Preliminary Study On The Metabolism In Vivo And Affect On Light-induced Retina Damage Of Lutein In Rats

Lutein is one of carotenoids with the formula of C₄₀H₅₆O₂ and the molecular weight of 568.88.It exhibited several health-care functions in vivo.Data from various studies suggested that the supplement of lutein was able to reduce the risk of retina diseases such as macular degeneration.Lutein can not be synthesized in animals but comes from food chain and deposited in vivo.Lutein was obtained by the saponification of marigold extracts.With C₁₈-HPLC-PDA,the amount of prepared lutein was assessed,under following conditions:column:Diamonsil^TM C₁₈(4.6mm×250mm,5μm);mobile phase A:CH₃CN-H₂O(9:1,V/V);mobile phase B:ethyl acetate;linear gradient:increased B from 0 to 100% (V/V) in 15 minutes;flow rate:1.0mL/min;monitoring wavelength:450mm;detection wavelength range: 260nm-700nm;Injection volume:20μL.Additionally,with C₃₀-HPLC-PDA,the geometrical isomers of lutein were separated and identified,under following HPLC conditions:with YMC^TM Carotenoid S-5 column(250×4.6mm),mobile phase A and B were acetonitrile-methanoi(75:25,V/V) and MTBE,respectively.Linear gradient elution was performed at the flow rate of 1.0 mL/min with an increased B from 0 to 55%(V/V) in 20 minutes.The PDA acquired the spectra of fractions from 300nm to 600nm with the chromatogram monitoring wavelength of 450nm.Sample injection volume was 20μL.A preliminary investigation into the digestion,absorption of lutein in rats.Rats were fed with lutein and its esters,respectively,by a single gastric administration.The carotenoid compositions of excretion and serum blood were then assessed.Data from those assessment suggested that lutein esters were hydrolyzed during its digestion and absorption and only lutein monomer could be introduced into serum.Additionally,the relative bioavailability of lutein ester was 18.55%in refer to free lutein.The observation is going to be referred by the formulation study of lutein functional food in China.A preliminary study on the role of lutein in light-induced rats' retina damage.After variations in exposure density and time,a light-induced retina damage model was established in rats.LED source was selected with the exposure density of 1000±100 Lux to damage rats' retina for 3 hours.By HE staining,the effect of retina damage was morphologically observed after 15-day lutein uptake.Meanwhile,HPLC on retina extract assessment suggested that no lutein molecule was found iafter 6-day gastric administration.Additionally,a reduction of something similar with(Z)9-Octadecenamide(ODA)was seen.A most significant observation in this study was that the longer time lutein uptake was undertaken,the more serious retina damage took place. Hence,an interesting hypothesis would be deduced:although the whole molecule of lutein did not reach the retina of rat,it could enhance the damage of retina.This hypothesis shows an obvious importance on the mechanism study on lutein in light-induced retina damage.