Beyond vitamin E supplementation: an alternative strategy to improve vitamin E status

Use of Grape By-Products to Enhance Meat Quality and Nutritional Value in Monogastrics

Grape by-products could be used in monogastric animals′ nutrition to reduce feeding costs with conventional crops (e.g., maize and soybean meal) and to improve meat quality. The main grape by-products with the largest expression worldwide, particularly in the Mediterranean region, are grape pomace, grape seed, grape seed oil and grape skins. These by-products are rich sources of bioactive polyphenols, dietary fiber and polyunsaturated fatty acids (PUFA), more specifically, the beneficial n-3 PUFA, that could be transferred to pork and poultry meat. The potential biological activities, mainly associated with antimicrobial and antioxidant properties, make them putative candidates as feed supplements and/or ingredients capable of enhancing meat quality traits, such as color, lipid oxidation and shelf life. However, grape by-products face several limitations, namely, the high level of lignified cell wall and tannin content, both antinutritional compounds that limit nutrients absorption. Therefore, it is imperative to improve grape by-products’ bioavailability, taking advantage of enzyme supplementation or pretreatment processes, to use them as feed alternatives contributing to boost a circular agricultural economy. The present review summarizes the current applications and challenges of using grape by-products from the agro-industrial sector in pig and poultry diets aiming at improving meat quality and nutritional value.

Polyphenols: Bioavailability, Microbiome Interactions and Cellular Effects on Health in Humans and Animals

Polyphenolic compounds have a variety of functions in plants including protecting them from a range of abiotic and biotic stresses such as pathogenic infections, ionising radiation and as signalling molecules. They are common constituents of human and animal diets, undergoing extensive metabolism by gut microbiota in many cases prior to entering circulation. They are linked to a range of positive health effects, including anti-oxidant, anti-inflammatory, antibiotic and disease-specific activities but the relationships between polyphenol bio-transformation products and their interactions in vivo are less well understood. Here we review the state of knowledge in this area, specifically what happens to dietary polyphenols after ingestion and how this is linked to health effects in humans and animals; paying particular attention to farm animals and pigs. We focus on the chemical transformation of polyphenols after ingestion, through microbial transformation, conjugation, absorption, entry into circulation and uptake by cells and tissues, focusing on recent findings in relation to bone. We review what is known about how these processes affect polyphenol bioactivity, highlighting gaps in knowledge. The implications of extending the use of polyphenols to treat specific pathogenic infections and other illnesses is explored.

Condensed Tannins as Antioxidants in Ruminants-Effectiveness and Action Mechanisms to Improve Animal Antioxidant Status and Oxidative Stability of Products

Condensed tannins (CTs) are widely distributed in plants, and due to their recognized antioxidant activity are considered as possible natural antioxidants for application in ruminant diets. A wide range of CT-rich sources has been tested in ruminant diets, and their effects on animal antioxidant status and oxidative stability of their products are reviewed in the present work. Possible mechanisms underlying the CT antioxidant effects in ruminants are also discussed, and the CT chemical structure is briefly presented. Utilization of CT-rich sources in ruminant feeding can improve the animals' antioxidant status and oxidative stability of their products. However, the results are still inconsistent. Although poorly understood, the evidence suggests that CTs can induce an antioxidant effect in living animals and in their products through direct and indirect mechanisms, which can occur by an integrated and synergic way involving: (i) absorption of CTs with low molecular weight or metabolites, despite CTs' poor bioavailability; (ii) antioxidant action on the gastrointestinal tract; and (iii) interaction with other antioxidant agents. Condensed tannins are alternative dietary antioxidants for ruminants, but further studies should be carried out to elucidate the mechanism underlying the antioxidant activity of each CT source to design effective antioxidant strategies based on the use of CTs in ruminant diets.

