Effects of Mixed Micellar Lipids on Carotenoid Uptake by Human Intestinal Caco-2 Cells

Long Short-Term Memory-Based Multiomics Reveal Lactobacillus casei-Derived Postbiotics Inhibiting Lipids Digestion via Mediating the Upregulation of α-Helices in Lipase

SCOPE

The antiobesity function of probiotics has been declared, while the application in high-risk patients and coding side effect has focused attention to postbiotics. This investigation profiles the mechanism of postbiotics affecting lipid digestion at molecular level, and establishes a momentous foundation for the clinical application of postbiotics in obesity suppression.

METHODS AND RESULTS

An operational framework for butter digestion is constructed to collect the digests in the intestine at 0, 40, 80, and 120 min with various postbiotics supplement. A total of 227 lipids and 414 metabolites are detected by pseudo-targeted lipidomics integrated with the long short-term memory-based metabolomics, and the triacylglycerol (TG, from 134.1 to 184.7 mg kg-1 ) and diacylglycerol (DG, from 4.2 to 8.4 mg kg-1 ) are identified as significantly different lipids with or without postbiotics supplement. A total of eight substances related to the inhibition of gastric lipase and pancreatic lipase are screened through the molecular simulation computation in silicon and enzymatic reaction kinetics, and thus curtailing the bioaccessibility of lipids.

CONCLUSIONS

Lactobacillus casei JCM1134-derived postbiotics propel the structure of lipase to aggregate by increasing the α-helix, and thus hampering the digestion of triglycerides through noncompetitive inhibition.

Neoxanthin is undetectable in human blood after ingestion of fresh young spinach leaf

In a previous study, we demonstrated that the carotenoid neoxanthin was contained in young leafy vegetables including spinach and showed a fat accumulation inhibitory effect in vitro. To evaluate the bioavailability of neoxanthin, a raw young spinach leaf (100 g day-1 for 4 weeks) intake test was performed on 14 participants (36.5 ± 8.0 years; male:female ratio = 9:5). Neoxanthin, neochrome, β-carotene, and lutein concentration in the spinach and blood of participants (before and after the test) was measured using high performance liquid chromatography. Neither neoxanthin nor neochrome was detected in the blood samples, whereas β-carotene and lutein concentration significantly increased (1.4- and 1.9-fold, respectively) during testing. Neoxanthin bioavailability in humans is low; thus, it is unlikely to have a fat accumulation inhibitory effect in vivo, contrary to the result in vitro. Ingesting the leafy vegetables raw can help maintain high neoxanthin levels, but it is not beneficial for neoxanthin bioavailability.

Solubilization of α-tocopherol and curcumin by polyoxyethylene alkyl ether surfactants: Effect of alkyl chain structure

The effects of the structural characteristics of the alkyl chains of polyoxyethylene alkyl ether-type surfactants (Brij) on the solubilization of α-tocopherol and curcumin by surfactant micelles were investigated: Brij L23 (lauryl; C_12:0); S20 (stearyl; C_18:0); and Brij O20 (oleyl; C_18:1). When α-tocopherol or curcumin were solubilized in Brij micelle solutions below their maximum solubilization concentrations (C_max), the Brij L23 micelles exhibited the largest increase in dimensions due to the presence of the guest molecules. Above C_max, excess α-tocopherol existed as microemulsion droplets whereas excess curcumin existed as insoluble crystals. Our results suggest that the guest molecules were preferentially located within the palisade layers of micelles, which can be attributed to the fact that they contained bother polar and non-polar moieties. These results may be important for the formulation of colloidal delivery systems to encapsulate and deliver oil-soluble vitamins and nutraceuticals.

Intestinal Absorption and Anti-Inflammatory Effects of Siphonein, a Siphonaxanthin Fatty Acid Ester from Green Algae

