Tocopherol Accumulation Research Articles

An allele of ZmPORB2 encoding a protochlorophyllide oxidoreductase promotes tocopherol accumulation in both leaves and kernels of maize.

Phytol is one of the key precursors for tocopherol synthesis in plants, however, the underlying mechanisms concerning the accumulation of tocopherol remain poorly understood. In this study, qVE5, a major QTL affecting tocopherol accumulation in maize kernels was identified via a positional cloning approach. qVE5 encodes a protochlorophyllide oxidoreductase (ZmPORB2), which localizes to the chloroplast. Overexpression of ZmPORB2 increased tocopherol content in both leaves and kernels. Candidate gene association analysis identified a 5/8-bp insertion/deletion (InDel058) in the 5' untranslated region (UTR) as the causal polymorphism in affecting ZmPORB2 expression and being highly associated with tocopherol content. We showed that higher expression of ZmPORB2 correlated with more chlorophyll metabolites in the leaf following pollination. RNA-sequencing and metabolic analysis in near isogenic lines (NILs) support that ZmPORB2 participates in chlorophyll metabolism enabling the production of phytol, an important precursor of tocopherol. We also found that the tocopherol content in the kernel is mainly determined by the maternal genotype, a fact that was further confirmed by in vitro culture experiments. Finally, a PCR-based marker based on Indel058 was developed in order to facilitate the high tocopherol (vitamin E) maize breeding.

Deciphering the genetic basis for vitamin E accumulation in leaves and grains of different barley accessions

Tocopherols and tocotrienols, commonly referred to as vitamin E, are essential compounds in food and feed. Due to their lipophilic nature they protect biomembranes by preventing the propagation of lipid-peroxidation especially during oxidative stress. Since their synthesis is restricted to photosynthetic organisms, plant-derived products are the major source of natural vitamin E. In the present study the genetic basis for high vitamin E accumulation in leaves and grains of different barley (Hordeum vulgare L.) accessions was uncovered. A genome wide association study (GWAS) allowed the identification of two genes located on chromosome 7H, homogentisate phytyltransferase (HPT-7H) and homogentisate geranylgeranyltransferase (HGGT) that code for key enzymes controlling the accumulation of tocopherols in leaves and tocotrienols in grains, respectively. Transcript profiling showed a correlation between HPT-7H expression and vitamin E content in leaves. Allele sequencing allowed to decipher the allelic variation of HPT-7H and HGGT genes corresponding to high and low vitamin E contents in the respective tissues. Using the obtained sequence information molecular markers have been developed which can be used to assist smart breeding of high vitamin E barley varieties. This will facilitate the selection of genotypes more tolerant to oxidative stress and producing high-quality grains.

TOCOPHEROLS OF FRUIT PULP OF FOUR SEABUCKTHORN (HIPPOPHAE RHAMNOIDES L.) SUBSPECIES IN FOREST-STEPPE CONDITIONS OF ALTAI TERRITORY

The aim of the study was to study tocopherols in the fruits of various sea buckthorn ecotypes ssp. mongolica in comparison with other subspecies. The composition of tocopherols in fruit pulp of four subspecies of sea buckthorn – H. rhamnoides ssp. mongolica, ssp. turkestanica, ssp. fluviatilis and ssp. carpatica, growing at Lisavenko Research Institute of Horticulture for Siberia in forest-steppe conditions of Altai territory has been studied. The research has been focused on the most promising subspecies from the point of view of industrial utilization – H. rhamnoides ssp. mongolica, in order to identify possible variation in accumulation of different tocopherols in fruit pulp depending on ecotype, period of collection of fruits as well as conditions of the year.
 It was established that the major tocopherol in the pulp of the fruit of sea buckthorn is α-tocopherol. β -, γ-and δ-tocopherols were characterized by low content. Within subspecies H. rhamnoides ssp. mongolica most fractions of tocopherols (except δ-tocopherol) have relatively high coefficient of variation, which exceeds of that for the whole group of evaluated varieties. That result does not allow us to use this criteria as a reliable background for preliminary systematic identification of evaluated varieties.

Full-Length Transcriptome Analysis of the Genes Involved in Tocopherol Biosynthesis in Torreya grandis.