Health Effects of Dyes, Minerals, and Vitamins Used in Cosmetics

The average woman uses 12 different cosmetic products every day, but they can have a negative effect on human health. Therefore, in recent years, consumer preferences have changed towards buying natural or ecological cosmetics free from preservatives or unnecessary dyes. The aim of this work is to discuss the use of dyes, minerals, and vitamins in cosmetics in terms of their safety and impact on human health. These substances are very important in the cosmetics industry. Most of them are of natural origin. Some minerals used in the production of face masks or creams are recommended to work against inflammations such as ulcers and acne. Clay minerals have exceptional qualities, among others, low or no toxicity and high bio-compatibility. However, some of them may be harmful. For example, the safety of using talc has been widely debated in recent years. Cosmetic-grade talc cannot contain detectable fibrous asbestos minerals. Moreover, talc should not be applied to the skin when the epidermal barrier is missing or significantly disrupted. The use of talc in cosmetic products in the European Union is restricted. Vitamins are one of the most commonly used, biologically active, and easily accessible components in cosmetics. For example, provitamin B5 (D-panthenol) is a bioactive substance. In cosmetic preparations, it has a softening, repairing, and anti-inflammatory effect and is responsible for regulating sebum secretion. However, some vitamins may be harmful to human health. For example, the use of skin-whitening cosmetics containing vitamin C causes allergic contact dermatitis, whereas the most common adverse effect of topical use of vitamin A is skin irritation, erythema, and peeling. Dyes, which are used to color cosmetics, do not improve the condition of the skin, hair, or nails. Some of them may be harmful to human health. For example, the dye CI 60730 (Acid Violet 43) is prohibited for use in eye products and cosmetics that have contact with mucous membranes. In conclusion, some of the popular cosmetic ingredients discussed in this paper may exert a negative influence on human health, and many of these harmful effects have been discovered recently. Therefore, there is a need for further studies on the possible negative effects of dyes, minerals, and vitamins used in cosmetic products.

Novel PEGylated derivatives of α-tocopherol for nanocarrier formulations; synthesis, characterization and in vitro cytotoxicity against MCF-7 breast cancer cells

Despite numerous beneficial therapeutic effects namely antioxidant and anti-inflammatory activity, Vitamin E has limited clinical applications due to its low water solubility. Throughout the present work, α-tocopherol's new PEGylated derivatives alongside with polyethylene glycol 300 (α-¹TPGT³⁰⁰), 400 (α-TPGT⁴⁰⁰), and 1000 (α-TPGT¹⁰⁰⁰) were synthesized. A 1,2,3-triazole ring was utilized as a linker for the attachment of alpha tocopherol to the PEGs through a click reaction. The purified derivatives were characterized by the means of ¹H NMR, ¹³C NMR, mass spectroscopy, UV-vis and FT-IR methods. Synthesized derivatives' capacity to produce self-assembly nanoparticles was evaluated employing the critical micelle concentration (CMC) values. The stability of the micelles was studied by size analysis. In vitro cytotoxicity of the products was investigated using MTT assay against MCF-7 breast cancer cells. The IC₅₀ value for TPGT¹⁰⁰⁰ after 24 h treatment was 15.0 ± 1.8 µM, whereas no significant cytotoxicity effect was observed following the treatment of MCF-7 cells by TPGT^{300, 400}. The present study showed that polymeric micelle TPGT¹⁰⁰⁰ possessed better physicochemical and biological properties including relatively lower CMC value, higher stability in FBS environment in addition to higher cytotoxicity against MCF-7 breast cancer cells compared to the lower molecular weight PEGylated derivatives. These results confirmed that increasing PEG chain length left a positive effect on the polymeric micelle properties and also improved the cytotoxicity effect of new PEGylated vitamin E derivatives.

Indigenous Crop Production for Sustainable Livelihoods: a Case of uninga in the Rural Areas of South-Eastern Zimbabwe

South-eastern parts of Zimbabwe lie in drought-stricken agricultural region five, characterised by low and erratic rainfall patterns. To realise food security people in the region have resorted to growing drought resistant crops such as sorghum. The recent observations are that the success of sorghum as a drought resistant crop is accompanied by ambivalence as some people view the crop to be unsuitable as a staple food while others rely on it to cope with food insecurity. Some families have resorted to farming cash crops such as cotton and use the dividends to buy maize meal as the staple food. However, recently some farmers have started intensive production of uninga, an indigenous crop which had almost become extinct among the Ndau people (an ethnic grouping of Ndau-speaking) of south-eastern Zimbabwe. The production of this crop is under-researched and understudied in Zimbabwe. To fill this lacuna, we adopted a participatory case study research approach to explore the nature and scope of uninga production. An Afrocentric-postcolonial lens was employed to investigate the factors for its resurgence after decades of absence in the agricultural crop basket. We found that the crop which used to be largely cultivated by women in the past, had become a ‘must-plant’ crop for all gender owing to its high demand on the market, especially in Mozambique.

