RESUMEN
Pathways for xanthophyll metabolism have been proposed on the basis of several oxidation products of dietary xanthophylls detected in the tissues of fish, birds, and human subjects. No enzyme reaction had been characterized as responsible for the pathways until a mouse liver homogenate was found to oxidize the 3-hydroxy ß-end of xanthophylls to a 3-oxo ε-end in the presence of a cofactor, NAD+. This oxidation consists of dehydrogenation to an unstable intermediate having a 3-oxo ß-end group and the subsequent migration of a double bond. ß,ε-Caroten-3'-one, a metabolite of ß-cryptoxanthin, was found in human plasma, indicating that the same oxidative activity as that found in the mouse liver works in human tissues.The oxidative cleavage of carotenoids is mediated by two dioxygenases: a central cleavage enzyme and an asymmetric cleavage enzyme. In mice, the latter enzyme was suggested to eliminate carotenoids in tissues, while in humans, this enzyme is inactivated, resulting in carotenoid accumulation. In this chapter, carotenoid metabolism in mammals is described in terms of the oxidation of functional groups and cleavage of the carbon skeleton.
Asunto(s)
Carotenoides , Luteína , Animales , Mamíferos , Ratones , Xantófilas , ZeaxantinasRESUMEN
An oxidative metabolite of lutein, 3'-hydroxy-ε,ε-caroten-3-one, inhibited the differentiation of 3T3-L1 cells to adipocytes and the subsequent triacylglycerol production, but lutein did not. The α,ß-unsaturated carbonyl structure of 3'-hydroxy-ε,ε-caroten-3-one was considered to participate in the inhibitory effect, suggesting that this lutein metabolite has the potential to prevent metabolic syndrome.
Asunto(s)
Adipocitos/citología , Diferenciación Celular/efectos de los fármacos , Luteína/análogos & derivados , Células 3T3-L1 , Animales , Cromatografía Líquida de Alta Presión , Luteína/farmacología , RatonesRESUMEN
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.
Asunto(s)
Glucolípidos/farmacología , Absorción Intestinal/efectos de los fármacos , Xantófilas/metabolismo , Disponibilidad Biológica , Células CACO-2 , Suplementos Dietéticos , Humanos , Micelas , Solubilidad , Xantófilas/químicaRESUMEN
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 ß-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.
Asunto(s)
Glucolípidos/metabolismo , Luteína/metabolismo , beta Caroteno/metabolismo , Células CACO-2 , Humanos , Liposomas/metabolismo , MicelasRESUMEN
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-ß,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 ß-end group in lutein was preferentially oxidized to a 3-oxo ε-end group via a 3-oxo ß-end group. Other xanthophylls such as ß-cryptoxanthin and zeaxanthin, which have a 3-hydroxy ß-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 ß,ε-caroten-3'-one was significantly increased by the ingestion of ß-cryptoxanthin. Thus, humans as well as mice have oxidative activity to convert the 3-hydroxy ß-end group of xanthophylls to a 3-oxo ε-end group.
Asunto(s)
Xantófilas/metabolismo , Animales , Carotenoides/química , Carotenoides/metabolismo , Criptoxantinas/química , Criptoxantinas/metabolismo , Humanos , Hígado/metabolismo , Luteína/análogos & derivados , Luteína/química , Luteína/metabolismo , Masculino , Mamíferos , Ratones Endogámicos ICR , Oxidación-Reducción , Xantófilas/química , Zeaxantinas/química , Zeaxantinas/metabolismoRESUMEN
The low bioavailability of lipophilic micronutrients is mainly caused by their limited solubilization to an aqueous micelle, which hinders their ability to be taken up by the intestines. Bioaccessibility is the ratio of the solubilized portion to the whole amount ingested. We evaluated in this study the effects of individual fats and oils and their constituents on the bioaccessibility of carotenoids and vitamin E in vegetables by simulated digestion. Various fats and oils and long-chain triacylglycerols enhanced the bioaccessibility of ß-carotene present in spinach, but not of lutein and α-tocopherol, which are less hydrophobic than ß-carotene. Free fatty acid, monoacylglycerol, and diacylglycerol also enhanced the bioaccessibility of ß-carotene present in spinach. In addition to the long-chain triacylglycerols, their hydrolyzates formed during digestion would facilitate the dispersion and solubilization of ß-carotene into mixed micelles. Dietary fats and oils would therefore enhance the bioaccessibility of hydrophobic carotenes present in vegetables.