The seeds of Torreya grandis (Cephalotaxaceae) are rich in tocopherols, which are essential components of the human diet as a result of their function in scavenging reactive oxygen and free radicals. Different T. grandis cultivars (10 cultivars selected in this study were researched, and their information is shown in Table S1 of the Supporting Information) vary enormously in their tocopherol contents (0.28-11.98 mg/100 g). However, little is known about the molecular basis and regulatory mechanisms of tocopherol biosynthesis in T. grandis kernels. Here, we applied single-molecule real-time (SMRT) sequencing to T. grandis (X08 cultivar) for the first time and obtained a total of 97 211 full-length transcripts. We proposed the biosynthetic pathway of tocopherol and identified eight full-length transcripts encoding enzymes potentially involved in tocopherol biosynthesis in T. grandis. The results of the correlation analysis between the tocopherol content and gene expression level in the 10 selected cultivars and different kernel developmental stages of the X08 cultivar suggested that homogentisate phytyltransferase coding gene ( TgVTE2b) and γ-tocopherol methyltransferase coding gene ( TgVTE4) may be key players in tocopherol accumulation in the kernels of T. grandis. Subcellular localization assays showed that both TgVTE2b and TgVTE4 were localized to the chloroplast. We also identified candidate regulatory genes similar to WRI1 and DGAT1 in Arabidopsis that may be involved in the regulation of tocopherol biosynthesis. Our findings provide valuable genetic information for T. grandis using full-length transcriptomic analysis, elucidating the candidate genes and key regulatory genes involved in tocopherol biosynthesis. This information will be critical for further molecular-assisted screening and breeding of T. grandis genotypes with high tocopherol contents.

Impact of exogenously applied tocopherol on some key physio-biochemical and yield attributes in mungbean [Vigna radiata (L.) Wilczek] under limited irrigation regimes

The lipophilic vitamin E, α-Tocopherol (α-Toc), has been considered as a potent cellular antioxidant naturally occurring in biological membranes. It plays a number of key metabolic roles in plants exposed to various stressful cues. A field experimental was conducted on mungbean [Vigna radiata (L.) Wilczek] under varying water-limited regimes and the plants were sprayed with four levels of α-Toc (0, 100, 200, and 300 mg L−1) at the vegetative stage of plant growth. The results showed that limited field irrigation regimes (desiccated conditions) caused a marked reduction in growth parameters (shoot and root fresh and dry weights; shoot and root lengths), photosynthetic pigments (chlorophyll a and b), total soluble proteins (TSP) and yield attributes (number of pods, seeds per plant, weight of ripened pods and 100-seeds weight), while, in contrast, water deficiency induced an increase in phenolics, proline, glycine betaine (GB), hydrogen peroxide (H2O2), malondialdehyde (MDA), reducing and non-reducing sugars, total free amino acids, endogenous tocopherol levels, and activities of antioxidant enzymes including superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT). However, the foliar spray of α-Toc significantly improved shoot and root fresh and dry weights, shoot and root lengths, chlorophyll a and b contents, phenolics, proline, GB, reducing and non-reducing sugars, TSP, total free amino acids, endogenous tocopherol level, and activities of antioxidant enzymes (SOD, POD, and CAT), as well as yield parameters. On the other hand, it significantly decreased the MDA and H2O2 levels. Of all varying levels of α-Toc used, 100 mg L−1 was most effective in causing enhanced accumulation of ascorbic acid (AsA), MDA, and cellular tocopherols particularly in cv. Cyclone 7008, while proline and catalase in cv. Cyclone 8009. Of both cultivars, Cyclone 7008 was superior to the other cultivar in proline, TSP, SOD, and POD enzymes, but cv. Cyclone 8009 being superior in shoot fresh weights, root fresh weight, shoot and root lengths, chlorophyll a and b, phenolics, H2O2, AsA, MDA, CAT, number of pods, seeds, weight of ripened pods, and weight of 100 seeds under dry land conditions. Overall, exogenously applied tocopherol improved yield and myriad of key physio-biochemical attribute in mungbean.