Vitamin E-Conjugated Phosphopeptide Inhibitor of the Polo-Box Domain of Polo-Like Kinase 1

Polo-like kinase 1 (Plk1) regulates cell cycle and cell proliferation, and is currently considered a potential biomarker in clinical trials for many cancers. A characteristic feature of Plks is their C-terminal polo-box domain (PBD). Pro-Leu-His-Ser-pThr (PLHS[pT])-the phosphopeptide inhibitor of the PBD of Plk1-induces apoptosis in cancer cells. However, because of the low cell membrane-penetration ability of PLHS[pT], new approaches are required to overcome these drawbacks. We therefore developed a vitamin E (VE) conjugate that is biodegradable by intracellular redox enzymes as an anticancer drug-delivery system. To ensure high efficiency of membrane penetration, we synthesized VE-S-S-PLHS[pT]KY (1) by conjugating PLHS[pT] to VE via a disulfide bond. We found that 1 penetrated cancer cell membranes, blocked cancer cell proliferation, and induced apoptosis in cancer cells through cell cycle arrest in the G2/M phase. We synthesized a radiolabeled peptide (124I-1), and the radioligand was evaluated in in vivo tumor uptake using positron emission tomography. This study shows that combination conjugates are an excellent strategy for specifically targeting Plk PBD. These conjugates have a dual function, with possible uses in anticancer therapy and tumor diagnosis.

Study on the influence of palm oil on blood and liver biochemical parameters, beta-carotene and tocochromanols content as well as antioxidant activity in rats

In the ongoing discussion on the health properties of palm oil, a study of the effect a diet supplemented with palm oil on blood and liver biochemical parameters, beta-carotene and tocochromanols content as well as antioxidant activity was undertaken. Forty Wistar rats were randomly divided into five groups, fed with a diet supplemented with plant-based frying commercial fat, palm oil, 7.5% palm oil and 2.5% concentrate from palm oil and 10% of rapeseed oil, respectively. After 21 days, blood samples and livers were collected to determine beta-carotene and tocochromanols concentrations, antioxidant activity using DPPH* radical scavenging activity and TEAC methods, insulin, glucagon, serum triacyloglycerols and cholesterol levels, glucose in blood serum and glycogen in the livers. Research has shown valuable biological properties of palm oil in terms of plasma glucose, total cholesterol, low-density lipoprotein (LDL) cholesterol, and triacylglycerol concentrations which was related to the high content of beta-carotene and tocochromanols. PRACTICAL APPLICATION: Public concern over the health properties of palm oil has been growing. Therefore, this study supplements existing knowledge in this area based on experimental rat observations. In the presented research, plasma glucose was significantly reduced and no additional growth of total or LDL cholesterol, as well as triacylglycerol concentration, was observed after consuming a palm oil-based diet. Palm oil was a good source of beta-carotene and tocochromanols, which were preferentially distributed in rats' livers. Bioavailability of vitamin E-active compounds in palm oil supplemented rats' livers was relatively high as compared to the rapeseed oil group, therefore this observation complements literature in the field of tocotrienols and tocopherols. Studies have not confirmed the harmful effect of palm oil on rats, however in depth human studies appear to be a promising direction for further research.

α-Tocopheryl Succinate Inhibits Osteolytic Bone Metastasis of Breast Cancer by Suppressing Migration of Cancer Cells and Receptor Activator of Nuclear Factor-κB Ligand Expression of Osteoblasts

Background

Breast cancer is one of the most common cancers affecting women and has a high incidence of bone metastasis, causing osteolytic lesions. The elevated expression of receptor activator of nuclear factor-κB ligand (RANKL) in cancer activates osteoclasts, leading to bone destruction. We previously reported that α-tocopheryl succinate (αTP-suc) inhibited interleukin-1-induced RANKL expression in osteoblasts. Here, we examined the effect of αTP-suc on osteolytic bone metastasis in breast cancer.

Methods

To examine the effect of αTP-suc on the metastatic capacity of breast cancer, MDA-MB-231-FL cells were injected into the left cardiac ventricle of BALB/c nude mice along with intraperitoneal injection of αTP-suc. The mice were then analyzed by bioluminescence imaging. To investigate the effect of αTP-suc on osteolysis, 4T1 cells were directly injected into the femur of BALB/c mice along with intraperitoneal injection of αTP-suc. Microcomputed tomography analysis and histomorphometric analysis of the femora were performed.

Results

αTP-suc inhibited cell migration and cell growth of 4T1 cells. In line with these results, bone metastasis of MDA-MB-231-FL cells was reduced in mice injected with αTP-suc. In addition, αTP-suc decreased osteoclastogenesis by inhibiting 4T1-induced RANKL expression in osteoblasts. Consistent with these results, 4T1-induced bone destruction was ameliorated by αTP-suc, with in vivo analysis showing reduced tumor burden and osteoclast numbers.

Conclusions

Our findings suggest that αTP-suc may be efficiently utilized to prevent and treat osteolytic bone metastasis of breast cancer with dual effects.

