Free radical scavenging properties of phytofluene and phytoene isomers as compared to lycopene: a combined experimental and theoretical study

Microbial upcycling of methane to phytoene using metabolically engineered Methylocystis sp. MJC1 strain

Methane, a potent greenhouse gas, requires sustainable mitigation strategies. Here, the microbial upcycling of methane to phytoene, a valuable colorless carotenoid with applications in the cosmeceutical industry was demonstrated. To achieve this goal, a stepwise metabolic engineering approach was employed in Methylocystis sp. MJC1, a methane-oxidizing bacterium. The incorporation of crtE and crtB genes from Deinococcus radiodurans R1 established the phytoene biosynthetic pathway. This pathway was fine-tuned through promoter optimization, resulting in a phytoene production of 450 μg/L from 37 mmol/L methane. Disrupting the ackA gene reduced a by-product, acetate, by 50 % and increased phytoene production by 56 %. Furthermore, overexpressing the dxs gene boosted phytoene titer 3-fold. The optimized strain produced 15 mg/L phytoene from 2 mol/L methane in fed-batch fermentation, a 4-fold increase in phytoene titer and 4-fold in yield. This demonstrates Methylocystis sp. MJC1's potential for efficient phytoene production and presents a novel approach for greenhouse gas reduction.

Sustainable extraction methods of carotenoids from mango (Mangifera indica L. 'Kent') pulp: Ultrasound assisted extraction and green solvents

Mango is a good source of carotenoids for use in food, cosmetic, and pharmaceutical products because of their organoleptic and health-promoting properties. Safe and sustainable methods for their extraction is required. The present investigation was aimed to study concentration and carotenoid profile of 'Kent' mango pulp through a conventional extraction (CE) and ultrasound-assisted extraction (UAE) using traditional solvents (tetrahydrofuran-THF and diethyl ether: petroleum ether-DE:PE) and green solvents (GS) (2-metiltetrahydrofuran, 2 m-THF; cyclopentyl methyl ether, CPME). Mango showed (μg/g d.w.) β-carotene (29.4), zeaxanthin (1.28), β-cryptoxanthin (2.8), phytoene (18.68) and phytofluene (7.45) in a CE using DE:PE. Similar results were obtained applying DE:PE in UAE and GS in a CE, so CPME and 2-mTHF seem suitable solvents to replace DE:PE in CE. The yield of total carotenes, xanthophylls and carotenoids using GS combined with UAE was lower than with CE, but important enough to be used as a sustainable procedure for obtaining carotenoids from mango pulp.

Lycopene as a Therapeutic Agent against Aflatoxin B1-Related Toxicity: Mechanistic Insights and Future Directions

Aflatoxin (AFT) contamination poses a significant global public health and safety concern, prompting widespread apprehension. Of the various AFTs, aflatoxin B1 (AFB1) stands out for its pronounced toxicity and its association with a spectrum of chronic ailments, including cardiovascular disease, neurodegenerative disorders, and cancer. Lycopene, a lipid-soluble natural carotenoid, has emerged as a potential mitigator of the deleterious effects induced by AFB1 exposure, spanning cardiac injury, hepatotoxicity, nephrotoxicity, intestinal damage, and reproductive impairment. This protective mechanism operates by reducing oxidative stress, inflammation, and lipid peroxidation, and activating the mitochondrial apoptotic pathway, facilitating the activation of mitochondrial biogenesis, the endogenous antioxidant system, and the nuclear factor erythroid 2-related factor 2 (Nrf2)/kelch-like ECH-associated protein 1 (KEAP1) and peroxisome proliferator-activated receptor-γ coactivator-1 (PGC-1) pathways, as well as regulating the activities of cytochrome P450 (CYP450) enzymes. This review provides an overview of the protective effects of lycopene against AFB1 exposure-induced toxicity and the underlying molecular mechanisms. Furthermore, it explores the safety profile and potential clinical applications of lycopene. The present review underscores lycopene's potential as a promising detoxification agent against AFB1 exposure, with the intent to stimulate further research and practical utilization in this domain.

