Lab studies have proven oil of oregano’s capacity to inhibit the growth of, and kill, harmful pathogens. It has the ability to penetrate cell membranes and disrupt their integrity. The increased permeability, or “leaky” quality of the bacterial cell wall causes fluid to seep out, leading to cellular death. This ability to damage bacteria is common to the whole plant, as well as its active constituents, carvacrol and thymol. Oil of oregano also lowers the pH inside the bacteria, creating acidic conditions that inhibit metabolism and reproduction. Oil of oregano also works by boosting levels of white blood cells that fight off infection, such as cytotoxic and helper T-cells.
The anti-inflammatory effects of oil of oregano are due to rosmarinic acid, an active constituent that decreases the number of neutrophils (white blood cells that rush to a site and cause an inflammatory reaction) and eosinophils (white blood cells that produce harmful oxidative substances such as free radicals).
As an antioxidant, oil of oregano increases the activity and concentration of other antioxidants, and protects against cancer by preventing the growth of cancer cells at the DNA level. One of the main causes of coronary heart disease is oxidative damage; oil of oregano helps prevent heart disease by regulating the inappropriate oxidation of LDL (“bad”) cholesterol.