Recent Advances in the Application of Vitamin E TPGS for Drug Delivery

D-ɑ-tocopheryl polyethylene glycol succinate (Vitamin E TPGS or TPGS) has been approved by FDA as a safe adjuvant and widely used in drug delivery systems. The biological and physicochemical properties of TPGS provide multiple advantages for its applications in drug delivery like high biocompatibility, enhancement of drug solubility, improvement of drug permeation and selective antitumor activity. Notably, TPGS can inhibit the activity of ATP dependent P-glycoprotein and act as a potent excipient for overcoming multi-drug resistance (MDR) in tumor. In this review, we aim to discuss the recent advances of TPGS in drug delivery including TPGS based prodrugs, nitric oxide donor and polymers, and unmodified TPGS based formulations. These potential applications are focused on enhancing delivery efficiency as well as the therapeutic effect of agents, especially on overcoming MDR of tumors. It also demonstrates that the clinical translation of TPGS based nanomedicines is still faced with many challenges, which requires more detailed study on TPGS properties and based delivery system in the future.

Vitamin E: Emerging aspects and new directions

The discovery of vitamin E will have its 100th anniversary in 2022, but we still have more questions than answers regarding the biological functions and the essentiality of vitamin E for human health. Discovered as a factor essential for rat fertility and soon after characterized for its properties of fat-soluble antioxidant, vitamin E was identified to have signaling and gene regulation effects in the 1980s. In the same years the cytochrome P-450 dependent metabolism of vitamin E was characterized and a first series of studies on short-chain carboxyethyl metabolites in the 1990s paved the way to the hypothesis of a biological role for this metabolism alternative to vitamin E catabolism. In the last decade other physiological metabolites of vitamin E have been identified, such as α-tocopheryl phosphate and the long-chain metabolites formed by the ω-hydroxylase activity of cytochrome P-450. Recent findings are consistent with gene regulation and homeostatic roles of these metabolites in different experimental models, such as inflammatory, neuronal and hepatic cells, and in vivo in animal models of acute inflammation. Molecular mechanisms underlying these responses are under investigation in several laboratories and side-glances to research on other fat soluble vitamins may help to move faster in this direction. Other emerging aspects presented in this review paper include novel insights on the mechanisms of reduction of the cardiovascular risk, immunomodulation and antiallergic effects, neuroprotection properties in models of glutamate excitotoxicity and spino-cerebellar damage, hepatoprotection and prevention of liver toxicity by different causes and even therapeutic applications in non-alcoholic steatohepatitis. We here discuss these topics with the aim of stimulating the interest of the scientific community and further research activities that may help to celebrate this anniversary of vitamin E with an in-depth knowledge of its action as vitamin.

ω-3 in meat products: benefits and effects on lipid oxidative stability

Although ω-3 intake has been associated with numerous health benefits, its addition to certain food matrices, and in particular meat products, may involve various technological barriers influencing the final quality of the products. Lipid oxidation must be highlighted due to the modification of both the sensory characteristics and the shelf-life of meat products. In order to reduce the impact of chemical changes and promote oxidative stability, the use of natural antioxidants has gained ground owing to the health and safety advantages linked to its effectiveness at reducing lipid oxidation. Many natural compounds have also been successfully tested in animal feed, in order to protect the raw meat materials and reduce the risk of lipid oxidation in processed products. This review aims to address the challenges and advantages of the incorporation of ω-3 fatty acids in raw meat materials and processed meat products, and to describe the use of different compounds to enhance lipid oxidative stability. © 2015 Society of Chemical Industry.

Quantitative Trait Loci Associated with the Tocochromanol (Vitamin E) Pathway in Barley

The Genome-Wide Association Studies approach was used to detect Quantitative Trait Loci associated with tocochromanol concentrations using a panel of 1,466 barley accessions. All major tocochromanol types- α-, β-, δ-, γ-tocopherol and tocotrienol- were assayed. We found 13 single nucleotide polymorphisms associated with the concentration of one or more of these tocochromanol forms in barley, seven of which were within 2 cM of sequences homologous to cloned genes associated with tocochromanol production in barley and/or other plants. These associations confirmed a prior report based on bi-parental QTL mapping. This knowledge will aid future efforts to better understand the role of tocochromanols in barley, with specific reference to abiotic stress resistance. It will also be useful in developing barley varieties with higher tocochromanol concentrations, although at current recommended daily consumption amounts, barley would not be an effective sole source of vitamin E. However, it could be an important contributor in the context of whole grains in a balanced diet.

Non-targeted1H-NMR-metabolomics suggest the induction of master regulators of energy metabolism in the liver of vitamin E-deficient rats

Consumption of a vitamin E-deficient diet for 6 months may alter hepatic energy metabolism in rats.

Sesame (Sesamum indicum L.)