Nutritional and functional insight into novel probiotic lycopene-soy milk by genome edited Bacillus subtilis

Nutritional and functional soy-based milk gains growing attention globally in food industry. However, its poor sensorial attributes, single flavor, and limited substance variety become critical issues in displaying balanced nutrition and multifunction for health. Herein, a novel probiotic lycopene-soy milk was developed by genome edited Bacillus subtilis harboring lycopene biosynthesis cassette with efficient lycopene production of 25.73 ± 1.57 mg/g DCW. Further investigation displayed desirable pH, reducing sugar, protein, total phenolic content and isoflavone for achieved milk than conventional soy milk, implying it with well-balanced nutritional quality. Notably, achieved milk exhibited stronger antioxidant capacity and higher isoflavone bioavailability for functionality. Moreover, it possessed significantly high scores for taste, appearance, and overall acceptability, suggesting its excellent sensorial attributes. To our delight, it is the first time to fortify soy-milk with probiotic and lycopene by genome edited B. subtilis to explore additive effect on improving nutritional value and functionality for food application.

Antioxidant Interactions between Citrus Fruit Carotenoids and Ascorbic Acid in New Models of Animal Cell Membranes

The regular consumption of citrus fruits by humans has been associated with lower incidence of chronic-degenerative diseases, especially those mediated by free radicals. Most of the health-promoting properties of citrus fruits derive from their antioxidant content of carotenoids and ascorbic acid (ASC). In the current work we have investigated the scavenging (against hydroxyl radical) and quenching capacities (against singlet oxygen) of four different carotenoid extracts of citrus fruits in the presence or absence of ASC (μM range) in organic solvent, aqueous solution, micelles and in an innovative biomimicking liposomal system of animal cell membrane (AML). The fruits of four varieties of citrus were selected for their distinctive carotenoid composition (liquid chromatography characterization): 'Nadorcott' mandarin and the sweet oranges 'Valencia late', 'Ruby Valencia' and 'Pinalate' mutant. The quenching activity of citrus carotenoids strongly depended on the biological assemblage: freely diffusible in organic solvent, 'Ruby Valencia' carotenoids (containing lycopene) showed the highest quenching activity, whereas 'Nadorcott' mandarin extracts, rich in β-cryptoxanthin, prevailed in micellar systems. Interestingly, the addition of 10 μM ASC significantly increased the quenching activity of all citrus extracts in micelles: 'Valencia' orange (+53%), 'Pinalate' (+87%), 'Ruby' (4-fold higher) and 'Nadorcott' mandarins (+20%). Accurate C11-BODIPY581/591 fluorescence assays showed solid scavenging activities of all citrus extracts against AML oxidation: 'Valencia' (-61%), 'Pinalate' (-58%) and 'Ruby' oranges (-29%), and 'Nadorcott' mandarins (-70%). Indeed, all four citrus extracts tested here have balanced antioxidant properties; extracts from the 'Nadorcott' mandarin slightly prevailed overall, due, at least in part, to its high content of β-cryptoxanthin. This study depicts some of the antioxidant interactions between citrus fruit carotenoids and ascorbic acid in models of animal cell membranes and reinforces the contribution of them in promoting health benefits for humans.

Development of a novel functional yogurt rich in lycopene by Bacillus subtilis

Functional lycopene-rich yogurt displays attractive nutritious and health-promoting benefits among existing functional dairy products, owing to supplement with lycopene which could enhance immunity, prevent cancer, and cardiovascular diseases. Due to poor stability and fat-solubility of lycopene, its incorporation into yogurt is challengeable. In this study, carotenoid genes for lycopene synthesis were co-introduced into probiotic Bacillus subtilis for efficient lycopene production. Further engineered B. subtilis was applied as adjunct starter culture for achieving lycopene-rich yogurt. Developed yogurt exhibited desirable physiochemical characteristics compared with plain yogurt. Moreover, lycopene-rich yogurt was endowed with significantly high antioxidant capacity. More importantly, this functionalized yogurt had attractive sensorial attributes for quality-assured food to facilitate consumer acceptance. As the first report of fortifying yogurt of lycopene using B. subtilis with improved functional properties, this study offers a new and facile clue to enrich bioactive lycopene and probiotic B. subtilis in yogurt for healthy and nutritional food development.

