SUMMARY
A biofilm is the assembly of microbial cells that are entrapped in an extracellular polymeric substance matrix. Biofilm members are able to talk, communicate, exchange virulence factor with each other according to quorum sensing. Biofilm formation by bacteria is a major factor in pathogenesis and in survival. The objective is to screen plants for their In Vitro antibacterial, anti-biofilm, and anti-quorum sensing. Extracts from the dried aerial parts of plant were prepared using 70% ethanol. All extracts were screened for their antibacterial and antifungal activity, determination the MIC50, anti-biofilm activity, anti-quorum sensing, and synergistic effect. The diameter of inhibition zone resulted from the plant extracts against the bacteria ranged from 0 to 22 mm, while against fungal was 0 to 52 mm. The MIC50 ranged from 0.3-81.3 mg/ml against Pseudomonas aeruginosa, 0.02-20.8 mg/ml against fungal. Pelargonium hortorum exhibited the highest antimicrobial activity. Agave sisalana has the highest anti-biofilm activity, with 87.5% reduction. Screening for anti-quorum sensing assay showed that P. hortorum and Punica granatum has the best inhibition of motility of the P. aeruginosa. Artemisia absinthium and Hibiscus sabdariffa has the greatest reduction of the pyocyanin pigment in P. aeruginosa. Momordica charantia showed the greatest reduction in activity of lasA protease (77.1%). Cinnamomum zeylanicum had the best synergistic effect. Most of the studied plant extracts showed the ability to inhibit antibacterial antifungal activities anti-biofilm and anti-quorum sensing. Further studies are required to determine the active components and the LD50 of these extracts.