Sesame (Sesamum indicum L.) is an important oilseed crop grown in India, China, Korea, Russia, Turkey, Mexico, South America, and several countries of Africa. Sesame seeds are rich in oil, proteins, unsaturated fatty acids, vitamins, minerals, and folic acid. Nearly 70% of the world's sesame is processed into oil and meal, while the remainder is channeled to food and confectionery industries. Production of sesame is limited by several fungal diseases, water logging, salinity, and shattering of seed capsules during harvest. Introgression of useful genes from wild species into cultigens by conventional breeding has not been successful due to postfertilization barriers. The only alternative for the improvement of S. indicum is to transfer genes from other sources through genetic transformation techniques. Here, we describe a simple, fast, and reproducible method for the Agrobacterium-mediated genetic transformation of S. indicum which may be employed for the transfer of desirable traits into this economically important oilseed crop.

Vitamin E transporters in cancer therapy

Besides their potent antioxidant activity, vitamin E isoforms demonstrated multiple therapeutic activities among which is their activity against different cancer types, including breast, prostate, and colon cancers. However, the activity of vitamin E isoforms is limited by their low bioavailability following oral administration. In addition to the low solubility, vitamin E isoforms have been established as substrates for several intestinal and hepatic transport proteins. In this review, we present reported anticancer activity of vitamin E family members and the possible utilization of vitamin E and derivatives as chemosensitizers to reverse multidrug resistance when given as part of a delivery system and/or in combination with anticancer therapeutic drugs. Then, the review discusses disposition of vitamin E members and transport proteins that play a role in determining their systemic bioavailability followed by recent advances in vitamin E formulations and delivery strategies.

Vitamin E-based nanomedicines for anti-cancer drug delivery

This review aims to highlight the development of novel vitamin E conjugates for the vectorization of active pharmaceutical ingredients through nanotechnologies. The physico-chemical and biological properties of vitamin E derivatives offer multiple advantages in drug delivery like biocompatibility, improvement of drug solubility and anticancer activity. Nanomedicines have shown high potential in drug delivery since (i) they may offer better drug biopharmaceutical properties such as longer half-life or better bioavailability and (ii) they have shown benefits in cancer therapy by improving anticancer drug therapeutic index. Vitamin E-based nanomedicines were developed to combine the pharmaceutical properties of both vitamin E and nanomedicines for two purposes: (i) to improve water solubility of hydrophobic drugs and (ii) to enhance the therapeutic efficiency of anticancer agents. This review is divided into three parts: the first one describes the biology and the metabolic functions of vitamin E, the second one focuses on the anticancer activity of two vitamin E derivatives: vitamin E succinate (TOS) and vitamin E polyethylene glycol-succinate (TPGS). Finally, in the third part, we discuss vitamin E derivatives based-nanomedicines.

α-Tocopherol transfer protein is not required for the discrimination against γ-tocopherol in vivo but protects it from side-chain degradation in vitro

SCOPE

The mechanisms underlying the preferential retention of a single compound (α-tocopherol (αT)) of the eight vitamin E compounds in the body are incompletely understood. We hypothesized that vitamin E metabolism and not the hepatic α-tocopherol transfer protein (TTP) is responsible for the discrimination against non-αT congeners.

METHODS AND RESULTS

TTP knockout and wild-type mice (n = 12/group) were fed equimolar concentrations of αT and γ-tocopherol (γT; 50 mg/kg diet each) alone or together with sesamin (2 g/kg diet) for 6 wk. Inhibition of vitamin E metabolism with sesamin, but not TTP knockout, increased γT tissue concentrations. TTP-expressing and TTP-free cells were incubated with equimolar concentrations of αT and γT (25 μmol/L each) with or without sesamin (2 μmol/L). The preferential degradation of γT independently of TTP expression was confirmed and a decrease in the production of the metabolite γ-carboxyethyl hydroxychromanol (CEHC) with increasing TTP expression revealed. Displacing γT from TTP in these cells by incubation with increasing αT concentrations enhanced the secretion of γ-CEHC in TTP-transfected cells, suggesting that TTP might protect γT from β-oxidation.

CONCLUSIONS

We conclude that vitamin E metabolism and not TTP controls γT concentrations in vivo and observed an interaction of TTP with vitamin E metabolism that results in reduced production of the metabolite γ-CEHC.

Do tocotrienols have potential as neuroprotective dietary factors?