Juices and By-Products of Red-Fleshed Sweet Oranges: Assessment of Bioactive and Nutritional Compounds

The content of nutrients and bioactive compounds, and antioxidant capacity were assessed in the juices from two red-fleshed oranges, Cara Cara and Kirkwood, and compared with that of a standard Navel orange. Two juice extraction procedures, hand-squeezing and industrial, and two treatments, pasteurization (85 °C/30 s) and high-pressure homogenization (HPH, 150 MPa/55 °C/1 min), were evaluated. For most of the nutrients and bioactive compounds, the hand and industrial juice squeezing rendered similar extraction efficiency. Individual composition of carotenoids in the juices were differentially affected by the extraction procedure and the treatments, but the red-fleshed orange juices contained between 3- to 6-times higher total carotenoids than the standard Navel juices, being phytoene and phytofluene the main carotenoids. The industrial and treated juices of both red-fleshed oranges contained 20-30% higher amounts of tocopherols but about 20% lower levels of vitamin C than Navel juices. Navel juices exhibited higher hydrophilic antioxidant capacity, while the red-fleshed orange juices showed an improved lipophilic antioxidant capacity. The main distinctive characteristic of the industrial juice by-product of the red-fleshed oranges was a higher content of carotenoids (×10) and singlet oxygen antioxidant capacity (×1.5-2) than the Navel by-product.

Technological advances in the production of carotenoids and their applications- A critical review

Carotenoids are naturally occurring pigments that are widely distributed in algae, fungi, bacteria, and plants. Carotenoids play a significant role in the food, feed, cosmetic, nutraceutical, and pharmaceutical industries. These pigments are effectively considered as a health-promoting compounds, which are widely used in our daily diet to reduce the risk of chronic diseases such as cardiovascular diseases, cancer, acute lung injury, cataracts, neural disorders, etc. In this context, this review paper demonstrates the synthesis of carotenoids and their potential application in the food and pharmaceutical industries. However, the demand for carotenoid production is increasing overtime, and the extraction and production are expensive and technically challenging. The recent developments in carotenoid biosynthesis, and key challenges, bottlenecks, and future perspectives were also discussed to enhance the circular bioeconomy.

The Interindividual Variability of Phytofluene Bioavailability is Associated with a Combination of Single Nucleotide Polymorphisms

SCOPE

Phytofluene is a colorless carotenoid with potential health benefits that displays a higher bioavailability compared to carotenoids such as lutein, β-carotene or lycopene. Several studies suggest its bioavailability displays an elevated interindividual variability. The aim of this work is to investigate whether a combination of SNPs is associated with this variability.

METHODS AND RESULTS

Thirty-seven healthy adult males consume a test meal that provides phytofluene from a tomato puree. Phytofluene concentrations are measured at fast and in chylomicrons at regular time intervals after meal intake. Identification of the combination of SNPs that best explained the interindividual variability of the phytofluene response is assessed by partial least squares regression. There is a large interindividual variability in the phytofluene response, with CV = 88%. Phytofluene bioavailability is positively correlated with fasting plasma phytofluene concentration (r = 0.57; p = 2 × 10^-4 ). A robust partial least squares regression model comprising 14 SNPs near or within 11 genes (ABCA1-rs2487059, rs2515629, and rs4149316, APOC1-rs445925, CD36-rs3211881, ELOVL5-rs6941533, FABP1-rs10185660, FADS3-rs1000778, ISX-rs130461, and rs17748559, LIPC-rs17240713, LPL-rs7005359, LYPLAL1-rs1351472, SETD7-rs11936429) explains 51% (adjusted R² ) of the interindividual variability in phytofluene bioavailability.