Asunto(s)
Carotenoides/farmacocinética , Grasas Insaturadas en la Dieta/farmacología , Verduras/química , Vitamina E/farmacocinética , Disponibilidad Biológica , Ácidos Grasos/farmacología , Humanos , Luteína/farmacocinética , Triglicéridos/farmacología , alfa-Tocoferol/farmacocinéticaRESUMEN
We reported previously that lysophosphatidylcholine remarkably enhanced ß-carotene uptake from bile acid-mixed micelles by human intestinal Caco-2 cells. In the present study, we evaluated how mixed micelle components other than phospholipids, viz., fatty acids, monoolein, and cholesterol, affect carotenoid uptake by Caco-2 cells. Each component influenced the ß-carotene uptake in a different way depending on micellar composition. Oleic acid at 200 µM significantly enhanced uptake in the absence of lysophosphatidylcholine. Cholesterol at 40 µM significantly reduced uptake in the presence of lysophosphatidylcholine, while no reduction was found in the presence of 200 µM oleic acid. Facilitated diffusion was suggested partly to mediate uptake in mixed micelles, except for mixed micelles containing 200 µM oleic acid. Uptake mediated by facilitated diffusion was approximately 20% of total uptake. Mixed micellar lipids have the potential to modify intestinal uptake.
Asunto(s)
Colesterol/farmacología , Lisofosfatidilcolinas/farmacología , Ácido Oléico/farmacología , beta Caroteno/metabolismo , Ácidos y Sales Biliares/química , Células CACO-2 , Cromatografía Líquida de Alta Presión , Difusión Facilitada , Humanos , Micelas , beta Caroteno/agonistas , beta Caroteno/antagonistas & inhibidoresRESUMEN
Dietary carotenoids, especially xanthophylls, have attracted significant attention because of their characteristic biological activities, including anti-allergic, anti-cancer, and anti-obese actions. Although no less than forty carotenoids are ingested under usual dietary habits, only six carotenoids and their metabolites have been found in human tissues, suggesting selectivity in the intestinal absorption of carotenoids. Recently, facilitated diffusion in addition to simple diffusion has been reported to mediate the intestinal absorption of carotenoids in mammals. The selective absorption of carotenoids may be caused by uptake to the intestinal epithelia by the facilitated diffusion and an unknown excretion to intestinal lumen. It is well known that ß-carotene can be metabolized to vitamin A after intestinal absorption of carotenoids, but little is known about the metabolic transformation of non provitamin A xanthophylls. The enzymatic oxidation of the secondary hydroxyl group leading to keto-carotenoids would occur as a common pathway of xanthophyll metabolism in mammals. This paper reviews the absorption and metabolism of xanthophylls by introducing recent advances in this field.
Asunto(s)
Xantófilas/metabolismo , Xantófilas/farmacocinética , Animales , Dieta , Difusión Facilitada , Humanos , Absorción Intestinal , Mucosa Intestinal/metabolismoRESUMEN
A number of carotenoids with diverse structures are present in foods and have beneficial effects on human health due to their common antioxidant activity and their respective biological activities. The major carotenoids found in human tissues, however, are limited to several including such as ß-carotene, lycopene, and lutein. We have little knowledge of whether carotenoids are selectively absorbed in intestine and metabolized discriminately in the body. Moreover, the metabolic transformation of carotenoids in mammals other than vitamin A formation has not been fully elucidated. Here, the intestinal absorption and oxidative metabolism of dietary carotenoids are reviewed with a focus on dietary xanthophylls.