Siphonein is a C19 acylated siphonaxanthin found in some edible green algae (e.g., Codium fragile and Caulerpa lentillifera). Although the content of siphonein in these green algae is similar to or higher than that of siphonaxanthin, studies of health-related biological activity of siphonein are much less than those of siphonaxanthin. Given the difference in the position of the acyl chain, one cannot infer intestinal absorption of siphonein from other general carotenoid fatty acid esters. In this study, we first investigated the intestinal absorption of siphonein using mouse and cell culture models. A small amount of siphonein was detected in the plasma of treated mice, and its concentration was higher than that of siphonaxanthin (i.e., the hydrolyzed product of ingested siphonein) from 1 to 6 h after administration. Pharmacological inhibition tests with differentiated Caco-2 cells showed that Nieman-Pick C1-like 1-mediated facilitated diffusion was involved in the cellular uptake of siphonein. These results indicate that, unlike general carotenoid fatty acid esters, siphonein can be absorbed without hydrolysis. We also evaluated the anti-inflammatory effect of siphonein in differentiated Caco-2 cells. Siphonein pretreatment modulated lipopolysaccharide-induced cellular lipidome alterations and suppressed mRNA expression of proinflammatory chemokines, CXCL8 protein release, and activation of NF-κB. This study provides new insights into the absorption processes of carotenoids and shows the anti-inflammatory effect of siphonein for the first time.

Encapsulation of Lutein via Microfluidic Technology: Evaluation of Stability and In Vitro Bioaccessibility

Inadequate intake of lutein is relevant to a higher risk of age-related eye diseases. However, lutein has been barely incorporated into foods efficiently because it is prone to degradation and is poorly bioaccessible in the gastrointestinal tract. Microfluidics, a novel food processing technology that can control fluid flows at the microscale, can enable the efficient encapsulation of bioactive compounds by fabricating suitable delivery structures. Hence, the present study aimed to evaluate the stability and the bioaccessibility of lutein that is encapsulated in a new noodle-like product made via microfluidic technology. Two types of oils (safflower oil (SO) and olive oil (OL)) were selected as a delivery vehicle for lutein, and two customized microfluidic devices (co-flow and combination-flow) were used. Lutein encapsulation was created by the following: (i) co-flow + SO, (ii) co-flow + OL, (iii) combination-flow + SO, and (iv) combination-flow + OL. The initial encapsulation of lutein in the noodle-like product was achieved at 86.0 ± 2.7%. Although lutein’s stability experienced a decreasing trend, the retention of lutein was maintained above 60% for up to seven days of storage. The two types of device did not result in a difference in lutein bioaccessibility (co-flow: 3.1 ± 0.5%; combination-flow: 3.6 ± 0.6%) and SO and OL also showed no difference in lutein bioaccessibility (SO: 3.4 ± 0.8%; OL: 3.3 ± 0.4%). These results suggest that the types of oil and device do not affect the lutein bioaccessibility. Findings from this study may provide scientific insights into emulsion-based delivery systems that employ microfluidics for the encapsulation of bioactive compounds into foods.

Uptake of Vitamins D2, D3, D4, D5, D6, and D7 Solubilized in Mixed Micelles by Human Intestinal Cells, Caco-2, an Enhancing Effect of Lysophosphatidylcholine on the Cellular Uptake, and Estimation of Vitamins D' Biological Activities

Vitamins D have various biological activities, as well as intestinal calcium absorption. There has been recent concern about insufficient vitamin D intake. In addition to vitamins D₂ and D₃, there are lesser-known vitamins D₄–D₇. We synthesized vitamins D₅–D₇, which are not commercially available, and then evaluated and compared the mixed micelles-solubilized vitamins D uptake by Caco-2 cells. Except for vitamin D₅, the uptake amounts of vitamins D₄–D₇ by differentiated Caco-2 cells were similar to those of vitamins D₂ and D₃. The facilitative diffusion rate in the ezetimibe inhibited pathway was approximately 20% for each vitamin D type, suggesting that they would pass through the pathway at a similar rate. Lysophosphatidylcholine enhanced each vitamin D uptake by approximately 2.5-fold. Lysophosphatidylcholine showed an enhancing effect on vitamin D uptake by reducing the intercellular barrier formation of Caco-2 cells by reducing cellular cholesterol, suggesting that increasing the uptakes of vitamins D and/or co-ingesting them with lysophosphatidylcholine, would improve vitamin D insufficiency. The various biological activities in the activated form of vitamins D₄–D₇ were estimated by Prediction of Activity Spectra for Substances (PASS) online simulation. These may have some biological activities, supporting the potential as nutritional components.