Increased leaf tocopherol and β‐carotene content is associated with the tolerance of winter wheat cultivars to frost

AbstractComparative studies in winter wheat cultivars have so far been focused on the content of tocopherols in the grains as tocopherols are an important source of vitamin E in the human diet. Our approach was to verify the following main hypothesis—whether a higher accumulation of nonenzymatic antioxidants (tocopherol, tocotrienols, β‐carotene) in the leaves of winter wheat during cold acclimation is accompanied by a higher frost tolerance of winter wheat cultivars. Seedlings of winter wheat cultivars—frost susceptible (Bystra) and frost tolerant (Nutka and Smuga)—were cold acclimated for a period of 3 weeks. To analyse the antioxidants (tocotrienols, tocopherols, β‐carotene), leaf samples were taken on the final day of the exposure to cold. Moreover, samples were also taken to estimate the content of abscisic acid, jasmonic acid and salicylic acid. After leaf chlorophyllafluorescence measurements, the plants were exposed to frost (−8 to −14°C) and left to regrow to estimate their survival. Cultivars of winter wheat with higher accumulation of tocopherols in leaves had higher frost tolerance than cultivar with fewer tocopherols in leaves. α‐tocopherol was accumulated in cv. Bystra in the amount of 137 μg gDW−1. The content of α‐tocopherol was about 26% and 90% higher in cv. Nutka and cv. Smuga, respectively. The β‐carotene content was also higher in cv. Nutka and cv. Smuga compared to cv. Bystra. This work indicates a need for further and more detailed studies on the role of tocopherols and carotenoids in the acclimation process of cereals (winter wheat) to low temperatures. The accumulation of nonenzymatic antioxidants in the cold acclimation process will be discussed against the background of the accumulation of the stress hormones and changes in the photosynthetic efficiency in the tested cultivars.

Maizew3disrupts homogentisate solanesyl transferase(ZmHst) and reveals a plastoquinone-9 independent path for phytoene desaturation and tocopherol accumulation in kernels.

Maize white seedling 3 (w3) has been used to study carotenoid deficiency for almost 100years, although the molecular basis of the mutation has remained unknown. Here we show that the w3 phenotype is caused by disruption of the maize gene for homogentisate solanesyl transferase (HST), which catalyzes the first and committed step in plastoquinone-9 (PQ-9) biosynthesis in the plastid. The resulting PQ-9 deficiency prohibits photosynthetic electron transfer and eliminates PQ-9 as an oxidant in the enzymatic desaturation of phytoene during carotenoid synthesis. As a result, light-grown w3 seedlings are albino, deficient in colored carotenoids and accumulate high levels of phytoene. However, despite the absence of PQ-9 for phytoene desaturation, dark-grown w3 seedlings can produce abscisic acid (ABA) and homozygous w3 kernels accumulate sufficient carotenoids to generate ABA needed for seed maturation. The presence of ABA and low levels of carotenoids in w3 nulls indicates that phytoene desaturase is able to use an alternate oxidant cofactor, albeit less efficiently than PQ-9. The observation that tocopherols and tocotrienols are modestly affected in w3 embryos and unaffected in w3 endosperm indicates that, unlike leaves, grain tissues deficient in PQ-9 are not subject to severe photo-oxidative stress. In addition to identifying the molecular basis for the maize w3 mutant, we: (1) show that low levels of phytoene desaturation can occur in w3 seedlings in the absence of PQ-9; and (2) demonstrate that PQ-9 and carotenoids are not required for vitamin E accumulation.

Quantitative Analysis of the Accumulation of Marine-derived Tocopherol in the Tissue of Mice Fed with Salmon Roe Oil Using HPLC-fluorescence.

In this study, we measured the quantity of marine-derived tocopherol (MDT), a monounsaturated vitamin E (VE), stored in the body tissue of mice fed with a diet containing a VE-rich fraction extracted from salmon roe. We first prepared the calibration curves for the MDT concentration using an HPLC-fluorescence system. Ranging from 0.016 to 50 μg/mL, the slope was expressed as first-order equations, with R2 values = 0.99. The mice were fed with an AIN-93 based diet containing MDT in doses of 21.4 mg/kg for 4 weeks, and the storage in the heart, lung, liver, stomach, small intestine, large intestine, kidney, pancreas, spleen, testis, skeletal muscle, visceral white adipose tissue (WAT), subcutaneous WAT and brain was quantified. MDT was widely distributed in tissues throughout the whole body, with higher accumulations observed in the adipose tissue, liver and kidney. These results demonstrate means to estimating the MDT concentration in natural products and in the bodies of animals and contribute to the understanding of the physiological functions of MDT in relation to human health.

