Search Results (153)

Retinol and retinol-related compounds are essential for human health, particularly in cellular protection, skin health, and the management of medical conditions. Retinol—a vital form of vitamin A—is obtained through the diet as preformed vitamin A or provitamin A carotenoids, retinyl esters. These compounds are indispensable for vision, immune function, and skin health. While retinoic acid has important known biological roles, its presence is limited in the body as it is rapidly metabolized rather than stored, emphasizing the need for sufficient dietary intake. This paper is divided into chapters that highlight important aspects of retinol and retinoid-related compounds, such as their sufficient intake through food sources. The nutritional value of carotenoids is influenced by the balance between trans- and cis-isomers in food, with food processing affecting their bioactivity. Next, it is metabolism in the digestive tract. The bioavailability and efficacy of retinoids are further influenced by gut microbiota, which can modulate immune function and the expression of the genes involved in retinoid metabolism. A third important property greatly influencing their biological function is their structure, predisposing them to certain biological activities. Both retinoids and carotenoids exert key antioxidant functions by protecting cells from oxidative damage, quenching singlet oxygen, and stabilizing free radicals. However, the oxidation of carotenoids can result in various metabolites, such as epoxides and hydroxyketones, that further create a higher demand for antioxidant defenses. Additionally, carotenoids interact with lipoxygenases (LOXs), thus influencing oxidative stress, although this interaction may reduce their antioxidant efficacy. First- and second-generation retinoids regulate gene expression related to skin cell function and oncological diseases. Despite their therapeutic benefits, long-term use carries risks, such as teratogenicity. Ongoing research should aim to enhance the safety, precision, and effectiveness of retinoid therapies, expanding their therapeutic potential. Full article

Micronutrient deficiencies and the increased incidences of non-communicable diseases are public health challenges for the sub-Saharan population. Leafy vegetables reportedly contain several minerals, vitamins and antioxidant compounds which could help reduce the above challenges. However, overall vegetable consumption is still low in Uganda, partly due to limited information about the nutritional quality and health-promoting properties of the available vegetable species. To provide scientific justification for increased growth/production and utilisation of specific leafy vegetable species as food, the nutrient and phytochemical compositions were determined in nine African leafy vegetables. The ‘true’ protein and dietary fibre contents were 13–33 and 29–43 g/100 g DW, respectively, whereas the starch content was below 6 g/100 g DW. As for the minerals, the Ca, Mg, and Fe contents were 630–3395, 324–1428, and 14–78 mg/100 g DW, respectively, whereas the Zn content was below 6 mg/100 g DW. High carotenoid contents were observed with lutein and β-carotene as the predominant carotenoids (25–60 and 12–29 mg/100 g DW, respectively). The vitamin C and total polyphenol contents were 24–253 mg/100 g DW and 17–43 mg GAE/g DW, respectively. The leafy vegetables studied are low-calorie and can be considered alternative protein sources. They are generally health-beneficial foods as they contain natural antioxidant compounds, vitamin C, carotenoids and polyphenols. African nightshade, Amaranthus sp., cowpea leaves, and spider plant are potential sources of provitamin A (β-carotene) and minerals (Ca and Fe); hence, they can help reduce incidences of related deficiencies. Full article

The bioaccessibility (fraction of compounds released from the food matrix and available for absorption) and carotenoid content of carrot chromoplasts obtained through high-speed centrifugation using sucrose gradients were assessed. Three chromoplast bands were isolated, corresponding to sucrose gradients between 15 and 30%, 30 and 40%, and 40 and 50%. Total carotenoid levels increased ~2.8-fold when comparing the fractions of the bands of the lowest and highest sucrose gradients. The carotenoid profiles of the bands were similar. Phytoene and phytofluene accounted for approximately 3 and 4%, respectively, while ζ-carotene made up about 3%. Provitamin A carotenoids comprised about 85% of the total carotenoids in the respective fractions. Lutein content varied among fractions, with 1.61% in the 15/30% band and 0.77% in the 40/50% sucrose band. Similar micellar carotenoid profiles were also observed across fractions. α-carotene and β-carotene accounted for 8% and 0.2% of the total carotenoid content, respectively, while ζ-carotene constituted 19%. Lutein content in micelles ranged from 0.5% in the highest sucrose content fractions to 3.2% in the lowest. Phytoene and phytofluene were the predominant carotenoids in micelles. They accounted for 41.7% and 28.4%, respectively, together representing 70% of all carotenoids, with no differences among fractions. Colourless carotenoids were more readily incorporated into micelles, followed by ζ-carotene, lutein, and provitamin A carotenoids. Full article