Influence of nutrients on the bioaccessibility and transepithelial transport of polybrominated diphenyl ethers measured using an in vitro method and Caco-2 cell monolayers

Previous research has shown the absorption of polybrominated diphenyl ethers (PBDEs) in the human gastrointestinal tract, but limited attention has been given to the influence of nutrients on PBDE absorption from food matrices. We investigated the effects of nutrients (oil, starch, protein, and dietary fiber) on the absorption and transport of PBDEs in a Caco-2 cell model and bioaccessibility of PBDEs by an in vitro gastrointestinal digestion method. The results showed that the accumulation ratios of PBDE congeners in Caco-2 cells were higher in the nutrient addition groups (oil: 26.7-50.6%, starch: 27.0-58.7%, protein: 12.1-44.1%, and dietary fiber: 28.2-55.1%) than the control group (7.17-36.1%), whereas the transport ratios were lower (oil: 2.30-7.20%, starch: 1.55-9.15%, protein: 1.04-8.78%, and dietary fiber: 0.85-7.04%) than control group (3.78-11.1%). Additionally, the PBDE bioaccessibility could be increased by adding the nutrients, particularly oil and starch. This study clarified the differences in PBDE absorption in the presence of nutrients using the in vitro digestion and Caco-2 cell model. The findings showed that nutrients were an important factor that promoted PBDE absorption in the gastrointestinal tract. Therefore, it is important to focus on a novel dietary strategy of food consumption with contaminant compounds to protect human health.

Effect of dispersed form on the bioavailability of β-carotene from daily intake in humans

In a randomized double-blind crossover study, a canned beverage was prepared using an emulsion dispersion formulation (EM) of β-carotene and a crystal dispersion formulation (CR) of β-carotene; the beverages were ingested by human subjects daily for 2 weeks to compare the β-carotene bioavailability. EM-β-carotene enhanced the β-carotene concentrations in human plasma approximately 4-fold, but CR-β-carotene showed no statistically significant enhancement. Bioaccessibility is the ratio of the solubilized fraction to the whole amount ingested. Bioaccessibility of β-carotene from EM-β-carotene was higher than that from CR-β-carotene in an in vitro digestion test. Contrarily, β-carotene from CR-β-carotene, consists of all-trans-β-carotene, was higher than that from EM-β-carotene, consists of a mixture of cis and all-trans-β-carotene, on the uptake by intestinal Caco-2 cells, suggesting that bioaccessibility was a critical factor in β-carotene bioavailability in this study. EM-β-carotene thus has potential as a food coloring agent with value added because it enhances β-carotene bioavailability.

Reduction in the Radiocesium in Meats of the Sika Deer and Wild Boar by Cooking

ABSTRACT

The behavior of radiocesium in wild animal meats upon cooking was investigated. The ratio of the concentration change (processing factor, Pf), remaining ratio (food processing retention factor, Fr), and removal ratio of radiocesium in the meats by grilling, boiling, and steaming were determined. Differences in cooking methods, rather than differences in meat parts or animal species, clearly influenced the Pf, Fr, and removal ratios. The mean Fr values were 0.9 (range, 0.7 to 1.0) for grilling, 0.6 (range, 0.4 to 0.7) for boiling, and 0.5 (range, 0.4 to 0.7) for steaming. The removal effect of grilling (11%) was lower than that of boiling (41%) or steaming (47%). The mean value of Pf was 1.2 (range, 1.1 to 1.6) for grilling, 0.8 (range, 0.6 to 0.9) for boiling, and 0.8 (range, 0.7 to 1.0) for steaming. The radiocesium concentration in the meats increased only upon grilling, but not by boiling or steaming. This difference is due to the lower removal effect of grilling than that of boiling and steaming. Therefore, boiling and steaming were more effective than grilling for removing radiocesium and reducing its concentration in wild animal meats. Furthermore, the ratio of water content fluctuations due to boiling was negatively correlated with Pf and Fr. It was evident that greater reductions in water content resulted in lower concentrations and improved radiocesium removal in the meats. These results suggest that some of the radiocesium naturally present in the meats is soluble in water and that the radiocesium dissolved in water can be removed from the meat with the release of water from the tissue.