Tocotrienols (T(3)) belong to the family of vitamin E compounds (α-, β-, γ-, δ-tocopherols and -tocotrienols) and have unique biological properties that make them potential neuroprotective dietary factors. In addition to their antioxidant activity, T(3) at micromolar concentrations exert cholesterol-lowering activities in cells, animal models and some, but not all, human studies by means of inhibition of the activity of the rate-limiting enzyme in cholesterol biosynthesis, 3-hydroxy-3-methylglutaryl coenzyme A reductase. At lower concentrations (∼10 nmol/L), T(3) modulate signalling pathways involved in neuronal cell death in cell culture experiments. Targets of T(3) include prenyl transferases, non-receptor tyrosine kinase, phospholipase A(2), 12-lipoxygenase, cyclooxygenase-2, and nuclear factor κB. The low bioavailability and rapid excretion of T(3) represents a major hurdle in their preventive use. Fasting plasma concentrations, even after supplementation with high doses, are below 1 μmol/L. T(3) bioavailability may be enhanced by ingestion with a high-fat meal, self-emulsifying drug delivery systems, or phytochemicals that inhibit T(3) metabolism and excretion. T(3) have no known adverse effects when consumed as part of a normal diet and the studies reviewed here support the notion that they may have potential as neuroprotective agents. However, experiments in relevant animal models and randomised human intervention trials addressing the neuroprotection mediated by T(3) are scarce and, thus, highly warranted.

Gene-regulatory activity of alpha-tocopherol

Vitamin E is an essential vitamin and a lipid soluble antioxidant, at least, under in vitro conditions. The antioxidant properties of vitamin E are exerted through its phenolic hydroxyl group, which donates hydrogen to peroxyl radicals, resulting in the formation of stable lipid species. Beside an antioxidant role, important cell signalling properties of vitamin E have been described. By using gene chip technology we have identified alpha-tocopherol sensitive molecular targets in vivo including christmas factor (involved in the blood coagulation) and 5alpha-steroid reductase type 1 (catalyzes the conversion of testosterone to 5alpha-dihydrotestosterone) being upregulated and gamma-glutamyl-cysteinyl synthetase (the rate limiting enzyme in GSH synthesis) being downregulated due to alpha-tocopherol deficiency. Alpha-tocopherol regulates signal transduction cascades not only at the mRNA but also at the miRNA level since miRNA 122a (involved in lipid metabolism) and miRNA 125b (involved in inflammation) are downregulated by alpha-tocopherol. Genetic polymorphisms may determine the biological and gene-regulatory activity of alpha-tocopherol. In this context we have recently shown that genes encoding for proteins involved in peripheral alpha-tocopherol transport and degradation are significantly affected by the apoE genotype.

Tocopherol isomer pattern in serum and stool of human following consumption of black currant seed press residue administered in whole grain bread

BACKGROUND & AIMS

Serum gamma-tocopherol is thought to be associated with human health. The dietary influence of tocopherol and fibre-rich black currant seed press residue on serum and stool tocopherol concentration was investigated in a controlled human intervention study.

METHODS

Thirty-six women consumed bread enriched with black currant press residue (4 weeks). The resultant faecal and serum tocopherol concentrations were compared with those after a period consuming control bread without press residue and a normal baseline diet. Fibre intake and excretion, antioxidant capacity (TEAC), and vitamin C concentrations in serum and urine were also determined. Samples were obtained with a 5-day standardised diet at the end of each period.

RESULTS

The press residue bread lead to significantly increased beta-, gamma-, delta- and total tocopherol intake, serum alpha-, beta-, gamma- and total tocopherol concentration (with and without lipid adjustment), fibre intake and urinary vitamin C concentration compared to control bread (P<0.05). Faecal excretion of total tocopherols and fibre increased compared to baseline (P<0.05).

CONCLUSIONS

Fibre intake and excretion influence total tocopherol concentration in lipid-adjusted serum and in stool. The outstandingly high increase of serum gamma-tocopherol concentration through seed press residue consumption could be due to a presumed interruption of the enzymatic tocopherol degradation mechanism by bread constituents.

Dietary flavonoids do not affect vitamin E status in growing rats

This study aimed at investigating potential effects of the flavonoids genistein, quercetin and catechin and the role of co-ingested dietary fat on vitamin E concentrations in rats. In experiment 1, genistein, quercetin and catechin were fed to rats, incorporated into semisynthetic diets at concentrations of 2 g/kg, either as individual compounds or in combination to investigate their individual and possible synergistic actions towards alpha-tocopherol in plasma and selected tissues. For experiments 2 and 3, quercetin was selected as a representative model flavonoid to study the effects of the quantity (5% vs. 10%) and type of dietary fat (coconut fat plus corn oil vs. rapeseed oil; experiment 2) and the role of cholesterol (experiment 3) on potential flavonoid-vitamin E interactions. The concentrations of alpha-tocopherol and gamma-tocopherol in the plasma, liver, lung and cortex of flavonoid-fed rats were not significantly different from the concentrations measured in control rats in all three experiments. However, increasing the amount of coconut fat plus corn oil from 5 to 10% resulted in lower alpha-tocopherol concentrations in plasma and tissue. The alpha-tocopherol concentrations in the rats fed rapeseed oil were significantly higher than in rats fed coconut fat plus corn oil. The addition of 0.2% cholesterol to the diet did not influence the tocopherol concentrations in plasma and tissue in both quercetin-supplemented and control rats. Additionally, the mRNA levels of alpha-TTP, CYP3A4, CYP4F and Mdr2, which are integral proteins involved in vitamin E homeostasis were measured. Only genistein reduced the Mdr2 mRNA level, but none of the other transcripts. All other flavonoids were without effect. In conclusion, co-ingested dietary fat appears to influence vitamin E concentrations in rats, but does not seem to be an important determinant of flavonoid-vitamin E interactions.