Asunto(s)
Carotenoides/metabolismo , Animales , Humanos , Luteína/metabolismo , Licopeno , Modelos Biológicos , Xantófilas/metabolismo , beta Caroteno/metabolismoRESUMEN
Fucoxanthin, a xanthophyll present in brown algae consumed in Eastern Asia, can suppress carcinogenesis and obesity in rodents. We investigated the metabolism, tissue distribution, and depletion of fucoxanthin in ICR mice by comparison with those of lutein. The experiments comprised 14-d dietary supplementation with lutein esters or fucoxanthin, followed by 41- or 28-d, respectively, depletion periods with carotenoid-free diets. After lutein ester supplementation, 3'-hydroxy-ε,ε-caroten-3-one and lutein were the predominant carotenoids in plasma and tissues, accompanied by ε,ε-carotene-3,3'-dione. The presence of these keto-carotenoids in mouse tissues is reported here for the first time, to our knowledge. Lutein and its metabolites accumulated most in the liver (7.51 µmol/kg), followed by plasma (2.11 µmol/L), adipose tissues (1.01-1.44 µmol/kg), and kidney (0.87 µmol/kg). The half-life of the depletion (t(1/2)) of lutein metabolites varied as follows: plasma (1.16 d) < liver (2.63 d) < kidney (4.44 d) < < < adipose tissues (>41 d). Fucoxanthinol and amarouciaxanthin A were the main metabolites in mice fed fucoxanthin and partitioned more into adipose tissues (3.13-3.64 µmol/kg) than into plasma, liver, and kidney (1.29-1.80 µmol/kg). Fucoxanthin metabolites had shorter t(1/2) in plasma, liver, and kidneys (0.92-1.23 d) compared with those of adipose tissues (2.76-4.81 d). The tissue distribution of lutein and fucoxanthin metabolites was not associated with their lipophilicity, but depletion seemed to be slower for more lipophilic compounds. We concluded that mice actively convert lutein and fucoxanthin to keto-carotenoids by oxidizing the secondary hydroxyl groups and accumulate them in tissues.
Asunto(s)
Carotenoides/análisis , Luteína/análogos & derivados , Luteína/farmacocinética , Xantófilas/farmacocinética , Tejido Adiposo/química , Animales , Carotenoides/sangre , Suplementos Dietéticos , Ésteres/administración & dosificación , Semivida , Riñón/química , Hígado/química , Luteína/administración & dosificación , Luteína/análisis , Masculino , Ratones , Ratones Endogámicos ICR , Xantófilas/administración & dosificaciónRESUMEN
The effects were evaluated of various glycerophospholipids on the uptake of beta-carotene solubilized in mixed micelles by human intestinal Caco-2 cells. Phosphatidylethanolamine markedly enhanced the transfer of beta-carotene from the micelles to the cells, whereas phosphatidylcholine suppressed it. All the lysoglycerophospholipids enhanced the transfer, irrespective of the polar head group. Glycerophospholipids therefore have the potential to modify the intestinal absorption of carotenoids.
Asunto(s)
Glicerofosfolípidos/clasificación , Glicerofosfolípidos/farmacología , beta Caroteno/metabolismo , Transporte Biológico/efectos de los fármacos , Células CACO-2 , Humanos , Micelas , Solubilidad , beta Caroteno/químicaRESUMEN
Carotenoids are highly hydrophobic pigments with yellow to red color and their major dietary sources are fruits and vegetables. They have an essential physiological function as a vitamin A precursor and also have antioxidant, anticancer, immune enhancement and antiobesity activities related to prevention of degenerative diseases. The release of carotenoids from food matrix, their dispersion within the digestive tract, and their solubilization in mixed micelles are important steps for carotenoid bioaccessibility. Solubilized carotenoids are taken up by epithelial cells of the small intestine by simple diffusion and/or transporter-mediated processes and then secreted to lymph as chylomicron. Carotenoids accumulated in tissues are thought to be metabolized to small molecules by enzymatic cleavage and/or chemical oxidation with active oxygen species at conjugated double bonds. The hydroxyl group of xanthophylls can be oxidatively metabolized to carbonyl group. Carotenoids with long chain of conjugated double bonds physically quench singlet oxygen and scavenge oxygen radicals, particularly under low oxygen pressure, and thereby they have been thought to work as lipophilic antioxidants for human health. In addition to antioxidant activities, each carotenoid has characteristic functions such as cell cycle inhibition, induction of cell differentiation and apoptosis, and enhancement of gap-junctional communication. However, the detailed mechanisms of these biological actions have not been fully revealed yet and deserve future studies.