WRINKLED1 and ACYL-COA:DIACYLGLYCEROL ACYLTRANSFERASE1 regulate tocochromanol metabolism in Arabidopsis.

Photosynthetic organisms such as plants, algae and some cyanobacteria synthesize tocochromanols, a group of compounds that encompasses tocopherols and tocotrienols and that exhibits vitamin E activity in animals. While most vitamin E biosynthetic genes have been identified in plant genomes, regulatory genes controlling tocopherol accumulation are currently unknown. We isolated by forward genetics Arabidopsis enhanced vitamin E (eve) mutants that overaccumulate the classic tocopherols and plastochromanol-8, and a tocochromanol unknown in this species. We mapped eve1 and eve4, and identified the unknown Arabidopsis tocochromanol by using a combination of analytical tools. In addition, we determined its biosynthetic pathway with a series of tocochromanol biosynthetic mutants and transgenic lines. eve1 and eve4 are two seed lipid mutants affecting the WRINKLED1 (WRI1) and ACYL-COA:DIACYLGLYCEROL ACYLTRANSFERASE1 (DGAT1) genes, respectively. The unknown tocochromanol is 11'-12' γ-tocomonoenol, whose biosynthesis is VITAMIN E 1 (VTE1) - and VTE2-dependent and is initiated by the condensation of homogentisate (HGA) and tetrahydrogeranylgeranyl pyrophosphate. This study identifies the first two regulatory genes, WRI1 and DGAT1, that control the synthesis of all tocochromanol forms in seeds, and shows the existence of a metabolic trade-off between lipid and tocochromanol metabolisms. Moreover, it shows that Arabidopsis possesses a tocomonoenol biosynthetic pathway that competes with tocopherol synthesis.

Tocopherol levels in different mango varieties correlate with MiHPPD expression and its over-expression elevates tocopherols in transgenic Arabidopsis and tomato.

Mango fruit tocopherol levels vary in different varieties during ripening. This study shows that tocopherol accumulation is highly correlated with its p-hydroxyphenyl pyruvate dioxygenase (MiHPPD) gene expression during ripening. MiHPPD transcript is ethylene induced and differentially expressed in four mango varieties used in this study. Higher/lower accumulation of tocopherol (mainly α-tocopherol) was achieved by heterologous expression of MiHPPD in Arabidopsis and tomato. The results suggest that tocopherol accumulation in mango fruit is correlated to MiHPPD gene expression. Over-expression of MiHPPD gene channelizes the flux towards tocophreol biosynthesis and could be used as a potential tool for metabolic engineering.

Dynamics of oil and tocopherol accumulation in sunflower grains and its impact on final oil quality

Tocopherols are one of the most important bioactive compounds in vegetable oils. It is known that these antioxidants present a dilution like relationship with oil weight per grain but the mechanism underlying this relationship are unknown. The aim of this work was to analyze the dynamics of tocopherol accumulation in sunflower grains, its relationship with oil accumulation and its effects on final oil quality in genotypes with different fatty acid composition. Three field experiments were conducted with genotypes with different potential fatty acid composition (a traditional, a high oleic and a high stearic−high oleic) and treatments with different source (intercepted solar radiation) or sink (grains) during grain filling to obtain varied grain filling conditions and grains with different oil concentration and oil unsaturation. Intercepted solar radiation modified oil per grain but did not affect tocopherol per grain. The rate of accumulation explained 79% and 74% of the oil and tocopherol per grain variation, respectively. When intercepted solar radiation increased, the duration of the period of oil and tocopherols accumulation increased, being the first the most responsive. These differences in the duration of accumulation periods are reflected in a larger relative increase in oil than tocopherols per grain and thus a dilution of the latter in the oil. These differences in the dynamics of oil and tocopherol accumulation are common to genotypes with different level of unsaturation. These results help to understand the mechanism associated with the dilution curve of oil tocopherol concentration reported in the literature.

