THE PHENOLIC COMPOUNDS EXTRACTED FROM Rosmarinus officinalis L. AND EFFECT OF ON THE BIOFILM GENES IN Pseudomonas aeruginosa COMPONENTS

The emergence of antibiotic resistance has made microbial infections one of the biggest public health issues in the world, and this has prompted researchers to look into the antibacterial properties of medicinal plants. Therefore, this study aimed to extract phenolic compounds from Rosmarinus officinalis and study their effect on some virulence genes responsible for biofilm formation in Pseudomonas aeruginosa. Ten p. aeruginosa isolates were collected from the Genetic Engineering and Biotechnology Institute/University of Baghdad labs. The isolates were cultured on cetrimide agar and identified using the VITEK-2 system. Aqueous and methanolic extracts of Rosmarinus officinalis leaves were made using the maceration technique and the Soxhlet equipment, respectively. Several experiments were conducted on the extracts including high performance liquid chromatography (HPLC), biofilm formation using the micro-titter plate method, and the expression of algD and pelA genes by comparing the isolates treated with methanolic and aqueous extracted with untreated isolates. The HPLC results showed four phenolic acids (gallic, rosmarinic, ferulic and caffeic) were found by comparing them to the retention times of the reference standards. The result of biofilm formation in P. aeruginosa revealed that 100 % of the isolates were strong biofilm formation. In addition, the treatment with the aqueous extract of the Rosmarinus officinalis inhibits the biofilm formation in 16 mg/ml, while the biofilm formation was inhibited by the methanolic extract in 64 mg/ml. The virulence genes algD and pelA responsible for biofilm formation in P. aeruginosa were investigated. The results showed the presence of these genes in all isolates. The gene expression results showed low levels of algD and pelA genes after being treated with the aqueous and methanolic extracts compared to the untreated isolates.