Researchers are taking a look at carnosic acid as possibly having clinical applications for age-related macular degeneration. Carnosic acid is a component of rosemary which is an herb used in kitchens everywhere. Rosemary has antioxidant and anti-inflammatory properties. In previous studies, researchers had determined that carnosic acid fights off free radical damage in the brain and now researchers have found that carnosic acid protects the retina from degeneration and toxicity. In this most recent study, which was published in Investigative Ophthalmology & Visual Science, researchers studied carnosic acid's protective mechanism in retinal cell cultures. The cell cultures were exposed to hydrogen peroxide to induce oxidative stress and then the cells were treated with carnosic acid which initiated antioxidant enzyme production in the cells. This resulted in lowering the levels of cell-damaging free radicals and peroxides. The team then tested carnosic acid in rodents that had light-induced damage to photoreceptors. Rodents that had been pre-treated with carnosic acid had a thicker outer nuclear layer in the eye, which indicated that their photoreceptors were protected. The team is continuing their research and is now creating improved derivatives of carnosic acid to protect the retina and the brain as well from various degenerative conditions including age-related macular degeneration. Larger more well-controlled human studies will be required to determine if this is a viable nutritional therapy for people with macular degeneration.