OREGANO OIL - General Discussion

The antimicrobial activity of herbs is concentrated in lipid extracts, known as essential aromatic oils. The antifungal effects of essential oils, including oregano, cloves, garlic, onion, savory and thyme were first reported in 1956. These observations were extended by Belaiche, who described the antimicrobial effects of essential oils of 44 different herbs and spices using an agar diffusion method. That study indicated the oil of oregano effectively inhibited the growth of Candida albicans, as well as several undesirable bacteria. More recently, 32 essential oils were screened for their ability to inhibit food spoilage and industrial yeasts. Oregano was found to be one of the strongest inhibitors.

Oil of oregano contains a variety of terpenoids and phenolic compounds. The phenolic terpenoid, carvacrol, is a major constituent of this oil. Several reports had shown that carvacrol inhibited C. albicans and Pseudomonas aeruginosa and foodborne organisms. We demonstrated that carvacrol inhibited C. albicans as effectively as oil of oregano. Analysis demonstrated that our oil of oregano contained approximately 60% carvacrol and we concluded that the anti-Candida properties of this essential oil are likely due to its content of carvacrol. Other studies demonstrated sensitivity of Staphylococcus aureus, Pseudomonas spp, Proteus mirabilis, Klebsiella pneumonia and group B streptococcus, E coli, Aerobacter aerogluess, and Bacillus subtilis to oregano. Therefore, the data indicate that oil of oregano exhibits a broad spectrum antimicrobial activity. Although the mechanism of action of essential oils is unknown, it has been suggested that essential oils can bind to cell membranes and interfere with microbial membrane function.