Modulatory Effect of <i>Lippia alba</i> Essential Oil on the Activity of Clinically Used Antimicrobial Agents on <i>Salmonella typhi</i> and <i>Shigella dysenteriae</i> Biofilm

• Main Authors: Andressa Batista (Author), Hilania Dodou (Author), Matheus Rodrigues (Author), Pedro Pereira (Author), Gleilton Sales (Author), Suelen Medeiros (Author), Nádia Nogueira (Author)
• Format: Book
• Published: MDPI AG, 2018-12-01T00:00:00Z.
• Subjects: article
• Online Access: Connect to this object online.

Summary

The essential oil obtained from the leaves of <i>Lippia alba</i> (Mill.) N.E. Brown (<i>Verbenaceae</i>) has shown great pharmacological potential as an analgesic, antispasmodic, and antimicrobial agent. The aim of this study was to evaluate the modulatory effect of <i>Lippia alba</i> essential oil (LaEO I) on the activity of clinically used antimicrobial agents on <i>Salmonella enterica</i> serovar Typhi <i>(Salmonella typhi</i>) and <i>Shigella dysenteriae</i> biofilms. The Minimum Inhibitory Concentration of LaEO I (MIC_{LaEO I}) was determined by the microdilution method, and the effect of LaEO I on the activity of clinically used antimicrobials was assessed by the Checkboard method. The values obtained from MIC_{LaEO I} and ciprofloxacin were used to evaluate the effect of time of exposure on cell viability. LaEO I main components were geranial (34.2%), neral (25.9%), and myrcene (12.5%). The MIC_{LaEO I} was 1 mg/mL for both strains. LaEO I positively modulated the action of ciprofloxacin, cefepime, and ceftriaxone. After the first hour of treatment with MIC_{LaEO I}, the cell viability of the strains showed a 5 log10 CFU/mL reduction, and the LaEO I-CIP association was able to inhibit growth during the first 6 h of the test. Regarding the anti-biofilm activity, MIC_{LaEO I} was able to reduce the biofilm mass of <i>Salmonella typhi</i> by 61.2% and of <i>Shigella dysenteriae</i> by 38.9%. MIC_{LaEO I} was not able to eradicate the preformed biofilm; however, there was a reduction in the biofilm microbial viability. LaEO I has the potential to be used as an antimicrobial agent and interferes with biofilm formation; also, it is able to reduce cell viability in preformed biofilm and synergistically modulate the activity of ciprofloxacin.

Item Description

2218-0532
10.3390/scipharm86040052