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Updated: May 9, 2025
Evaluation of Antimicrobial Activities of Nanoparticles and Nanostructured Surfaces In Vitro
Published on: April 21, 2023
Nano-encapsulated Melissa officinalis Essential Oil and Its Antibacterial Effects Against Multi Drug Resistant E.
Fateme Lotfi1, Mehran Nemattalab1,2, Zahra Hesari3,4
1Department of Pharmaceutics, School of Pharmacy, Guilan University of Medical Sciences, Rasht, Iran.
Abstract:
Urinary tract infections (UTIs) are common bacterial infections in children, frequently caused by E. coli and K. pneumoniae, whose biofilm-forming ability makes them resistant to antibiotics. In order to investigate an alternate drug delivery system to combat the microbial resistance, M. officinalis essential oil with its inherent antimicrobial properties was loaded in solid lipid nanoparticles (SLN) to properly enhance its antibacterial effects. Physico-chemical evaluations along with antibacterial assessment were conducted. Dynamic light scattering (DLS) results revealed that SLNs had an average size of 138.8 ± 34.3 nm and a zeta potential of -32.3 mV. Transmission electron microscopy (TEM) images confirmed their cuboid structure and smooth surface. The encapsulation efficiency of MO-SLN was 83 ± 2.1% and cumulative oil release from MO-SLN was 86.34 ± 0.1 in 72 h. The antibacterial activity of MO-SLN and MO were reported with MIC and MBC values of 545-570 µgmL-1, 1240-1260 µgmL-1 and 365-395 µgmL-1, 925-955 µgmL-1 for MDR E. coli and K. pneumoniae, respectively. Consequently, MO-SLN significantly reduced the MIC compared to pure MO, indicating that SLN as a nanocarrier can significantly increase the antibacterial effects of Melissa officinalis essential oil.
Insights
This study developed Melissa officinalis essential oil-loaded solid lipid nanoparticles (SLN) to enhance antibacterial effects against multidrug-resistant bacteria. MO-SLN significantly improved antimicrobial activity compared to the essential oil alone.
Area of Science:
- Pharmaceutical Science
- Nanotechnology
- Microbiology
Background:
- Urinary tract infections (UTIs) in children are often caused by antibiotic-resistant bacteria like E. coli and K. pneumoniae.
- Biofilm formation by these pathogens contributes to their resistance, necessitating alternative treatment strategies.
Purpose of the Study:
- To develop a novel drug delivery system using solid lipid nanoparticles (SLN) to encapsulate Melissa officinalis (MO) essential oil.
- To evaluate the enhanced antibacterial efficacy of MO-loaded SLN (MO-SLN) against multidrug-resistant (MDR) E. coli and K. pneumoniae.
Main Methods:
- Physico-chemical characterization of MO-SLN using Dynamic Light Scattering (DLS) and Transmission Electron Microscopy (TEM).
- Determination of encapsulation efficiency and cumulative oil release over 72 hours.
- Antibacterial assessment by determining Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) values.
Main Results:
- MO-SLN exhibited a mean particle size of 138.8 nm and a negative zeta potential (-32.3 mV).
- High encapsulation efficiency (83%) and cumulative oil release (86.34% in 72h) were achieved.
- MO-SLN demonstrated significantly lower MIC and MBC values against MDR E. coli and K. pneumoniae compared to pure MO.
Conclusions:
- Solid lipid nanoparticles serve as an effective nanocarrier for Melissa officinalis essential oil.
- MO-SLN significantly enhances the antibacterial activity of MO, offering a promising approach to combat antibiotic-resistant UTIs in children.