A survey of sesamin and composition of tocopherol variability from seeds of eleven diverse sesame (Sesamum indicum L.) genotypes using HPLC-PAD-ECD

The objective of this study was to determine the composition and content of sesamin and desmethyl tocopherols such as alpha-tocopherol (alphaT), delta-tocopherol (deltaT) and gamma-tocopherol (gammaT) in seeds of sesame (Sesamum indicum L.) for 11 genotypes conserved in the United States Department of Agriculture (USDA), Agricultural Research Service (ARS) and Plant Genetic Resources Conservation Unit (PGRCU) in Griffin, Georgia, USA. Seed accessions studied were collections from eight countries worldwide, including one landrace from Thailand and two cultivars from Texas, USA. Novel methodologies and analytical techniques described herein consisted of reverse-phase high-performance liquid chromatography (HPLC) connected in series with two detection systems specific for each analyte class. Photodiode array detection was employed for sesamin analysis and electrochemical array detection was used in the determination of tocopherols. A preliminary study was conducted to assess sesamin levels in 2003 and tocopherol levels in 2004 from sesame seed samples conserved at the USDA, ARS and PGRCU. In 2005, sesame seed samples were grown, harvested and evaluated for sesamin as well as tocopherol levels. The overall results (n = 3) showed that sesamin, alphaT, deltaT and gammaT levels were 0.67-6.35 mg/g, 0.034-0.175 microg/g, 0.44-3.05 microg/g and 56.9-99.3 microg/g respectively, indicating that the sesame seed accessions contained higher levels of sesamin and gammaT compared with alphaT and deltaT. Statistical analysis was conducted and significant differences were observed among the 11 different sesame genotypes. This suggests that genetic, environmental and geographical factors influence sesamin and desmethyl tocopherol content.

Vitamin E Biochemistry and Function: A Case Study in Male Rabbit

Vitamin E supplementation has become a common procedure to promote growth and health and improve the qualitative characteristics of farm animals. It has been demonstrated to be an efficient strategy for improving their reproductive function. Germ cells are particularly vulnerable to oxidative damage and may thus require additional antioxidant protection. The aim of this review is to give a comprehensive overview of the current knowledge of the biochemistry and physiology of vitamin E; successively, the effect of this compound on the reproductive activity of rabbit buck is accurately described. In particular, this review examines studies on the effects of animal age, dose and duration of vitamin E supplementation, as well as the co-supplementation with selenium, vitamin C and polyunsaturated fatty acids. Several investigations have shown beneficial effects in bucks supplemented with vitamin E levels higher than the standard dietary requirement (50 mg/kg) particularly when the semen is stored. However, the exact dietary intake of vitamin E should be decided according to specific tissue needs for the individual vitamin E forms and the specific saturation markers.

Alkylresorcinols from whole-grain wheat and rye are transported in human plasma lipoproteins

Alkylresorcinols with alkyl chains C17:0-C25:0 are abundant in whole-grain wheat and rye. Concentrations in human plasma have been suggested to be biomarkers of dietary whole-grain intake. We measured human plasma, erythrocyte, and lipoprotein alkylresorcinol concentrations and alkylresorcinol homolog distribution, and evaluated the use of plasma alkylresorcinol concentration as a dietary biomarker of whole-grain intake compared with serum enterolactone. A total of 15 subjects (8 women) consumed whole-grain wheat or whole-grain rye crisp bread ( approximately 100 g/d) in a crossover design for 1 wk. The test bread periods were preceded by 1-wk periods of consuming refined wheat bread. Plasma, erythrocyte, lipoprotein alkylresorcinol, and serum enterolactone concentrations were measured before and after each period, and plasma alkylresorcinols and serum enterolactone were measured after habitual diet intake before and 1 wk after the trial. Plasma alkylresorcinols are transported in lipoproteins with VLDL and HDL being the main carriers. AR concentrations in plasma, erythrocytes, and lipoproteins were increased (P < 0.05) by whole-grain wheat bread and even more so with rye crisp bread, although interindividual variation was high. The alkylresorcinol homolog C17:0 to C21:0 ratio in plasma was higher after the whole-grain rye diet period compared with the whole-grain wheat diet period (P < 0.05). Serum enterolactone concentrations were increased significantly by whole-grain rye intake only in men. This is the first report to show that alkylresorcinols in human plasma are mainly transported in lipoproteins. The plasma alkylresorcinol C17:0 to C21:0 ratio reflects intake of whole-grain wheat and rye, and the plasma total alkylresorcinol concentration appears to be a useful biomarker of whole-grain cereal intake.

