1. Chemical structure
The molecular formula of lutein is C40H56O2, the relative molecular weight is 568.85 and CAS No. 127-40-2; lutein is a dihydroxy carotenoid containing an ionone ring.
The molecular formula of lutein ester is C72H116O4, and the relative molecular weight is 1045.71.
Lutein ester is the fatty acid structure of lutein and has a larger molecular weight.
Lutein ester is a carotenoid fatty acid ester. The main structure is composed of two six-membered carbon rings connected by a long chain with a conjugated double bond containing eighteen carbon atoms. Lutein ester can be divided into trans- Formula and cis-lutein esters, most of which exist in natural plants in all-trans molecular configuration.
2. Process
Lutein ester is obtained by extraction with organic solvent from marigold flowers, and then the lutein ester is further saponified with alkali reagents, and the fatty acid structure -R in the lutein ester structure is converted into -OH, which becomes Lutein. Lutein ester is an intermediate product for obtaining lutein, which also indirectly indicates that the naturally occurring component in marigold is lutein ester, not lutein.
3. Source
This form of lutein is not absent in nature. For example, lutein exists in free non-esterified form in green vegetables and fruits, such as broccoli, green beans, green peas, kidney beans, kale, kale, spinach. The lutein present in green vegetables and fruits such as lettuce is free.
Lutein in yellow or orange fruits and vegetables exists in the form of fatty acid esters of lutein such as myristic acid, lauric acid, palmitic acid, etc., such as in mango, papaya, peach, plum (plum), pumpkin, winter squash, oranges, etc., there are a lot of lutein esters, rather than free lutein.
Spectroscopic analysis found that most of the pigment components in marigold flowers exist in the form of esters, which are mainly composed of lutein esters of 8 different fatty acids. The form of fatty acids also makes lutein more stable in marigold.
4. Metabolic process
Lutein and lutein esters are used as raw materials for eye protection. Whether the effect is good or not is related to its availability and metabolism. Lutein naturally exists in the macular area of the human eye and the brain. Modern research has also found that lutein can be directly absorbed and utilized by the body through the human intestine.
Lutein ester has a terminal fatty acid structure, and the molecule is relatively large and cannot be used directly. It needs to be decomposed and converted into free lutein and then absorbed and utilized.
The bioavailability of lutein esters is related to the amount of fat in the diet. Lutein esters usually require esterase or lipase to catalyze hydrolysis, so moderate intake of fat is beneficial for the absorption and utilization of lutein esters.
5. Efficacy
Which eye care effect is better between lutein and lutein ester at the same dose? In fact, this issue is still inconclusive, but we may be able to see the difference in efficacy from the registration of health food.
From January 2000 to February 2022, Zhitiqiao took stock of 161 domestically registered health foods for relieving visual fatigue in the past 22 years, of which 73 used lutein and 4 used lutein esters.
In addition, among the registered products of lutein, 7 health-care functions are in the direction of anti-oxidation, and 4 products are declared to have the effect of enhancing immunity. This may reflect that the efficacy of lutein in eye care health food can be more recognized.
