Effects Of Polyphenols On Intestinal Absorption Of Lutein In Different Digestive Stages

Lutein is a natural carotenoid that is widely present in vegetables,fruits,flowers and certain algal organisms.Lutein has important functions such as antioxidant,protecting eyesight,preventing cataract,preventing diabetes and slowing down early arteriosclerosis.It cannot be synthesized in the body itself and must be ingested or supplemented from the daily diet.Usually,the digestion of lutein is carried out at the same time as other nutrients,and the interaction between the substances has a certain influence on the absorption of lutein.As a natural active substance widely present in vegetables and fruits,polyphenols can not be ignored in the intestinal absorption of lutein,but the mechanism of regulating the intestinal absorption of lutein is rarely explored.In this paper,epigallocatechin(EGC),xanthohumol(XN),anthocyanin(PC),quercetin(QR),hesperetin(HES),gallocatechin gallate(EGCG),Hesperidin(HES-G),curcumin(E100)and lutein were used as the research objects.By constructing in vitro digestion model,intestinal epithelial cell absorption model and mouse model to explore the bioaccessibility of polyphenols to lutein,Intestinal absorption and metabolic effects of in vivo absorption.The research results will provide a new idea for scientific supplementation of lutein,and also provide a theoretical basis for the development of lutein compound healthy food.The main findings of the paper are as follows:(1)The effect of polyphenols on lutein bioaccessibility was investigated by simulated in vitro digestion.The results showed that adding polyphenols could significantly improve the bioaccessibility of lutein,and the bioaccessibility of lutein was increased by 3.3-7 times(P < 0.05).Accessibility is as high as 24.3%.The addition of polyphenols increased lipid digestion in the small intestine catalyzed by lipase,but the effect of different polyphenols was different.After 120 min of digestion,the degree of EGCG lipid hydrolysis was as high as 92.1%.Polyphenols can increase the micellization rate of lutein by 0.89-2.54 times,and EGCG can increase the micellization rate of lutein by 2.54 times(P < 0.05).At the same time,polyphenols can also reduce the average particle size of lutein micelles and increase the absolute value of site to increase the stability of lutein micelles in the gastrointestinal environment.(2)By constructing a Caco-2 cell model,the effect of polyphenols on lutein cell uptake was studied.The results showed that polyphenols increased the cellular absorption of lutein by 3.2%-30.4%,of which EGC had the most significant effect,up to 30.4%(P < 0.05).Polyphenols increased the cellular absorption of lutein by increasing the apparent permeability coefficient of the cell membrane and activating the expression of lutein membrane transporter SR-BI,NPC1L1 and CD36,among which CD36 protein expression increased the most,4.12%-7.64% higher than the control group SR-BI protein was the second,which was 10.4%-139.6% higher than the control group,and NPC1L1 protein was the second,which was 1.25%-79.6%higher than that of the control group.(3)By constructing a mouse model,the effects of polyphenols on the accumulation of lutein and its metabolites and the intestinal flora in mice were studied.The results showed that co-feeding of polyphenols and lutein significantly increased the content of lutein in liver,plasma,small intestine and eyeball of mice.Among them,the accumulation of lutein in the liver increased by 2.36-7.27 times,and the promotion effect of xanthohumol was the most significant;the content of lutein in the plasma increased by 11.1-66.7%,and the effect of xanthohumol was also the most obvious.The polyphenol treatment group significantly increased the expressions of NPC1L1,SR-BI,and CD36,among which CD36 protein increased the most,3.45-5.67 times higher than the control group,followed by SR-BI protein,which was 0.2-3.1 higher than the control group NPC1L1 protein was the worst,which was 0.3-1.9 times higher than that of the control group(P < 0.05).Polyphenols significantly increased the content of lutein metabolites in the liver and small intestine of mice.Except for HES,the total metabolic content of lutein in the liver increased by 0.09-1.66 times;the total metabolic content of lutein in the small intestine increased by 0.43-2.13 times(P <0.05).And significantly improve the α-diversity and β-diversity of intestinal flora,and at the same time increase the relative abundance of intestinal beneficial bacteria,and promote the absorption of lutein in vivo.