Effects of Essential Oils and Monolaurin onStaphylococcus aureus:In VitroandIn VivoStudies

Abstract

The antimicrobial properties of volatile aromatic oils and medium-chain fatty acids derived from edible plants have been recognized since antiquity. To give examples, Origanum oil, used as a food-flavoring agent, possesses a broad spectrum of antimicrobial activity due, at least in part, to its high content of phenolic derivatives such as carvacrol and thymol. Similarly, lauric acid, present in heavy concentrations in coconuts, forms monolaurin in the body that can inhibit the growth of pathogenic microbes. Using Staphylococcus aureus in broth cultures and a microdilution method, comparative efficacy of Origanum oil, and a constituent carvacrol, other essential oils and monolaurin were examined. Origanum oil was the most potent of the essential oils tested and proved bactericidal in culture to two strains of Staphylococcus aureus (ATCC #14154 and #14775) at 0.25 mg/mL. In vitro, monolaurin's effects mirrored Origanum oil. The combination of both was bactericidal at the 0.125 mg/mL concentration of each. In two separate In vivo experiments, injected Staphylococcus aureus (ATCC #14775) killed all 14 untreated mice within a 1-week period. In treated mice, over one third survived for 30 days when given oral Origanum oil daily for 30 days (6/14). Fifty percent of the mice survived for 30 days when receiving daily vancomycin (7/14) and monolaurin (4/8). Over 60% of mice survived when receiving a daily combination of Origanum oil and monolaurin (5/8). Origanum oil and/or monolaurin may prove to be useful antimicrobial agents for prevention and therapy of Staphylococcus aureus infections.

Antimicrobial Activity of Carvacrol: Current Progress and Future Prospectives

“…Preuss et al carried out experiments to test the antimicrobial activity of carvacrol bearing essential oils for the therapy of S. aureus infections [71]. Kristinsson et al [72] showed that the vapors of Ocimum basilicum essential oil and its components (carvacrol, thymol, salicylaldehyde) placed in the ear canal of rats with experimental acute otits media caused by pneumococci or Hemophilus influenza, can effectively treat this pathology.…”

Evaluation of the antimicrobial and antioxidant activities of essential oils, extracts and their main components from oregano from Madeira Island, Portugal

“…Origanum oil, used as food-flavouring agent, possesses a broad spectrum of antimicrobial activity due, at least in part, to its high content of phenolic derivatives, such as carvacrol and thymol (Preuss et al, 2005) In the literature, there are many reports relating the chemical composition and the antimicrobial properties of the essential oils of various origanum species, and their application in various commercial preparations, as antimicrobials and antioxidants (Baydar, Sagdic, Ozkan, & Karadogan, 2004;Kulisic, Radonic, Katalinic, & Milos, 2004).…”

Synergistic interactions between antimicrobial peptides derived from plectasin and lipid nanocapsules containing monolaurin as a cosurfactant against <em>Staphylococcus aureus</em>

“…15 Glycerol monolaurate is generally recognized as safe for human use by Food and Drug Administration, and this compound is commonly used in the cosmetic and food industries. 16,17 Unlike most antibiotics that have single targets for antibacterial activity, monolaurin appears to target nonspecifically many signal transduction systems present at bacterial surface through interactions with plasma membranes.…”