Lutein Lutein Lutein (; from Latin "luteus" meaning "yellow") is a xanthophyll and one of 600 known naturally occurring carotenoids. Lutein is synthesized only by plants and like other xanthophylls is found in high quantities in green leafy vegetables such as spinach, kale and yellow carrots. In green plants, xanthophylls act to modulate light energy and serve as non-photochemical quenching agents to deal with triplet chlorophyll (an excited form of chlorophyll), which is overproduced at very high light levels, during photosynthesis. See xanthophyll cycle for this topic. Lutein is obtained by animals by ingesting plants. In the human retina, lutein is
Photosynthesis Cycle. Nobel Prize-winning scientist Rudolph A. Marcus was able to discover the function and significance of the electron transport chain. Otto Heinrich Warburg and Dean Burk discovered the I-quantum photosynthesis reaction that splits the CO, activated by the respiration. In 1950, first experimental evidence for the existence of photophosphorylation "in vivo" was presented by Otto Kandler using intact "Chlorella" cells and interpreting his findings as light-dependent ATP formation. In 1954, Daniel I. Arnon et al. discovered photophosphorylation "in vitro" in isolated chloroplasts with the help of P. Louis N.M. Duysens and Jan Amesz discovered that chlorophyll a will absorb one