CONCLUSIONS

This study reports a combination of SNPs that is associated with a significant part of the interindividual variability of phytofluene bioavailability in a healthy male adult population.

Growth Temperature Influences Postharvest Quality and Cold Tolerance of Green Harvested Dwarf Tomatoes During Storage

Effect of cultivation temperature during the phase of flowering and fruit development on tomato quality was investigated. Plants of two dwarf tomato cultivars “Ponchi Re” and “Tarzan,” were subjected to three different growth temperatures: 16, 22, or 28°C, starting at the flowering phase. Mature green fruit was harvested and subjected to shelf life at 20°C for 20 days or first stored at 4°C for 15 days, and then placed under shelf life conditions. Fruit quality was determined through red color development, soluble solid content (SSC), softening, weight loss, and cold tolerance. Higher cultivation temperature increased development and production of fruit. Deviation from the 22°C growth temperature led to increased soluble solid content in both cultivars, and smaller fruit diameter in “Tarzan.” Fruit grown at lower temperature had delayed color development during shelf life, and this was further delayed by prior cold storage. “Tarzan” showed more chilling injury (CI) symptoms than “Ponchi Re.” In our experiment, SSC can be manipulated by modulating cultivation temperature, but that it is not associated with CI tolerance. Delayed color formation at the lowest growth temperature observed in “Ponchi Re” tomatoes could be resulted in lower lycopene levels leads to lower ROS scavenging capacity. For “Tarzan” tomatoes, higher firmness at harvest, less softening, and lower weight loss during cold storage in fruit from the lowest cultivation temperature might positively correlated with increased membrane integrity, resulting in increased CI tolerance. This indicates that CI incidence depends on growth temperature and is cultivar dependent in dwarf tomato fruit.

Advanced process analytical tools for identification of adulterants in edible oils - A review

This review summarizes the use of spectroscopic processes-based analytical tools coupled with chemometric techniques for the identification of adulterants in edible oil. Investigational approaches of process analytical tools such asspectroscopy techniques, nuclear magnetic resonance (NMR), hyperspectral imaging (HSI), e-tongue and e-nose combined with chemometrics were used to monitor quality of edible oils. Owing to the variety and intricacy of edible oil properties along with the alterations in attributes of the PAT tools, the reliability of the tool used and the operating factors are the crucial components which require attention to enhance the efficiency in identification of adulterants. The combination of process analytical tools with chemometrics offers a robust technique with immense chemotaxonomic potential. These involves identification of adulterants, quality control, geographical origin evaluation, process evaluation, and product categorization.

Impairment of carotenoid biosynthesis through CAR1 gene mutation results in CoQ10, sterols, and phytoene accumulation in Rhodotorula mucilaginosa

Red yeasts, mainly included in the genera Rhodotorula, Rhodosporidiobolus, and Sporobolomyces, are renowned biocatalysts for the production of a wide range of secondary metabolites of commercial interest, among which lipids, carotenoids, and other isoprenoids. The production of all these compounds is tightly interrelated as they share acetyl-CoA and the mevalonate pathway as common intermediates. Here, T-DNA insertional mutagenesis was applied to the wild type strain C2.5t1 of Rhodotorula mucilaginosa for the isolation of albino mutants with impaired carotenoids biosynthesis. The rationale behind this approach was that a blockage in carotenoid biosynthetic pathway could divert carbon flux toward the production of lipids and/or other molecules deriving from terpenoid precursors. One characterized albino mutant, namely, strain W4, carries a T-DNA insertion in the CAR1 gene coding for phytoene desaturase. When cultured in glycerol-containing medium, W4 strain showed significant decreases in cell density and fatty acids content in respect to the wild type strain. Conversely, it reached significantly higher productions of phytoene, CoQ₁₀, and sterols. These were supported by an increased expression of CAR2 gene that codes for phytoene synthase/lycopene cyclase. Thus, in accordance with the starting hypothesis, the impairment of carotenoids biosynthesis can be explored to pursue the biotechnological exploitation of red yeasts for enhanced production of secondary metabolites with several commercial applications. KEY POINTS: • The production of lipids, carotenoids, and other isoprenoids is tightly interrelated. • CAR1 gene mutation results in the overproduction of phytoene, CoQ₁₀, and sterols. • Albino mutants are promising tools for the production of secondary metabolites.

