Antibacterial and Anti-Biofilm Activity of Selected Plant Extracts Against Some Human Pathogenic Microorganisms

摘要

Background and Objective: Biofilm is a complex microbial community highly resistant to antimicrobials agents. The formation of biofilms in biotic and abiotic surfaces is associated with high rates of morbidity and mortality and considered as a major factor of bacterial pathogenicity. In the present study the antimicrobial and antibiofilm activities of 5 plant extracts ( Glycyrrhiza glabra roots, Laurus nobili , Malus domestica peels, Melissa officinalis and Lagenaria siceraria peels) were evaluated against clinical isolated microorganisms ( E. coli , S. aureus , P. aeruginosa and K. pneumonia ). Materials and Methods: The extracts of medicinal plant s were prepared using microwave assisted method by ethanol and water. Results: The results of this study revealed that, the aquatic extract of M. domestica peels showed powerful antimicrobial activity against E. coli with MIC value 1.56 mg mLsup?1/sup, the ethanolic extract of G. glabra roots showed good antimicrobial activity against P. aeruginosa with minimum inhibitory concentration (MIC) of 12.5 mg mLsup?1/sup. Most plant extracts in this study gave the minimum bactericidal concentration (MBC) ≥200 mg mLsup?1/sup against tested bacteria. However, the aquatic extract of L. nobili at concentration of 12.5 mg mLsup?1/sup showed the highest antibiofilm activity (86.7%) against S. aureus biofilm formation. The ethanolic extract of M. domestica peels at concentration of 25 mg mLsup?1/sup showed the highest inhibition rate (90%) against P. aeruginosa biofilm formation. Conclusion: These results revealed the importance of the tested extracts in the control of common human pathogenic micro-organisms. Plant extract s used in this study may contain potential antimicrobial and antibiofilm components that may be of great use for the development of new therapies against the most common infectious bacterial isolates.