A group of fat-soluble compounds produced by plants that provide protection from free-radicals as a result of photosynthesis. It is believed that these protective benefits are passed along when these plants are consumed by humans. Some carotenes can be converted into Vitamin A (retinal) such as beta-carotene, alpha-carotene, and gamma-carotene. Other carotenes cannot be converted into Vitamin A but still offer many protective benefits. These include lycopene, zeaxanthin, and lutein.