Biological sex is a fundamental determinant of physiological differences, including metabolic processes and disease susceptibility. β-carotene (BC), a provitamin A carotenoid, is known for its health benefits, but its sex-specific effects on its metabolism remain largely unexplored. This study investigated male and female BALB/c mice receiving BC or vehicle control via oral gavage for 11 weeks. Hepatic and circulating lipid levels, serum retinol, and the expression of BC cleavage enzymes (Bco1 and Bco2) and estrogen receptors (Esr1 and Esr2) in the liver and gonadal fat were analyzed. BC supplementation increased the hepatic Bco1 and Bco2 expression in males, accompanied by higher serum retinol, while downregulating expressions of these enzymes in male gonadal fat. Additionally, BC supplementation significantly reduced gonadal fat mass and adipogenic gene expression in males, with Cebpa and Esr1/Esr2 positively correlated, suggesting a role for estrogen receptor signaling in adipogenesis. These findings demonstrate that BC exerts sex- and tissue-specific effects on lipid metabolism, with strong regulatory interactions between BC metabolism, lipid homeostasis, and sex hormone signaling in males. The results provide novel insights into the mechanisms underlying sex-dependent differences in lipid metabolism following BC supplementation, with potential implications for metabolic health and disease prevention. Full article

Plant-based diets are associated with numerous health benefits, including reduced risks of chronic diseases. However, questions persist regarding the implications of lower dietary intakes of certain non-essential nutrients, such as retinol, vitamin K2, carnitine, and creatine, which are primarily found in animal-derived foods. This narrative review evaluates the roles of these nutrients in human physiology and examines whether their absence in plant-based diets is likely to impact health outcomes. Retinol requirements can be met through the consumption of provitamin A carotenoids in plant foods, even in individuals with reduced conversion efficiency. Endogenous synthesis adequately supports physiological needs for vitamin K2, and currently available evidence does not consistently demonstrate that dietary vitamin K2 provides additional benefits for bone or cardiovascular health. Carnitine and creatine levels may differ between individuals following omnivorous and plant-based diets, but these differences do not result in compromised muscle function, cognitive health, or metabolic outcomes. Current evidence does not indicate that the absence of these non-essential nutrients in plant-based diets adversely affects health or confers disadvantages compared to omnivorous diets. Full article

The aim of this study was to determine the retention of fatty acids, α-tocopherol, and carotenoids in sea buckthorn oil (SBO) encapsulated with gum arabic (GA), β-cyclodextrin (β-CD), and their mixture (1:1) under pre-optimized spray drying conditions in comparison to the bioactive molecule (BAM) content of the non-encapsulated oil. In addition, the color parameters in the spray-dried powders and the bioaccessibility of β-carotene, which has the highest provitamin A activity, were evaluated. The fatty acid content remained almost unchanged, while statistically significant differences in α-tocopherol and carotenoid content were found between the SBO encapsulated with different carriers and the non-encapsulated oil. The retention of tocopherols and carotenoids compared to the non-encapsulated SBO ranged from 62.13 to 87.23% and from 21.17 to 97.61%, respectively. SBO encapsulated with β-CD showed significantly higher retention of α-tocopherol (87.23%) and individual carotenoids (40.71–97.61%). In addition, the powders showed no significant differences in color parameters, and the powders encapsulated with GA and β-CD showed high bioaccessibility of β-carotene (92.50 and 90.45%, respectively). β-CD proved to be the most suitable carrier for the encapsulation of the carotenoids and α-tocopherol of SBO, resulting in powders with high bioaccessibility of β-carotene. Full article