Effect of Dietary Grape Pomace and Vitamin E on Growth Performance, Nutrient Digestibility, and Susceptibility to Meat Lipid Oxidation in Chickens

Grape pomace (GP) is a source of polyphenols with powerful antioxidant capacity. An experiment was conducted to investigate the effect of inclusion of GP at levels of 5, 15, and 30 g/kg and alpha-tocopheryl acetate (200 mg/kg) in a corn-soybean basal diet on growth performance, protein and amino acid digestibilities; antioxidant activity of diet, serum and excreta, lipid oxidation of breast and thigh meats during refrigerated storage, and liver vitamin E concentration. Growth performance and protein and amino acid digestibilities were not affected among the different treatments. Total intake and digestibility of extractable polyphenols in the birds fed the GP diet were increased compared with birds fed supplemented and unsupplemented vitamin E diets. Antioxidant activity in vitamin E and GP diets and excreta exhibited higher scavenging free radical capacity than the control diet using 3-ethylbenzthiazoline-6-sulfonic acid and ferric reducing antioxidant power methods. Lipid oxidation (malondialdehyde concentration) in breast and thigh meats was lower in the birds fed the supplemented vitamin E diet than the control diet after 1, 4, and 7 d of refrigerated storage. Results showed a linear reduction of lipid oxidation in breast and thigh meats at 4 and 7 d with increasing content of GP in the diet. Oxidative stability in breast and thigh meats at 1, 4, and 7 d of storage was equivalent or less effective in GP diets compared with the vitamin E diet. A linear increase was observed in liver alpha-tocopherol concentration with increasing content of GP in the diet, but it was inferior to the supplemented vitamin E diet. In conclusion, the results showed that a dietary inclusion rate up to 30 g/kg of GP did not impair chickens growth performance and protein and amino acids digestibilities and increased antioxidant activity in diet and excreta. Grape pomace and vitamin E diets reduced the lipid oxidation of meat during refrigerated storage and increased liver alpha-tocopherol concentration, although these effects were greater, in some cases, by adding vitamin E to the diet.

Vitamin E Biotransformation in Humans

The presence and activity of vitamin E in the organism as well as its role in disease prevention depend, as for any other microconstituent in food, on a number of factors related to its release from the food matrix, extent of absorption, and metabolic fate. Biotransformation can be defined as the sum of processes in which vitamin E compounds are altered by the body. It involves the bioactivation and production of reactive metabolites, a series of processes generally referred to as "vitamin E metabolism." This chapter will provide an overview of the known and less known steps of vitamin E biotransformation in humans. Due to recent advances related to the biological activities and metabolic processing of vitamin E compounds, particular attention will be given to the description of the formation, identification, and functions of vitamin E metabolites. The hypothesis of a transformation-dependent bioactivation of vitamin E represents an intriguing and emerging aspect of research that deserves further investigation.

Influence of dietary antioxidants on polyphenol intestinal absorption and metabolism in rats

The ingestion of complex foodstuff implicates the simultaneous presence along the digestive tract of several antioxidants micronutrients. This work aimed to determine if the interactions that may occur at the digestive level between polyphenols and other antioxidant micronutrients may modulate the fate of polyphenols in the splanchnic area. This study was conducted in a rat in situ intestinal perfusion model. Polyphenols (gallic and caffeic acids, catechin, and naringenin) were perfused with or without an antioxidant cocktail. For gallic acid, a significant reduction (-20%) of its net transfer through the brush border associated with a drastic decrease of its intestinal secretion of conjugates (-90%) was observed. By contrast, the transfer of catechin through the brush border increased (18%) and the secretion of its conjugates was twice in the presence of the antioxidants. Perfused polyphenols largely differed in their respective biliary secretion, but these fluxes were not modified by the presence of the antioxidant cocktail. Finally, the simultaneous presence in the small intestine of polyphenols and other dietary antioxidants never affects polyphenol splanchnic metabolism but may modify their intestinal transport without noticeable consequence on their final availability for peripheral tissues.