Low Oxygen Storage Improves Tomato Postharvest Cold Tolerance, Especially for Tomatoes Cultivated with Far-Red LED Light

We investigated the effects of low oxygen storage on chilling injury development, colour development, respiration and H₂O₂ levels of ‘Merlice’ tomatoes cultivated with and without far red (FR) LED lighting during 20 days of shelf-life. Mature green (MG) and red (R) tomatoes were stored at 2 °C in combination with 0.5, 2.5, 5 and 21 kPa O₂ for 15 days (experiment 1). MG tomatoes cultivated under either white LED or white LED light with FR LED light were stored at 2 °C in combination with 1, 5 and 21 O₂ kPa for 14 days (experiment 2). Chilled MG and R tomatoes from experiment 1 showed decay, firmness loss and higher weight loss during shelf-life which were reduced under low oxygen conditions. FR during cultivation improved chilling tolerance of MG tomatoes. Fastest colour development and lowest respiration rate during shelf-life were observed for MG fruit cultivated with FR lighting prior to storage at 1 kPa O₂/0 kPa CO₂. H₂O₂ levels during the shelf-life were not affected during cold storage. The improved cold tolerance of MG tomatoes cultivated with FR lighting is likely due to lower oxygen uptake that led to both higher lycopene synthesis and less softening.

Carotenoid composition and antioxidant activities of Chinese orange-colored tomato cultivars and the effects of thermal processing on the bioactive components

To facilitate the production of tomato products with high bioactivity and improve the utilization of orange-colored tomatoes, the carotenoids of 11 tomato cultivars were analyzed using high-performance liquid chromatography with photodiode array detection. Moreover, antioxidant activities were evaluated by four chemical-based assays, and the influences of thermal treatment on the carotenoids in orange-colored tomatoes rich in tetra-cis (7Z, 9Z, 7'Z, and 9'Z)-lycopene, phytofluene, and phytoene were studied. The nine orange-colored tomatoes (OT) were divided into two categories: OT-B, containing five cultivars rich in β-carotene, and OT-L, containing the other four cultivars that were abundant in tetra-cis-lycopene, phytofluene, and phytoene. The antioxidant activities of OT-L were higher than those of OT-B and the SD-2 cultivar in OT-L showed similar antioxidant activity to the red tomatoes. During thermal processing, tetra-cis-lycopene in SD-2 decreased about 38% after being exposed to heat for 2 hr at 80 °C, while its content was still higher than other lycopene isomers. Other-Z-lycopenes and all-trans (E)-lycopene increased from 2.36 ± 0.19 to 14.73 ± 1.16 µg/g fresh weight (FW) and 0.75 ± 0.10 to 5.91 ± 1.02 µg/g FW, respectively. Thus, thermal treatments at lower temperature, such as cold break and pasteurization, were more suitable for processing OT-L. The results demonstrated that OT-L could be an excellent raw material to produce tomato products with high bioavailability and bioactivity. The results of this research could provide helpful information for the research and development of tomato products using orange tomatoes and benefit planters and consumers. PRACTICAL APPLICATION: Some orange tomato cultivars are promising raw materials for tomato products because of their high contents of bioactive tetra-cis-lycopene, phytofluene, and phytoene. This study demonstrated the carotenoid components and antioxidant activities of the widely planted orange-colored tomatoes in China. The obtained knowledge, including the thermal processing effects on the isomerization and degradation of carotenoids in the cultivars, will offer useful information to food processors and benefit the consumers.

