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|Title||Antimicrobial, Anti-biofilm, Anti-Quorum Sensing and Synergistic Effects of Some Medicinal Plants Extracts.|
|Title in Arabic||التأثيرات المضادة للميكروبات، للأغشية الحيوية، لإستشعار النصاب والتأثير التآزري لبعض مستخلصات النباتات الطبية.|
Abstract Background: A biofilm is the assembly of microbial cells that are entrapped in an extracellular polymeric substance matrix. Using complex mechanisms produced by specialized genes, biofilm members are able to talk, communicate, exchange experiences and virulence factors with each other according to a phenomenon called quorum sensing (QS). Biofilm formation by bacteria is a major factor in pathogenesis and in survival. Multidrug resistance phenomenon is increasing and no or very few new antibiotics are being discovered so attention is being turned to use other alternatives, including the use of medicinal plants as antimicrobials and/or as anti-biofilm. Objective: The main objective of this study is to screen locally available medicinal plants for their In Vitro antibacterial, anti-biofilm, anti-quorum sensing and their synergistic activity. Methods: Extracts from the dried aerial parts of plants were prepared using 70% ethanol in soxhlet apparatus. All extracts were screened for their antibacterial and antifungal activity, determination the minimum inhibitory concentration, anti-biofilm activity, anti-quorum sensing using (swarming method, altered pyocyanin production quantitative assay, Las A staphylolytic assay), and synergistic effect in combination with commercially available antimicrobials. Results: The average diameter of inhibition zone resulted from the various plant extracts against the tested bacteria ranged from 0 to 22 mm, while the range against Candida albicans was 0 to 52 mm. The average minimum inhibitory concentration (MIC50) value ranged from 0.3-81.3 mg/ml against Pseudomonas aeruginosa, 0.02-20.8 mg/ml against C. albicans. Pelargonium hortorum exhibited the highest antimicrobial activity. Agave sisalana has the highest anti-biofilm activity against the test microorganism, with 87.5% reduction in biofilm formation. Screening for anti-quorum sensing assay using swarming method showed that P. hortorum has the best inhibition of motility of the P. aeruginosa isolate 1, while Punica granatum has the best motility inhibition of P. aeruginosa isolate 2. Prominent alteration of pyocyanin production quantitative assay was observed with Artemisia absinthium and Hibiscus sabdariffa as evident by the reduction of the green colored (pyocyanin) pigment in P. aeruginosa. Plant extracts showed variable abilities in reducing the las A protease activity of P. aeruginosa. Momordica charantia showed the greatest reduction in activity (77.1%). The synergistic effect of plant extracts when combined with different antimicrobials showed variable activity against Staphylococcus aureus. Cinnamomum zeylanicum had the best synergistic effect against S. aureus. Conclusions: Most of the studied plant extracts showed the ability to inhibit antibacterial and antifungal activities. Anti-biofilm and anti-quorum sensing activity were also demonstrated. In addition, synergistic activity of these extracts with commercial antimicrobials showed promising results. Further studies are required to determine the active components and the LD50 of these extracts. Key words: Anti-biofilm, Antibiotic resistance, Plant extract and biofilm, and Quorum sensing, Gaza- Palestine.
|Publisher||الجامعة الإسلامية - غزة|
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