HIGHLIGHTS

Niemann-Pick C1-like 1 Promotes Intestinal Absorption of Siphonaxanthin

Siphonaxanthin is a carotenoid found in certain green algae, and its promising beneficial properties, such as its anti-obesity effect, have recently been demonstrated. However, there is little information about the molecular mechanisms underlying intestinal absorption of siphonaxanthin. In this study, we aimed to elucidate how siphonaxanthin is transported across the intestinal epithelium using differentiated Caco-2 cells (dCaco-2 cells), recombinant proteins, and an animal model. Siphonaxanthin was taken up by dCaco-2 cells, a model of intestinal epithelial cells, and its uptake linearly increased up to at least 6 h. Pharmacological inhibition of Nieman-Pick C1-like 1 (NPC1L1), but not that of scavenger receptor class B type 1 (SR-B1), significantly suppressed siphonaxanthin uptake by dCaco-2 cells. Results from an in vitro binding assay suggested that the N-terminal domain of NPC1L1, which is an extracellular domain of NPC1L1, binds with siphonaxanthin. Moreover, pretreatment with ezetimibe, an inhibitor of NPC1L1, significantly decreased the plasma level of siphonaxanthin following oral administration in mice. Considered together, we concluded that NPC1L1 promotes siphonaxanthin transport across the intestinal epithelium.

Hesperetin and Hesperidin Improved β-Carotene Incorporation Efficiency, Intestinal Cell Uptake, and Retinoid Concentrations in Tissues

Dietary constituents can influence the bioavailability of carotenoids. This study investigated the effect of citrus flavanones on β-carotene (Bc) bioavailability using four experimental models: in vitro digestion procedure, synthetic mixed micelles, Caco-2 cell monolayers, and gavage experiments in mice. The addition of hesperetin (Hes, 25 μM) and hesperidin (Hes-G, 25 μM) standards significantly increased the incorporation efficiency of the Bc standard to 68.7 ± 3.6 and 75.2 ± 7.5% ( p < 0.05), respectively. However, the addition of naringenin (Nar, 25 μM) and naringin (Nar-G, 25 μM) standards significantly reduced the incorporation efficiency of Bc by 23.8 and 26.4%, respectively ( p < 0.05). The increases in scavenger receptor class B type I (SR-BI) expression promoted by citrus flavanones played an important role in Bc cellular absorption in the Caco-2 cell model. Furthermore, after 3 days of gavage, four citrus flavanones (7.5 mg kg^-1 day^-1) increased the retinoid concentrations in tissues; in contrast, after 7 days of gavage, Nar and Nar-G significantly decreased hepatic retinoid concentrations ( p < 0.05). This finding suggested that the incorporation efficiency into micelles was the main step governing carotenoid bioavailability.

Polyarginine nanocapsules: A versatile nanocarrier with potential in transmucosal drug delivery

The objective of this work was to investigate the potential utility of nanocapsules composed of an oily core decorated with a single polyarginine (PARG), or double PARG/polyacrylic acid (PAA) layer as oral peptide delivery carrier. A step-by-step formulation optimization process was designed, which involved the study of the influence of the surfactants, oils and polymer shells (PARG of different molecular weight and PAA) on the nanocapsules physicochemical properties, peptide loading efficiency, stability in simulated intestinal fluids (SIF) and capacity to enhance the permeability of the intestinal epithelium. Despite the lipophilic nature of the nanocapsules, it was possible to achieve a moderate loading of the hydrophilic model peptide salmon calcitonin and control its release in SIF, by adjusting the formulation conditions. Finally, studies in the Caco-2 epithelial cell line showed the capacity of the nanocapsules to reduce the transepithelial electric resistance of the monolayer, without compromising their viability. Overall, these properties suggest the capacity of polyarginine nanocapsules for enhancing the transport of peptides across epithelia.

Formulation and Physicochemical Characterization of Lycopene-Loaded Solid Lipid Nanoparticles

PURPOSE

Lycopene belongs to the carotenoids that shows good pharmacological properties including antioxidant, anti-inflammatory and anticancer. However, as a result of very low aqueous solubility, it has a limited systemic absorption, following oral administration.

METHODS

Here, we prepared a stable lycopene-loaded solid lipid nanoparticles using Precirol® ATO5, Compritol 888 ATO and myristic acid by hot homogenization method with some modification. The size and morphological characteristics of nanoparticles were evaluated using Scanning Electron Microscopy (SEM). Moreover, zeta potential and dispersity index (DI) were measured using zeta sizer. In addition, encapsulation efficiency (EE%), drug loading (DL) and cumulative drug release were quantified.