Asunto(s)
Antioxidantes/metabolismo , Antioxidantes/fisiología , Carotenoides/metabolismo , Carotenoides/fisiología , Animales , Antioxidantes/química , Carotenoides/química , Humanos , Absorción Intestinal , Ratones , RatasRESUMEN
We evaluated the effects of soluble fibers on beta-carotene and lutein micellization during simulated digestion in vitro, and on carotenoid uptake from mixed micelles by Caco-2 cells. Medium- and high-viscosity alginates and pectins inhibited carotenoid micellization and cellular uptake relative to the fiber-free control. Alginates, carboxy-methylcelluloses, and methylcelluloses inhibited beta-carotene uptake mainly by increasing medium viscosity, but pectins might inhibit carotenoid uptake by additional mechanisms.
Asunto(s)
Carotenoides/química , Carotenoides/metabolismo , Micelas , Alginatos/farmacología , Células CACO-2 , Humanos , Luteína , Metilcelulosa/farmacología , Viscosidad , beta Caroteno/metabolismoRESUMEN
We recently found that peridinin, which is uniquely present in dinoflagellates, reduced cell viability by inducing apoptosis in human colon cancer cells. Peridinin is also found in edible clams and oysters because the major food sources of those shellfish are phytoplanktons such as dinoflagellates. Little is known, however, about the fate of dietary peridinin and its biological activities in mammals. The aim of the present study was to investigate the enzymatic esterification of xanthophylls, especially peridinin which is uniquely present in dinoflagellates, using differentiated cultures of Caco-2 human intestinal cells. We found that peridinin is converted to peridininol and its fatty acid esters in differentiated Caco-2 cells treated with 5mumol/L peridinin solubilized with mixed micelles. The cell homogenate was also able to deacetylate peridinin and to esterify peridininol. Other xanthophylls, such as fucoxanthin, astaxanthin and zeaxanthin, were also esterified, but at relatively lower rates than peridinin. In this study, we found the enzymatic esterification of xanthophylls in mammalian intestinal cells for the first time. Our results suggest that the esterification of xanthophylls in intestinal cells is dependent on their polarity.
Asunto(s)
Mucosa Intestinal/metabolismo , Xantófilas/metabolismo , Células CACO-2 , Cromatografía Líquida de Alta Presión , Esterificación , Humanos , Espectrofotometría UltravioletaRESUMEN
Epoxyxanthophylls (epoxide-containing xanthophylls), a group of carotenoids, are ubiquitously distributed in edible plants. Among them, neoxanthin in green leafy vegetables and fucoxanthin in brown algae have been reported to exhibit an antiproliferative effect on several human cancer cells in vitro. However, there is little information about the intestinal absorption and metabolic fate of dietary epoxyxanthophylls in humans. To estimate the intestinal absorption of neoxanthin and fucoxanthin in humans, we evaluated the plasma epoxyxanthophyll concentrations before and after 1-week dietary interventions with spinach (Spinacia oleracea) and wakame (Undaria pinnatifida). The epoxyxanthophylls and their metabolites in the plasma extracts were determined by HPLC after partial purification and concentration with solid-phase extraction cartridges. Even after 1 week of spinach intake (3.0 mg neoxanthin/d), the plasma concentrations of neoxanthin and its metabolites (neochrome stereoisomers) remained very low (about 1 nmol/l), whereas those of beta-carotene and lutein were markedly increased. Similarly, the plasma concentration of fucoxanthinol, a gastrointestinal metabolite of fucoxanthin, was < 1 nmol/l after 1 week of wakame intake (6.1 mg fucoxanthin/d). These results indicated that the plasma response to dietary epoxyxanthophylls was very low in humans even after 1-week intake of epoxyxanthophyll-rich diets.
Asunto(s)
Dieta , Xantófilas/sangre , Adulto , Disponibilidad Biológica , Cromatografía Líquida de Alta Presión/métodos , Femenino , Humanos , Absorción Intestinal , Masculino , Persona de Mediana Edad , Spinacia oleracea/química , Undaria/químicaRESUMEN
Peridinin, which is uniquely present in dinoflagellates, is one of the most abundant carotenoids found in nature. We evaluated the apoptotic effect of peridinin on DLD-1 human colorectal cancer cells. Peridinin significantly reduced the cell viability in a dose-dependent manner (0-20 microM) and induced apoptosis by activating both caspase-8 and caspase-9. Our findings could be important for the high-performance utilization of marine bioproducts.