Engineering carotenoid production in mammalian cells for nutritionally enhanced cell-cultured foods

Metabolic engineering of mammalian cells has to-date focused primarily on biopharmaceutical protein production or the manipulation of native metabolic processes towards therapeutic aims. However, significant potential exists for expanding these techniques to diverse applications by looking across the taxonomic tree to bioactive metabolites not synthesized in animals. Namely, cross-taxa metabolic engineering of mammalian cells could offer value in applications ranging fromfood and nutrition to regenerative medicine and gene therapy. Towards the former, recent advances in meat production through cell culture suggest the potential to produce meat with fine cellular control, where tuning composition through cross-taxa metabolic engineering could enhance nutrition and food-functionality. Here we demonstrate this possibility by engineering primary bovine and immortalized murine muscle cells with prokaryotic enzymes to endogenously produce the antioxidant carotenoids phytoene, lycopene and β-carotene. These phytonutrients offer general nutritive value and protective effects against diseases associated with red and processed meat consumption, and so offer a promising proof-of-concept for nutritional engineering in cultured meat. We demonstrate the phenotypic integrity of engineered cells, the ability to tune carotenoid yields, and the antioxidant functionality of these compounds in vitro towards both nutrition and food-quality objectives. Our results demonstrate the potential for tailoring the nutritional profile of cultured meats. They further lay a foundation for heterologous metabolic engineering of mammalian cells for applications outside of the clinical realm.

Skin Carotenoids in Public Health and Nutricosmetics: The Emerging Roles and Applications of the UV Radiation-Absorbing Colourless Carotenoids Phytoene and Phytofluene

In this work, the importance of dietary carotenoids in skin health and appearance is comprehensively reviewed and discussed. References are made to their applications in health-promoting and nutricosmetic products and the important public health implications that can be derived. Attention is focused on the colourless UV radiation (UVR)-absorbing dietary carotenoids phytoene and phytofluene, which are attracting increased interest in food science and technology, nutrition, health and cosmetics. These compounds are major dietary carotenoids, readily bioavailable, and have been shown to be involved in several health-promoting actions, as pinpointed in recent reviews. The growing evidence that these unique UVR-absorbing carotenoids with distinctive structures, properties (light absorption, susceptibility to oxidation, rigidity, tendency to aggregation, or even fluorescence, in the case of phytofluene) and activities can be beneficial in these contexts is highlighted. Additionally, the recommendation that the levels of these carotenoids are considered in properly assessing skin carotenoid status is made.

Bioprospecting the Solar Panel Microbiome: High-Throughput Screening for Antioxidant Bacteria in a Caenorhabditis elegans Model

Microbial communities that are exposed to sunlight typically share a series of adaptations to deal with the radiation they are exposed to, including efficient DNA repair systems, pigment production and protection against oxidative stress, which makes these environments good candidates for the search of novel antioxidant microorganisms. In this research project, we isolated potential antioxidant pigmented bacteria from a dry and highly-irradiated extreme environment: solar panels. High-throughput in vivo assays using Caenorhabditis elegans as an experimental model demonstrated the high antioxidant and ultraviolet-protection properties of these bacterial isolates that proved to be rich in carotenoids. Our results suggest that solar panels harbor a microbial community that includes strains with potential applications as antioxidants.