Traditional maize possesses low concentrations of provitamin-A and vitamin-E, leading to various health concerns. Mutant alleles of crtRB1 and vte4 that enhance β-carotene (provitamin-A) and α-tocopherol (vitamin-E), respectively, in maize kernels have been explored in several biofortification programs. For genetic improvement of these target nutrients, uniplex-PCR assays are routinely used in marker-assisted selection. However, due to back-to-back breeding seasons, the time required for genotyping individually for each target gene in large backcross populations becomes a constraint for advancing the generations. Additionally, multiple PCR assays for various genes increase the required costs and resources. Here, we aimed to develop a multiplex-PCR assay to simultaneously identify different allelic forms of crtRB1 and vte4 genes and validate them in a backcross-based segregating population. The PCR assay was carried out using newly developed primers for crtRB1 and a gene-specific primer for vte4. The uniplex-PCR assay was standardized for selected primer pairs in the BC₁F₁ population segregating for crtRB1 and vte4 genes. Subsequently, a multiplex-PCR assay for crtRB1 and vte4 genes was developed and employed for genotyping in the BC₁F₁ population. The assay differentiated among four possible genotypic classes, namely crtRB1⁺crtRB1/vte4⁺vte4, crtRB1crtRB1/vte4⁺vte4, crtRB1⁺crtRB1/vte4⁺vte4⁺, and crtRB1crtRB1/vte4⁺vte4⁺. This newly developed multiplex-PCR assay saved 41.7% of the cost and 35.6% of the time compared to two individual uniplex-PCR assays. The developed assay could accelerate maize nutritional quality breeding programs through rapid and cost-effective genotyping for the target genes. This is the first report of a multiplex-PCR assay specific to crtRB1 and vte4 genes for its use in genomics-assisted breeding in maize. Full article

The aim of this research was to design and synthesize new lipid conjugates of 7-DHC that could serve as a new storage form of esterified provitamin D₃, increasing the reservoir of this biomolecule in the epidermis and enabling controlled production of vitamin D₃ even during periods of sunlight deficiency. Acylglycerol and glycerophospholipid containing succinate-linked provitamin D₃ at the sn-2 position of the glycerol backbone were synthesized from dihydroxyacetone (DHA) and sn-glycerophosphocholine (GPC), respectively. The three-step synthesis of 1,3-dipalmitoyl-2-(7-dehydrocholesterylsuccinoyl)glycerol involved the esterification of DHA with palmitic acid, reduction of the carbonyl group, and conjugation of the resulting 1,3-dipalmitoylglycerol with 7-dehydrocholesterol hemisuccinate (7-DHC HS). The use of NaBH₃CN as a reducing agent was crucial to avoid acyl migration and achieve the final product with 100% regioisomeric purity. For the preparation of 1-palmitoyl-2-(7-dehydrocholesterylsuccinoyl)-sn-glycero-3-phosphocholine, a two-step process was applied, involving the esterification of GPC at the sn-1 position with palmitic acid, followed by the conjugation of 1-palmitoyl-sn-glycero-3-phosphocholine with 7-DHC HS. Alongside the main product, a small amount of its regioisomer with provitamin D₃ linked at the sn-1 position and palmitic acid at the sn-2 position was detected, indicating acyl migration from the sn-1 to the sn-2 position in the intermediate 1-palmitoyl-sn-glycerophosphocholine. The synthesized novel lipids were fully characterized using spectroscopic methods. They can find applications as novel lipid-based prodrugs as additives to sunscreen creams. Full article

Background: A new vitamin concept, termed vitamin A5, an umbrella term for vitamin A derivatives being direct nutritional precursors for 9-cis-13,14-dihydroretinoic acid and further induction of RXR-signaling, was recently identified with global importance for mental health and healthy brain and nerve functions. Dietary recommendations in the range of 1.1 (0.5–1.8) mg vitamin A5 / day were suggested by an international expert consortium. The ensuing question arises as to the current daily dietary intake amounts in Western civilization. Methods: Addressing this answer included calculating the intake based on known amounts of vitamin A5 in frequently consumed food items of the human diet that are high in this vitamin, as well as the known daily dietary intake amounts of those selected food components in Westernized countries. Results: Regarding food items, amounts of vitamin A5 in the form of provitamin A5 (i.e., 9-cis-beta-carotene (9CBC)), the predominant form in the diet, were found to range from 0.1 to 39 µg 9CBC / g for individual fruits and vegetables, with the highest concentrations being in leafy vegetables. The average intake amounts of vitamin A5 in adults of the general population following a Western lifestyle in Europe averaged 0.9, with a range from 0.5 (for Austria) to 1.3 (for Italy) mg 9CBC/day. Furthermore, based on our calculations, large parts, i.e., approximately two-thirds, of the population are low, even too low (<1.1 mg/day), in daily vitamin A5 intake. Conclusion: In addition to the importance of nudging the population toward a regrettably non-well-accepted higher intake of fruits and vegetables, an additional fortification and supplementation of vitamin A5 could be considered, similar to other micronutrients that are low in a Westernized diet. Full article