Solid carbon dioxide to promote the extraction of extra-virgin olive oil

The use of solid carbon dioxide (dry ice) as a cryogen is widespread in the food industry to produce high quality wines, rich in color and perfumes. The direct addition of carbon dioxide to olives in the solid state before milling represents a fundamental step which characterizes this innovative extraction system. At room temperature conditions solid carbon dioxide evolves directly into the air phase (sublimation), and the direct contact between the cryogen and the olives induces a partial solidification of the cellular water inside the fruits. Since the volume occupied by water in the solid state is higher than that in the liquid state, the ice crystals formed are incompatible with the cellular structure and induce the collapse of the cells, besides promoting the diffusion of the cellular substances in the extracted oil, which is thus enriched with cellular metabolites characterized by a high nutraceutical value. Furthermore, a layer of CO 2 remains over the olive paste to preserve it from oxidative degradation. The addition of solid carbon dioxide to processed olives induced a statistically significant increase in oil yield and promoted the accumulation of tocopherols in the lipid phase, whereas a not significant increase in the phenolic fraction of the oil occurred.

Vitamin E Homologs and γ‐Oryzanol Levels in Rice (Oryza sativa L.) During Seed Development

Vitamin E homologs (tocopherols and tocotrienols) and γ‐oryzanol have gained significant attention because of their proposed health benefits and ability to increase vegetable oil stability. Changes in the levels of these phytochemicals were examined during seed development. Rapid accumulation of tocopherols, tocotrienols, and γ‐oryzanol occurred during early seed development. During the middle stage of seed development, the levels of tocopherols decreased sharply, and the levels of tocotrienols either stayed the same or decreased slightly, whereas γ‐oryzanol continued to accumulate until maturity. The levels of these compounds remained constant from maturity to 15 days postmaturity. In conclusion, rice grain for nutraceutical and functional food applications should be harvested during its immature stage to obtain the highest amount of tocopherols, whereas the amounts of the other phytochemicals that were studied can be optimized by harvesting grain at maturity.

Effect of Genotype, Environment, and Genotype × Environment Interaction on Tocopherol Accumulation in Soybean Seed

ABSTRACTSoybean seeds [Glycine max (L.) Merrill] are a major source of tocopherols that provide many human health benefits including decrease in lung cancer risk and osteoporosis. The objectives of this study were: (i) to determine the impact of genotype, environment, and genotype × environment on soybean seed tocopherols and (ii) to evaluate relationships between agronomic traits and tocopherols. Seventy‐nine recombinant inbred lines (RILs) from the cross OAC Bayfield × OAC Shire were grown in three field locations in southern Ontario, Canada, in 2009 and 2010. Agronomic and seed quality data were collected in each location. Significant differences (P < 0.001) for the α‐, γ‐, δ‐, and total tocopherol concentrations were found in the seed of RILs using combined ANOVA for 2009 and 2010. Of the two parental lines, OAC Bayfield accumulated more total tocopherol at most environments. Genotype, location, and year differences were significant as well as genotype × location, location × year, and line × year interactions. Broad‐sense heritability estimates were 0.38 for α‐, 0.47 for γ‐, and 0.35 for δ‐tocopherol. None of the agronomic traits were consistently correlated with any of the tocopherol components; however, oil and protein concentration were correlated to some tocopherols in some of the environments. The wide range in values for α‐, γ‐, δ‐, and total tocopherols among the RIL population that exceeded both parents provided evidence for transgressive segregation. Our results suggest that soybean producers should take locations and genotypes into account when growing soybean for enhanced tocopherol production.

Supplementation effects of seleno-compounds, carnosic acid, and fish oil onconcentrations of fatty acids, tocopherols, cholesterol, and amino acids in the livers of lambs

Lambs were fed a diet containing 3% rapeseed oil (RO) (the RO diet), a diet with 2% RO and 1% fish oil (FO) (the FO diet), or diets with combined additions of 2% RO, 1% FO, 0.1% carnosic acid (CA) (the CA diet), and 0.35 ppm Se as selenized yeast (SeY) (the CASeY diet) or selenate (SeVI) (the CASeVI diet). The CASeVI diet most effectively increased the body mass gain of lambs, while it most efficiently decreased the liver mass. The CASeVI diet most efficiently reduced the concentration of cholesterol and the lipid peroxidation in the liver. The CA diet revealed a weaker protective effect against peroxidation damage and/or catabolism of polyunsaturated fatty acids (PUFAs) than the CASeY or CASeVI diet. Diets containing CA, especially with SeY or SeVI, stimulated the accumulation of tocopherols in the liver. Diets containing FO without/with CA, SeY, or SeVI stimulated the concentration of fatty acids in the liver, while they decreased the concentration of amino acids. Diets containing CA more efficiently stimulated the concentration of PUFAs than the RO and FO diets. The CA-supplemented diet with SeVI and especially that with SeY resulted in the highest increase in the concentration of PUFAs in the liver.