Asunto(s)
Antineoplásicos/farmacología , Apoptosis/efectos de los fármacos , Carotenoides/farmacología , Neoplasias del Colon/tratamiento farmacológico , Dinoflagelados/química , Animales , Antineoplásicos/aislamiento & purificación , Carotenoides/aislamiento & purificación , Caspasa 8/metabolismo , Caspasa 9/metabolismo , Núcleo Celular/efectos de los fármacos , Núcleo Celular/ultraestructura , Supervivencia Celular/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Activación Enzimática/efectos de los fármacos , Ensayo de Inmunoadsorción Enzimática , HumanosRESUMEN
Highly polar xanthophylls of 9'-cis-neoxanthin (neoxanthin) and fucoxanthin, which have the characteristic structure of an epoxy group and an allenic bond, were previously found to induce apoptosis in human prostate cancer cells. In the present study, we found apoptosis induction by neoxanthin in HCT116 human colon cancer cells and examined the induction mechanism. The cells exposed to 20 microM neoxanthin clearly showed chromatin condensation, DNA fragmentation, and an increase in hypodiploid cells. Neoxanthin treatment increased the activities of caspase-3, -8 and -9, and the protein levels of their active subunits, except in the case of caspase-8. The treatment also caused the loss of mitochondrial transmembrane potential at an early stage and subsequently the release of cytochrome c and apoptosis-inducing factor (AIF) from mitochondria to cytosol. The exposure of neoxanthin directly to mitochondria isolated from the cells enhanced the release of cytochrome c and AIF in a dose-dependent manner. Approximately 50% of the neoxanthin taken up into the HCT116 cells accumulated in the mitochondrial fraction. These results suggest that the accumulation of neoxanthin in mitochondria causes the loss of mitochondrial transmembrane potential and thereafter releases cytochrome c and AIF, leading to the execution of apoptosis.
Asunto(s)
Apoptosis/efectos de los fármacos , Neoplasias del Colon/patología , Mitocondrias/efectos de los fármacos , Mitocondrias/metabolismo , Xantófilas/farmacología , Factor Inductor de la Apoptosis/metabolismo , Caspasas/metabolismo , Proliferación Celular/efectos de los fármacos , Citocromos c/metabolismo , Relación Dosis-Respuesta a Droga , Activación Enzimática/efectos de los fármacos , Células HCT116 , Humanos , Potencial de la Membrana Mitocondrial/efectos de los fármacos , Poli(ADP-Ribosa) Polimerasas/metabolismo , Proteínas Proto-Oncogénicas c-bcl-2/metabolismo , Fracciones Subcelulares/efectos de los fármacos , Factores de Tiempo , Xantófilas/química , Xantófilas/metabolismoRESUMEN
The assessment of carotenoid bioavailability has long been hampered by the limited knowledge of their absorption mechanisms. However, recent reports have elucidated important aspects of carotenoid digestion and absorption. Disruption of food matrix and increasing amounts of fat seem to enhance the absorption of carotenes to a larger extent than that of xanthophylls. Comparing different carotenoid species, xanthophylls seem to be more easily released from the food matrix and more efficiently micellized than the carotenes. On the other hand, carotenes are more efficiently taken up by the enterocytes. However, carotenoid emulsification and micellization steps are largely affected by the food matrix and dietary components, being the main determinant of carotenoid bioavailability from foodstuffs. Although the intestinal uptake of carotenoids has been thought to occur by simple diffusion, recent studies reported the existence of receptor-mediated transport of carotenoids in enterocytes. Comparisons between the intestinal absorption of a wide array of carotenoids would be useful to elucidate the absorption mechanism of each carotenoid species, in view of the recent indications that intestinal carotenoid uptake may involve the scavenger receptor class B type I and possibly other epithelial transporters. The unraveling of the whole mechanism underlying the absorption of carotenoids will be the challenge for future studies.