RESULTS

The results showed that the size and DI of particles was generally smaller in the case of SLNs prepared with precirol when compared to SLNs prepared with compritol. Scanning electron microscopy (SEM) and particle size analyses showed spherical SLNs (125 ± 3.89 nm), monodispersed distribution, and zeta potential of -10.06 ± 0.08 mV. High EE (98.4 ± 0.5 %) and DL (44.8 ± 0.46 mg/g) were achieved in the case of nanoparticles prepared by precirol. The stability study of the lycopene-SLNs in aqueous medium (4 °C) was showed that after 2 months there is no significant differences seen in size and DI compared with the fresh formulation.

CONCLUSION

Conclusively, in this investigation we prepared a stable lycopene-SLNs with good physicochemical characteristic which candidate it for the future in vivo trials in nutraceutical industries.

Lysoglyceroglycolipids Improve the Intestinal Absorption of Micellar Fucoxanthin by Caco-2 Cells

To improve the intestinal absorption of fucoxanthin, we evaluated the effects of dietary glyceroglycolipids on the uptake and secretion of fucoxanthin solubilized in mixed micelles by human intestinal Caco-2 cells. Although digalactosyldiacylglycerol and sulfoquinovosyldiacylglycerol suppressed fucoxanthin uptake and secretion, their lyso-types, digalactosylmonoacylglycerol and sulfoquinovosylmonoa cylglycerol, remarkably enhanced them. Thus, some dietary glyceroglycolipids may be potential enhancers of fucoxanthin bioavailability in humans.

Dietary Components Affect the Plasma and Tissue Levels of Lutein in Aged Rats with Lutein Deficiency--A Repeated Gavage and Dietary Study

The aim of this study was to find out the influence of selected dietary components on plasma and tissue response of repeated micellar and dietary lutein in aged rats with lutein deficiency. In repeated (16 d) gavage study, micellar lutein was co-ingested with either phosphatidylcholine (PC), lyso-phosphatidylcholine (lysoPC), β-carotene, dietary fiber or vegetable fat (3% soybean oil). In dietary study, rats were fed (4 wk) semi-synthetic diet either with lutein + PC, lutein + dietary fiber or B. alba (lutein source) + PC. The post-prandial plasma and tissue response of lutein was measured by HPLC. Results showed that micellar fat, PC and lysoPC significantly (P ≤ 0.05) increased the lutein levels in plasma (31.1%, 26.8%, and 34.9%), liver (27.4%, 29.5%, and 8.6%), and eyes (63.5%, 90.2%, and 86%) compared to the control group (group gavaged micelles with no dietary components studied). Similarly, dietary study showed an enhanced plasma, liver, and eye lutein levels by 44.8%, 24.1%, and 42.0% (lutein + PC group) and 51.7%, 39.8%, and 31.7% (B.alba + PC group), respectively compared to control. The activity of antioxidant enzymes in plasma and liver of both the studies were also affected compared to control. Result reveals, that PC enhance the intestinal absorption of both micellar and dietary lutein which is either in free or bound form with food matrices in aged rats with lutein deficiency. Hence, PC at a concentration used in this study can be considered to improve the lutein bioavailability in lutein deficiency.

PRACTICAL APPLICATION

Lutein and zeaxanthin are macular pigments acquired mostly from greens, that play an significant role in protecting vision from Age related macular degeneration (AMD). However, their biological availability is poor and affected by dietary components. This study demonstrates the positive influence of dietary PC and lyso PC in improving intestinal uptake of lutein. Our previous and present finding shows there is a possibility of developing functional/supplemental foods with PC and lyso PC targeted to elderly populace thus minimizing or delaying the vision complication associated like AMD.

Fucoxanthin Derivatives: Synthesis and their Chemical Properties

Novel fucoxanthin derivatives that could change the size of mixed micelles were synthesized. The mixed micelles under consideration consist of a bile acid and some additives. To change the affinity against a bile acid, we designed the synthesis of a fucoxanthin-lithocholic acid complex. Lithocholic acid is one of the bile acids. The 3-OH on lithocholic acid was protected by a levulinyl group, and the protected lithocholic acid was selectively coupled via an ester linkage to the 3-OH on fucoxanthin to obtain levulinyl-protected lithocholyl fucoxanthin (LevLF). The levulinyl group was then selectively deprotected using hydrazine to obtain a lithocholyl fucoxanthin (LF). The average sizes of the micelles that contained these compounds (fucoxanthin, LevLF, and LF) with a bile acid (sodium taurocholate) were measured. The LevLF induced larger micelles than fucoxanthin or LF. Interestingly, the addition of 1-oleoyl-rac-glycerol induced a more efficient change in the micelle size. The large micelles grew larger, and the small micelles became smaller. Triple-mixed micelles with LevLF, sodium taurocholate, and 1-oleoyl-rac-glycerol formed the largest micelle with a diameter of 68 nm. On the other hand, triple-mixed micelles using LF, sodium taurocholate, and 1-oleoyl-rac-glycerol made the smallest micelles with diameters as low as 12 nm. We also investigated the hydrolysis of these compounds with enzymes (esterase from porcine liver, lipase from porcine pancreas, and cholesterol esterase from Pseudomonas sp.). The ester linkage between the lithocholic acid and fucoxanthin of LevLF was hydrolyzed with cholesterol esterase. In addition, the intestinal absorption was examined with Caco-2 cells, and no advantageous change in absorption efficiency was observed by chemically modifying the fucoxanthin unless different micelles sizes and increasing hydrophobicity are induced.

