Photoprotective Carotenoids Lutein and Zeaxanthin: Their Role in AMD

Carotenoids are commonly present exclusively in flora and microbes where they perform critical functions in photosynthesis and photoprotection. These lipophilic molecules are not synthesized by vertebrates and invertebrates. Carotenoids are recognized as high-value antioxidant food supplements and their antioxidant activity may be higher than β-carotene and ??-tocopherol leading to a prevention of lipid peroxidation. In addition, other beneficial effects of carotenoids are well established. These include reduction in gastric inflammation, bacterial load reduction in H-pylori infected humans and mice, age related macular degeneration, prevention of carcinogenesis, atherosclerosis, cardiovascular ailments etc. Epidemiology and clinical studies have shown that each carotenoid has its own individual characteristics. For example β-cryptoxanthin has been shown to be potent in lung cancer and lycopene is inversely associated with prostate cancer and astaxanthin inhibits LDL oxidation. Over 700 natural carotenoids with diverse molecular structures have been identified with potential medical benefits. However, only a handful of carotenoids, such as α-carotene, β- carotene, astaxanthin, β-cryptoxanthin, lycopene, canthaxanthin, lutein and zeaxanthin have been explored for their health benefits. Leutin and zeaxanthin are commonly found in human fluids including macula. This review summarizes role of these two carotenoids in age related macular degeneration.