Asunto(s)
Carotenoides/farmacocinética , Absorción Intestinal , Animales , Transporte Biológico , Carotenoides/administración & dosificación , Fibras de la Dieta/administración & dosificación , Difusión , Ácidos Grasos/administración & dosificación , Humanos , Fitosteroles/administración & dosificación , Receptores Depuradores de Clase B/fisiología , Sacarosa/administración & dosificación , Sacarosa/análogos & derivadosRESUMEN
The intestinal absorption of carotenoids is thought to be mediated by the carotenoid assembly in mixed micelles, followed by its transfer into the enterocytes and subsequent secretion to the lymph as chylomicron particles. In the present study we investigated the effects of phospholipids and lysophospholipids with diverse fatty acyl moieties on the uptake of beta-carotene solubilized in mixed micelles by Caco-2 cells. Compared with phospholipid-free mixed micelles (NoPL), those containing long-chain PC inhibited beta-carotene uptake (16:0,18:1-PC approximately equal to 16:0,18:2-PC < 14:0,14:0-PC approximately equal to 16:0, 14:0-PC < 16:0,16:0-PC < NoPL). However, mixed micelles containing medium-chain PC enhanced beta-carotene uptake (NoPL < 8:0,8:0-PC < 12:0,12:0-PC < 10:0,10:0-PC), and short-chain PC did not affect the uptake. Among the lysophosphatidylcholine (LysoPC) class, a marked increase of beta-carotene uptake by medium-to-long-chain LysoPC was observed (NoPL < 12:0-LysoPC < 14:0-LysoPC < 18:1-LysoPC < 16:0-LysoPC), although short-to-medium-chain LysoPC (6:0-LysoPC to 10:0-LysoPC) did not affect beta-carotene uptake. The long-chain 16:0,18:1-PC increased the beta-carotene efflux from cells and drastically changed the beta-carotene UV-visible absorbance spectrum, compared with those of NoPL micelles. The acyl moieties of long-chain PC may interact with the carotenoid in the micelle interior, shifting the beta-carotene partition toward the micellar phase. Medium-chain PC and long-chain LysoPC, which have nearly equivalent hydrophobicities, may enhance beta-carotene uptake through their interaction with the cell membrane.
Asunto(s)
Ácidos Grasos/metabolismo , Fosfolípidos/metabolismo , beta Caroteno/farmacocinética , Transporte Biológico/efectos de los fármacos , Células CACO-2 , Ácidos Grasos/química , Humanos , Absorción Intestinal/fisiología , Lisofosfatidilcolinas/química , Lisofosfatidilcolinas/metabolismo , Micelas , Fosfolípidos/química , Fosfolípidos/farmacologíaRESUMEN
BACKGROUND: Carotenoids may reduce the risk for diabetes mellitus, but little is known about the association of insulin resistance with serum carotenoids in non-diabetic subjects. This study aimed to investigate whether the homeostasis model assessment-insulin resistance (HOMA-IR) index would be lower in the presence of high serum carotenoid concentrations in non-diabetic subjects. METHODS: A total of 812 subjects (256 males and 556 females) who had received health examinations in 2003 participated in the study. The associations of the serum-carotenoid concentrations and HOMA-IR were evaluated cross-sectionally. The multivariate-adjusted geometric means of HOMA-IR by the tertiles of the serum carotenoid concentration were calculated after adjusting for age, body mass index, systolic blood pressure, total cholesterol, triacylglycerols, current tobacco use, regular alcohol intake, exercise habits and total energy intake. Associations among high HOMA-IR (3.0+mUxmmol/L2) across tertiles of serum carotenoid concentration were assessed by tests for logistic regression analysis. RESULTS: In male subjects, the multivariate adjusted geometric mean of HOMA-IR was inversely associated with the serum beta-cryptoxanthin concentrations. In female subjects, an inverse association of the serum carotenoid concentration and HOMA-IR was observed in lycopene, beta-cryptoxanthin, and zeaxanthin. The confounding factor-adjusted odds ratios (OR) for high HOMA-IR on the highest tertiles of serum alpha-carotene, beta-carotene, beta-cryptoxanthin, and zeaxanthin were 0.18 [95% confidence interval (CI): 0.06-0.52], 0.22 (95% CI: 0.07-0.67), 0.34 (95% CI: 0.12-0.96), and 0.30 (95% CI: 0.11-0.79), respectively, in male subjects. On the other hand, in female subjects, the adjusted OR for high HOMA-IR on the highest tertiles of serum lycopene and beta-cryptoxanthin were 0.39 (95% CI: 0.21-0.73) and 0.51 (95% CI: 0.28-0.95), respectively. CONCLUSIONS: The serum antioxidant carotenoids were inversely associated with HOMA-estimated insulin resistance in non-diabetic subjects.