Molecular cloning and heterologous expression analysis of JrVTE1 gene from walnut (Juglans regia).

Tocopherol cyclase (VTE1) plays a key role in promoting the production of γ-tocopherol and improving total tocopherol content in photosynthetic organisms. Walnut is an important source of tocopherols in the human diet, and γ-tocopherol is the major tocopherol compound in walnut kernels. In this study, a full-length cDNA of the VTE1 gene was isolated from walnut using RT-PCR and RACE, and designated as JrVTE1. The full-length cDNA of the JrVTE1 gene contained a 1353-bp open-reading frame encoding a 451-amino-acid protein with a calculated molecular weight of 49.5 kDa. The deduced JrVTE1 protein had a considerable homology with other plant VTE1s and belonged to the tocopherol cyclase family. Functional characterization of JrVTE1 by heterologous expression was carried out in E. coli BL21 (DE3) and microshoot lines of the fruit trees jujube (Zizyphus jujuba var. spinosa) and pear (Pyrus communis) cultivar ‘Old Home’. JrVTE1 in E. coli expressed as a 50 kDa protein, as expected. One or two copies of the transferred JrVTE1 gene were detected in the genomes of representative transgenic lines (from the initial transgenic plants) of jujube and pear by gel blots analysis. Over-expression of JrVTE1 in jujube and pear resulted in an accumulation of tocopherol and a shift in tocopherol composition in leaf, root and stem tissues. In the transgenic jujube, the total tocopherol content increased by 29.8 μg/g in the stems of line J3, 43.7 and 22.5 μg/g in the roots and leaves of line J1, respectively, whereas in the transgenic pear it increased by 47.3 μg/g in the leaf of line P3, and 16.7 and 10.4 μg/g in roots and stems of line P9, respectively. In the examined tissues of transgenic plants, the highest accumulation rate was the γ-tocopherol. These results indicate that JrVTE1 is one of the rate-limiting enzymes for tocopherol production and could be used to improve the tocopherol content of tree crops through genetic engineering. Electronic supplementary materialThe online version of this article (doi:10.1007/s11032-015-0414-2) contains supplementary material, which is available to authorized users.

Homogentisate phytyltransferase from the unicellular green alga Chlamydomonas reinhardtii

Homogentisate phytyltransferase (HPT) (EC 2.5.1.-) catalyzes the first committed step of tocopherol biosynthesis in all photosynthetic organisms. This paper presents the molecular characterization and expression analysis of HPT1 gene, and a study on the accumulation of tocopherols under different environmental conditions in the unicellular green alga Chlamydomonas reinhardtii. The Chlamydomonas HPT1 protein conserves all the prenylphosphate- and divalent cation-binding sites that are found in polyprenyltransferases and all the amino acids that are essential for its catalytic activity. Its hydrophobicity profile confirms that HPT is a membrane-bound protein. Chlamydomonas genomic DNA analysis suggests that HPT is encoded by a single gene, HPT1, whose promoter region contains multiple motifs related to regulation by jasmonate, abscisic acid, low temperature and light, and an ATCTA motif presents in genes involved in tocopherol biosynthesis and some photosynthesis-related genes. Expression analysis revealed that HPT1 is strongly regulated by dark and low-temperature. Under the same treatments, α-tocopherol increased in cultures exposed to darkness or heat, whereas γ-tocopherol did it in low temperature. The regulatory expression pattern of HPT1 and the changes of tocopherol abundance support the idea that different tocopherols play specific functions, and suggest a role for γ-tocopherol in the adaptation to growth under low-temperature.

