumoniae </em>and <em>S. aureus </em>strains. Furthermore, biofilm reduction assay results for treatments showed that the highest activity was obtained with phenolic root extracted, biofilm eradication at 1.3 mg mL^-1. In conclusion, the results showed that relatively low concentrations of phenolic root extracts displayed promising antibacterial and antibiofilm capabilities making them attractive for additional studies as “novel therapeutic agents.”<strong> </strong><br /><strong> </strong> https://cjes.guilan.ac.ir/article_6762_3ea53f47b18020e93b26e83893fcef5c.pdf