Glyceroglycolipids Affect Uptake of Carotenoids Solubilized in Mixed Micelles by Human Intestinal Caco-2 Cells

We previously reported that phospholipids markedly affected the uptake of carotenoids solubilized in mixed micelles by human intestinal Caco-2 cells. In the present study, we found that two classes of dietary glyceroglycolipids and the corresponding lysoglyceroglycolipids affected uptake of β-carotene and lutein by differentiated Caco-2 cells. The levels of carotenoid uptake from micelles containing digalactosyldiacylglycerol or sulfoquinovosyldiacylglycerol were significantly lower than that from control micelles. On the other hand, the uptakes from micelles containing digalactosylmonoacylglycerol or sulfoquinovosylmonoacylglycerol were significantly higher than that from control micelles. In dispersed cells and Caco-2 cells with poor cell-to-cell adhesion, however, the levels of uptake from micelles containing these lyso-lipids were much lower than that from control micelles. The uptake levels from control micelles were markedly decreased depending on the development of cell-to-cell/cell-matrix adhesion in Caco-2 cells, but the uptake levels from the micelles containing these lyso-lipids were not substantially changed, suggesting that the intercellular barrier formed by cell-to-cell/cell-matrix adhesion inhibited the uptake from control micelles, but not from the lyso-lipid-containing micelles. The lyso-lipids appeared to enhance carotenoid uptake by decreasing the intercellular barrier integrity. The results showed that some types of glyceroglycolipids have the potential to modify the intestinal uptake of carotenoids.

A 3-hydroxy β-end group in xanthophylls is preferentially oxidized to a 3-oxo ε-end group in mammals

We previously found that mice fed lutein accumulated its oxidative metabolites (3'-hydroxy-ε,ε-caroten-3-one and ε,ε-carotene-3,3'-dione) as major carotenoids, suggesting that mammals can convert xanthophylls to keto-carotenoids by the oxidation of hydroxyl groups. Here we elucidated the metabolic activities of mouse liver for several xanthophylls. When lutein was incubated with liver postmitochondrial fraction in the presence of NAD(+), (3'R,6'R)-3'-hydroxy-β,ε-caroten-3-one and (6RS,3'R,6'R)-3'-hydroxy-ε,ε-caroten-3-one were produced as major oxidation products. The former accumulated only at the early stage and was assumed to be an intermediate, followed by isomerization to the latter. The configuration at the C3' and C6' of the ε-end group in lutein was retained in the two oxidation products. These results indicate that the 3-hydroxy β-end group in lutein was preferentially oxidized to a 3-oxo ε-end group via a 3-oxo β-end group. Other xanthophylls such as β-cryptoxanthin and zeaxanthin, which have a 3-hydroxy β-end group, were also oxidized in the same manner as lutein. These keto-carotenoids, derived from dietary xanthophylls, were confirmed to be present in plasma of normal human subjects, and β,ε-caroten-3'-one was significantly increased by the ingestion of β-cryptoxanthin. Thus, humans as well as mice have oxidative activity to convert the 3-hydroxy β-end group of xanthophylls to a 3-oxo ε-end group.

Unsaturated fatty acids promote bioaccessibility and basolateral secretion of carotenoids and α-tocopherol by Caco-2 cells

Bioavailability of carotenoids and tocopherols from foods is determined by the efficiency of transfer from food/meal to mixed micelles during digestion, incorporation into chylomicrons for trans-epithelial transport to lymphatic/blood system, and distribution to target tissues.