Anthocyanin, Carotenoid, Tocopherol, and Ellagitannin Content of Red Raspberry Cultivars Grown under Field or High Tunnel Cultivation in the Southeastern United States

High tunnels have been widely adopted for red raspberry (Rubus idaeus) production in the United States to extend the harvest season and increase yields. In this study, effects of high tunnel production on contents of plant secondary metabolites (anthocyanins, carotenoids, tocopherols, and ellagitannins) in red raspberry fruit were determined for three fall-fruiting cultivars (Autumn Britten, Caroline, and Nantahala) grown at three locations in North Carolina under field and high tunnel cultivation systems. Cultivar was the primary contributing factor to variation in phytochemicals, with minor effects of location and production system. The anthocyanin cyanidin-3-glucoside and the carotenoids α-carotene, β-carotene, lutein, and zeaxanthin were higher in fruit produced in field compared with tunnel cultivation (P < 0.01). Accumulation of total anthocyanins and tocopherols in fruit were unaffected by high tunnel cultivation in comparison with traditional field cultivation. Carotenoid content varied by genotype and production system. ‘Autumn Britten’ and ‘Caroline’ showed no difference, but were higher than ‘Nantahala’ for α-carotene, β-carotene, 9-cis-β-carotene, and lutein + zeaxanthin (P < 0.0001). Phytochemical differences among field and tunnel produced fruit have important implications for breeding with increased nutritional value in mind, and also the understanding of the relationships of plant pigments to light and temperature.

A genetic dissection of intestinal fat-soluble vitamin and carotenoid absorption.

Carotenoids are currently investigated regarding their potential to lower the risk of chronic disease and to combat vitamin A deficiency. Surprisingly, responses to dietary supplementation with these compounds are quite variable between individuals. Genome-wide studies have associated common genetic polymorphisms in the BCO1 gene with this variability. The BCO1 gene encodes an enzyme that is expressed in the intestine and converts provitamin A carotenoids to vitamin A-aldehyde. However, it is not clear how this enzyme can impact the bioavailability and metabolism of other carotenoids such as xanthophyll. We here provide evidence that BCO1 is a key component of a regulatory network that controls the absorption of carotenoids and fat-soluble vitamins. In this process, conversion of β-carotene to vitamin A by BCO1 induces via retinoid signaling the expression of the intestinal homeobox transcription factor ISX. Subsequently, ISX binds to conserved DNA-binding motifs upstream of the BCO1 and SCARB1 genes. SCARB1 encodes a membrane protein that facilitates absorption of fat-soluble vitamins and carotenoids. In keeping with its role as a transcriptional repressor, SCARB1 protein levels are significantly increased in the intestine of ISX-deficient mice. This increase results in augmented absorption and tissue accumulation of xanthophyll carotenoids and tocopherols. Our study shows that fat-soluble vitamin and carotenoid absorption is controlled by a BCO1-dependent negative feedback regulation. Thus, our findings provide a molecular framework for the controversial relationship between genetics and fat-soluble vitamin status in the human population.

Carotenoids and fat-soluble vitamins in horse tissues: a comparison with cattle

Carotenoids are important for human health because of their provitamin A function among other biological actions. Their implication on consumer point of view of cattle products have been widely studied, but very little information is available for horse products. The aim of this study was to study the accumulation of carotenoids, retinoids and tocopherol by HPLC and HPLC-MS analysis in different horse tissues (plasma, milk, adipose tissue and liver) and compare it with that of cattle. Fat color was also studied. Four groups of animals were studied (15 animals within each group): lactating mares (709.82±23.09 kg) and cows (576.93±31.94 kg) reared outdoors; and foals (556.8±25.9 kg, 14 months old) and calves (474.7±36.2 kg, 14 months old) reared indoors. Both mares and foals were from the Hispano–Breton breed, whereas both cows and calves belonged to the commercial crossbred Limousine–Retinta. Differences in plasma and milk carotenoids (P<0.05, P<0.001) were found between mares and cows. Similar levels of vitamin A accumulation in the plasma and fat were detected in foals and calves (P>0.05). Both species showed different levels of accumulation of retinoids in the liver, with the foal having better accumulation (P<0.01, P<0.001). These results indicate that there are species-specific differences in the accumulation of carotenoids, retinol and tocopherol, but further studies are required to establish the mechanism of these differences.