Carotenoids: Experimental Ionization Energies and Capacity at Inhibiting Lipid Peroxidation in a Chemical Model of Dietary Oxidative Stress

Carotenoids are important natural pigments and micronutrients contributing to health prevention by several mechanisms, including their electron-donating (antioxidant) activity. In this work, a large series of carotenoids, including 11 carotenes and 14 xanthophylls, have been investigated by wavelength-resolved atmospheric pressure photoionization mass spectrometry (DISCO line of SOLEIL synchrotron), thus allowing the experimental determination of their ionization energy (IE) for the first time. On the other hand, the carotenoids have been also investigated for their ability to inhibit the heme iron-induced peroxidation of linoleic acid in mildly acidic micelles, a simple but relevant chemical model of oxidative stress in the gastric compartment. Thus, the carotenoids can be easily classified from IC₅₀ concentrations deduced from the time dependence of the lipid hydroperoxide concentration. With a selection of two carotenes and three xanthophylls a quantitative analysis is also provided to extract stoichio-kinetic parameters. The influence of the carotenoid structure (number of conjugated carbon-carbon double bonds, presence of terminal six-membered rings, hydroxyl, keto, and/or epoxy groups) on the IE, IC₅₀, and stoichio-kinetic parameters is discussed in details. The data show that the antioxidant activity of carotenes is well correlated to their electron-donating capacity, which itself largely depends on the length of the conjugated polyene chain. By contrast, the IE of xanthophylls is poorly correlated to the polyene chain length because of the strong, and sometimes unexpected, electronic effects of the O-atoms. Although IE remains an approximate predictor of the antioxidant activity of xanthophylls, other factors (interaction with the aqueous phase, competing radical-scavenging mechanisms, the residual activity of the antioxidant's oxidation products) probably play a significant role.

A global perspective on carotenoids: Metabolism, biotechnology, and benefits for nutrition and health

Carotenoids are lipophilic isoprenoid compounds synthesized by all photosynthetic organisms and some non-photosynthetic prokaryotes and fungi. With some notable exceptions, animals (including humans) do not produce carotenoids de novo but take them in their diets. In photosynthetic systems carotenoids are essential for photoprotection against excess light and contribute to light harvesting, but perhaps they are best known for their properties as natural pigments in the yellow to red range. Carotenoids can be associated to fatty acids, sugars, proteins, or other compounds that can change their physical and chemical properties and influence their biological roles. Furthermore, oxidative cleavage of carotenoids produces smaller molecules such as apocarotenoids, some of which are important pigments and volatile (aroma) compounds. Enzymatic breakage of carotenoids can also produce biologically active molecules in both plants (hormones, retrograde signals) and animals (retinoids). Both carotenoids and their enzymatic cleavage products are associated with other processes positively impacting human health. Carotenoids are widely used in the industry as food ingredients, feed additives, and supplements. This review, contributed by scientists of complementary disciplines related to carotenoid research, covers recent advances and provides a perspective on future directions on the subjects of carotenoid metabolism, biotechnology, and nutritional and health benefits.

Role of the p-Coumaroyl Moiety in the Antioxidant and Cytoprotective Effects of Flavonoid Glycosides: Comparison of Astragalin and Tiliroside

The aim of this study was to explore the role of p-coumaroyl in the antioxidant and cytoprotective effects of flavonoid glycosides. The antioxidant effects of astragalin and tiliroside were compared using ferric ion reducing antioxidant power, DPPH• scavenging, ABTS•⁺ scavenging, •O₂^– scavenging, and Fe²⁺-chelating assays. The results of these assays revealed that astragalin and tiliroside both exhibited dose-dependent activities; however, tiliroside exhibited lower IC₅₀ values than astragalin. In the Fe²⁺-chelating assay, tiliroside gave a larger shoulder-peak at 510 nm than astragalin, and was also found to be darker in color. Both of these compounds were subsequently evaluated in a Fenton-induced mesenchymal stem cell (MSC) damaged assay, where tiliroside performed more effectively as a cytoprotective agent than astragalin. Tiliroside bearing a 6′′-O-p-coumaroyl moiety exhibits higher antioxidant and cytoprotective effects than astragalin. The 6′′-O-p-coumaroyl moiety of tiliroside not only enhances the possibility of electron-transfer and hydrogen-atom-transfer-based multi-pathways, but also enhances the likelihood of Fe-chelating. The p-coumaroylation of the 6"-OH position could therefore be regarded as a potential approach for improving the antioxidant and cytoprotective effects of flavonoid glycosides in MSC implantation therapy.

