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

Abstract

Background and Objective:Biofilm is a complex microbial community highly resistant to antimicrobials agents. The formation of biofilmsin biotic and abiotic surfaces is associated with high rates of morbidity and mortality and considered as a major factor of bacterialpathogenicity. 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 plants were prepared using microwaveassisted method by ethanol and water. Results: The results of this study revealed that, the aquatic extract of M. domestica peels showedpowerful antimicrobial activity against E. coli with MIC value 1.56 mg mLG1, the ethanolic extract of G. glabra roots showed goodantimicrobial activity against P. aeruginosa with minimum inhibitory concentration (MIC) of 12.5 mg mLG1. Most plant extracts in thisstudy gave the minimum bactericidal concentration (MBC) ≥200 mg mLG1 against tested bacteria. However, the aquatic extract of L. nobiliat concentration of 12.5 mg mLG1 showed the highest antibiofilm activity (86.7%) against S. aureus biofilm formation. The ethanolicextract of M. domestica peels at concentration of 25 mg mLG1 showed the highest inhibition rate (90%) against P. aeruginosa biofilmformation. Conclusion: These results revealed the importance of the tested extracts in the control of common human pathogenicmicro-organisms. Plant extracts used in this study may contain potential antimicrobial and antibiofilm components that may be of greatuse for the development of new therapies against the most common infectious bacterial isolates.