Preparations are disclosed containing the 3R-3'R stereoisomer of
zeaxanthin as a sole detectable isomer, packaged for oral
ingestion by humans as a therapeutic
drug or nutritional supplement.
Zeaxanthin is a yellow
carotenoid pigment found in the macula (in the center of the human
retina), which helps protect
retinal cells against phototoxic damage. The pure R-R stereoisomer can be prepared by fermenting cells, such as
Flavobacterium multivorum (ATCC 55238), which do not create any detectable quantity of the undesired and potentially toxic S-S or S-R isomers, and which do not synthesize any other carotenoids. The R-R isomer can be concentrated, in large quantities and at low cost, into a viscous oily fluid containing about 5 to 20%
zeaxanthin, by means of a simple
solvent extraction process. This oily fluid can be mixed with a carrier such as
vegetable oil and enclosed within a digestible
capsule, comparable to a conventional
capsule containing
Vitamin E. Alternately, a
zeaxanthin fluid can be added to various types of foods, such as margarine, dairy products, syrup, cookie dough, and certain types of meat preparations which are not subjected to harsh cooking. Additional purification steps can also be used to purify zeaxanthin to a granular or powdered state which contains nearly pure zeaxanthin. Such
processing can be used to create formulations such as ingestible tablets, and particulate formulations that can be added to soups, salads, drinks, or other foods. Preferred stabilizers and anti-oxidants are also disclosed herein. When consumed by humans in any of these
modes, the purified R-R stereoisomer of zeaxanthin can help treat and prevent
macular degeneration, one of the leading causes of
blindness and vision loss, especially among the elderly.