Background: Childhood vitamin A deficiency leads to increased morbidity and mortality. Human milk is the only source of vitamin A for exclusively breastfed infants. Dried Moringa oleifera leaf powder (moringa) is a good food source of provitamin A and other carotenoids. Its effect during lactation on human milk vitamin A and carotenoid content is unclear. Objectives: Our objective was to investigate the effect of maternal moringa consumption on human milk retinol and carotenoid concentrations and maternal and infant vitamin A status. Methods: We conducted a 3-month pilot single-blinded cluster-randomized controlled trial in breastfeeding mother–infant pairs (n = 50) in Kenya. Mothers received corn porridge with (20 g/d) or without moringa with complete breast expressions and maternal and infant serum collected at enrollment (infant <30 days old) and 3 months. Milk was analyzed for retinol and selected carotenoids; maternal/infant serum was analyzed for retinol binding protein (RBP). Results: 88% (n = 44) pairs completed milk and serum samples. Four mothers (9%) had vitamin A deficiency (RBP <0.07 µmol/L); 11 (25%) were vitamin A insufficient (VAI; RBP <1.05 µmol/L). Alpha-carotene concentration in milk was higher in the moringa than the control group at baseline (p = 0.024) and at exit (least squares means, LSM, 95%CI µg/mL 0.003, 0.003–0.004 moringa vs. 0.002, 0.001–0.003 control, n = 22/cluster; p = 0.014). In mothers with VAI, alpha-carotene was higher in the moringa group than controls at exit (LSM, 95%CI µg/mL 0.005, 0.003–0.009 moringa, n = 3, vs. 0.002, 0.000–0.004 control, n = 8, p = 0.027) with no difference at baseline. Milk carotenoids did not correlate with vitamin A status (serum RBP) in infants or mothers. Conclusions: Maternal moringa consumption did not impact concentration of milk vitamin A and resulted in limited increase in milk carotenoids in this cohort. Full article

Plant oils are currently not only an essential element of the healthy eating pyramid, but also a valuable cosmetic material, which, in line with the eco-friendly trends of recent years, is effectively replacing petroleum-derived fatty ingredients. The fatty acids, phenolic compounds, pigments, and vitamins (e.g., A and E) present in plant oils contribute to their health-promoting properties, including antioxidant activity. This study assessed the contents of carotenoids and chlorophylls, as well as the antioxidant properties of 10 selected plant oils. Fenugreek seed oil was shown to have the highest total content of carotenoids, and the most β-carotene. Chokeberry and rosehip oils also contained large amounts of provitamin A, in comparison to the other oils tested. Lycopene was the dominant compound in black currant and rosehip seed oils. Among chlorophyll pigments, elderberry oil had the highest content of chlorophyll a, while black currant oil had large amounts of both chlorophyll a and chlorophyll b. The antioxidant properties of the cold pressed oils obtained from selected seeds and fruit stones, assessed by electron paramagnetic resonance (EPR) spectroscopy as the ability to interact with the DPPH (2,2-diphenyl-1-picrylhydrazyl) free radical, can be ranked as follows: pomegranate > fenugreek > poppy > black currant > chokeberry > rosehip > perilla > elderberry > carrot > fig. The results of this study showed that these plant oils are valuable natural materials with antioxidant properties, which can be an important complement to synthetic antioxidants due to their additional skin care properties. Full article

Carotenoid-rich foods such as citrus fruits have a wide range of functions in human health. They primarily exert antioxidant effects, but individual carotenoids may also act through other health-promoting mechanisms such as β-carotene as pro-vitamin A. Here, we show that red-fleshed sweet oranges grown in tropical climates are 4–9 times richer in carotenoids than their orange-fleshed counterparts, regardless of their maturation stage. The most significant difference observed between both varieties was the presence of lycopene at moderate concentrations (around 8 µg/g FW) in the mature pulp of the red varieties, which was absent in the blond ones. This is because the red-fleshed sweet oranges grown in tropical climates with high temperatures increase lycopene and β-carotene concentrations in their pulp during fruit maturation. Due to lycopene accumulation, red orange juice offers a promising addition to popular blond-orange, with the new varieties Carrancas and Pinhal being perfectly suitable for blending to enhance juice colour. Sao Paulo, one of the world’s leading citrus orange juice producers, as well as other tropical citrus regions could benefit from cultivating using such lycopene-rich cultivars and industrially. Full article

