Potential Anti-Infectious Activity of Essential Oil Chemotypes of Lippia origanoides Kunth on Antibiotic-Resistant...

Area of Science:

• Phytochemistry
• Microbiology
• Natural Product Chemistry

Background:

• Staphylococcus aureus infections, including methicillin-resistant strains (MRSA), pose a significant public health threat due to biofilm formation and antibiotic resistance.
• The limited efficacy of current antibiotics necessitates the exploration of novel therapeutic strategies targeting virulence factors and resistance mechanisms.
• Medicinal aromatic plants offer a promising avenue for discovering new antimicrobial agents.

Purpose of the Study:

• To evaluate the antimicrobial, antibiofilm, and antihemolysis properties of three Lippia origanoides essential oil (EO) chemotypes against susceptible and resistant S. aureus strains.
• To characterize the chemical composition of the L. origanoides EOs.

Main Methods:

• Gas Chromatography-Mass Spectrometry (GC-MS) was used for EO chemical composition analysis.
• Minimum Inhibitory Concentration (MIC) assays determined antimicrobial activity.
• Biofilm inhibition assays and antihemolysis assays were conducted to assess virulence factor inhibition.

Main Results:

• Two phenolic chemotypes, rich in carvacrol and thymol, exhibited potent antimicrobial activity (MIC 62.5–500 µg/mL) and inhibited biofilm formation in S. aureus strains.
• The sesquiterpene-rich chemotype (β-caryophyllene) demonstrated novel anti-S. aureus activity (MIC 125–500 µg/mL) and moderate biofilm inhibition.
• Phenolic chemotypes displayed significant antihemolysis activity (IC50 58.9–128.3 µg/mL).

Conclusions:

• Lippia origanoides essential oil, particularly its phenolic chemotypes, possesses significant potential as a source for developing novel anti-S. aureus agents.
• The study highlights the importance of chemotype variation in L. origanoides for therapeutic applications against S. aureus infections.