Investigation of Antimicrobial Potential of Medicinal Plants Against <i>Pseudomonas aeruginosa</i>

<i>Pseudomonas aeruginosa</i>, a gram-negative bacterium present in water and soil, causes significant illnesses and chronic conditions that degrade drinking water quality. This study aimed to evaluate the antibacterial and antioxidant activities of plant extracts (<i>Convolvulus arvensis</i>, <i>Chenopodium murale</i>, <i>Avena fatua</i>, <i>Cirsium arvense</i>, and <i>Hordeum vulgare</i>) against <i>P. aeruginosa</i>. FTIR spectroscopy was used to investigate in the plant extracts, and the phytochemical compounds found in the plant extracts were analyzed using GC-MS analysis. This study evaluated the antioxidant activity of plant extracts using DPPH scavenging assays and found that ascorbic acid significantly improved the DPPH scavenging activity of <i>C. arvensis</i> extract compared to that of other plants. Saliva samples were collected from the patients to differentiate <i>P. aeruginosa</i> from other oral cavity microorganisms. Gram staining and catalase testing were performed to identify bacterial strains. <i>Pseudomonas aeruginosa</i> produces a positive catalase test and appears as a pink or red rod after Gram staining. This study revealed that five plant extracts have antibacterial activity against <i>P. aeruginosa. Cirsium arvensis</i> showed a higher zone of inhibition (72 mm). The MIC was the lowest concentration that inhibited the visible growth of a bacterium, whereas the MBC was the lowest concentration that killed 99.9% of the bacteria. <i>A. fatua</i> and <i>C. murale</i> were effective at very low concentrations, inhibiting bacterial growth at 1 μg/mL and killing bacteria at 2 μg/mL. <i>Hordeum vulgare</i> and <i>C. arvense</i> require slightly higher concentrations to effectively inhibit bacterial growth and to exert bactericidal effects. All the studied plant extracts were effective in inhibiting biofilm formation by <i>P. aeruginosa</i>; however, <i>H. vulgare</i> demonstrated the highest percentage of inhibition (99.05) at a concentration of 0.8 μg/mL. This study revealed that these plants exhibit antibacterial activity against <i>P. aeruginosa</i>.