Animal health is affected during heat stress as a result of impaired immune responses, increased production of reactive oxygen species, and/or a deficiency of antioxidants. This leads to an imbalance between oxidants and antioxidants and results in oxidative stress. Heat stress is usually measured in dairy cattle via the temperature-humidity index (THI). In the present study, we aimed at assessing the influence of incremental THI on the balance between oxidative markers and the antioxidant defence system in the plasma of Modicana cows. Twenty-four multiparous, mid-lactating dairy cows were divided into two groups on the basis of different levels of mean THI reached in the period of the previous week up until the day of blood and milk sampling (April THI₁:55, May THI₂:68, June THI₃:71, July THI₄:80). The blood samples were collected to measure reactive oxygen metabolites (ROM) and antioxidant defense markers (ferric reducing ability of plasma (FRAP), paraoxonase (PON), advanced oxidation protein products (AOPP), plasma thiol groups (SHp), as well as lipid-soluble antioxidant pro-vitamin (β-carotene) and vitamins (tocopherol and retinol). Milk characteristics, haematological values, and plasma biochemical metabolites were also evaluated. Results showed a significant increase in ROM (p < 0.05) and a significant decrease in PON (p < 0.05), AOPP (p < 0.05), and β-carotene (p < 0.001). Incremental THI significantly decreased levels of milk fat content, red and white blood cells, plasma glucose, and non-esterified fatty acids, while significantly increasing monocytes and the concentrations of β-hydroxybutyrate and creatinine, but not fructosamine. The results of the study show that heat stress significantly affects reactive oxygen species production and antioxidant parameters. Carotenoid supplementation should be considered to alleviate the impact of these effects. Full article

Vitamin A, an essential micronutrient, is integral to various biological processes crucial for organismal development and maintenance. Dietary sources of vitamin A encompass preformed retinol, retinyl esters, and provitamin A carotenoids. Retinoic acid (RA), a key component, plays pivotal roles in vision, cell proliferation, apoptosis, immune function, and gene regulation. Drug repurposing, an effective strategy for identifying new therapeutic applications for existing drugs, has gained prominence in recent years. This review seeks to provide a comprehensive overview of the current research landscape surrounding retinoids and drug repurposing. The scope of this review encompasses a comprehensive examination of retinoids and their potential for repurposing in various therapeutic contexts. Despite their efficacy in treating dermatological conditions, concerns about toxicity persist, driving the search for safer and more potent retinoids. The molecular mechanisms underlying retinoid activity involve binding to retinoic acid receptors (RARs) and retinoid X receptors (RXRs), leading to transcriptional regulation of target genes. This review seeks to shed light on the possibilities for repurposing retinoids to cover a wider spectrum of therapeutic uses by exploring recent scientific progress. It also aims to offer a more comprehensive understanding of the therapeutic prospects of retinoids and the broader impact of drug repositioning in contemporary medicine. Full article

As more and more consumers are becoming conscious of the safety and taste of meat products, the use of natural additives and innovative processing techniques has gained significant attention. Naturally fermented fruit vinegar is rich in organic acids and antioxidant phenolic compounds. In addition, it contains amino acids, minerals, vitamins, and provitamin beta-carotene, and the presence of acetic acid bacteria may have a positive effect on consumer health. The study aimed to assess the impact of different concentrations of apple vinegar addition on the quality of cooked sausage, focusing on physicochemical parameters, including fatty acid profile and oxidative stability, as well as microbiological quality and sensory changes after production and during chilling storage. Four variants of sausage were prepared: C—sausage without apple vinegar; V1—sausage with 1% of apple vinegar; V3—sausage with 3% of apple vinegar; and V5—sausage with 5% of apple vinegar. All of the tests were carried out after production, as well as after 7 and 14 days of refrigeration storage. The addition of apple vinegar decreased the pH value and increased the oxidation-reduction potential and lipid oxidation in the samples V1, V3, and V5. The sausage with the 5% addition of apple vinegar (V5) was characterized by significantly more intensive brightness (parameter L* = 54.67) in comparison to the C sample (parameter L* = 52.78). The sausages that were tested showed good microbiological quality concerning the total number of microorganisms, lactic acid bacteria, and the absence of pathogenic bacteria. The addition of apple vinegar contributed to the reduction in the intensity of the cured meat flavor and the fatty flavor. Therefore, according to the results presented in this work, it can be concluded that 3% of vinegar is the optimal addition, which may be used in the next step of investigation, taking into account color formation abilities as well as microbiological quality and lipid oxidation processes. Full article