Multivariate analyses of a wide selection of orange varieties based on carotenoid contents, color and in vitro antioxidant capacity

Carotenoids, color and in vitro antioxidant capacity were analyzed in twenty-two genotypes of oranges produced in Spain in two consecutive seasons. The colorless carotenoids phytoene and phytofluene were also analyzed. An important influence of the genotype on the carotenoid profile was observed. In most genotypes, such profile was characterized by the predominance of xanthophylls (82.7-93.0%), except in Cara Cara, with a higher proportion of carotenes (around 70.0%). β-cryptoxanthin was the predominant carotenoid in Rohde late and Ambersweet. The samples with the lowest carotenoid contents were the ones exhibiting the lowest Trolox Equivalent Antioxidant Capacity (TEAC) and vice versa. A formula obtained by multiple regression is proposed to estimate the TEAC value from the carotenoid content. No significant correlation between TEAC values and color coordinates were obtained, suggesting that color parameters are not good predictors of TEAC values. Lastly, the samples could be classify with a high rate of success (>90%) by Linear Discriminant Analysis based on color and carotenoids.

Protective Effect of Sinapine against Hydroxyl Radical-Induced Damage to Mesenchymal Stem Cells and Possible Mechanisms

As a phenolic alkaloid occurring in Cruciferous plants, sinapine was observed to protect mesenchymal stem cells (MSCs) against ·OH-induced damage in this study. It was also found to prevent DNA from damage, to scavenge various free radicals (·OH, ·O2(-), 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid diammonium salt) (ABTS)(+·), and 1,1-diphenyl-2-picrylhydrazyl radical (DPPH·)), and to reduce Cu(2+) to Cu(+). To further explore the mechanism, the end-product of sinapine reaction with DPPH· was determined using HPLC-electrospray ionization (ESI)-MS/MS and HPLC-diode array detector (DAD). Four molecular ion peaks (m/z 701, 702, 703, and 351) in HPLC-ESI-MS/MS analysis indicated a radical adduct formation (RAF) pathway; while a bathochromic shift (λ(max) 334→475 nm) in HPLC-DAD indicated the formation of quinone as the oxidized product of the phenolic -OH group. Based on these results, it may be concluded that, (i) sinapine can effectively protect against ·OH-induced damage to DNA and MSCs; such protective effect may provide evidence for a potential role for sinapine in MSC transplantation therapy, and be responsible for the beneficial effects of Cruciferous plants. (ii) The possible mechanism for sinapine to protect against ·OH-induced oxidative damage is radical-scavenging, which is thought to be via hydrogen atom (H·) transfer (HAT) (or sequential electron (e) proton transfer (SEPT))→RAF pathways.

Absorption and Distribution Kinetics of the 13C-Labeled Tomato Carotenoid Phytoene in Healthy Adults

BACKGROUND

Phytoene is a tomato carotenoid that may contribute to the apparent health benefits of tomato consumption. Although phytoene is a less prominent tomato carotenoid than lycopene, it is a major carotenoid in various human tissues. Phytoene distribution to plasma lipoproteins and tissues differs from lycopene, suggesting the kinetics of phytoene and lycopene differ.

OBJECTIVE

The objective of this study was to characterize the kinetic parameters of phytoene absorption, distribution, and excretion in adults, to better understand why biodistribution of phytoene differs from lycopene.

METHODS

Four adults (2 males, 2 females) maintained a controlled phytoene diet (1-5 mg/d) for 42 d. On day 14, each consumed 3.2 mg (13)C-phytoene, produced using tomato cell suspension culture technology. Blood samples were collected at 0, 1-15, 17, 21, and 24 h and 2, 3, 4, 7, 10, 14, 17, 21, and 28 d after (13)C-phytoene consumption. Plasma-unlabeled and plasma-labeled phytoene concentrations were determined using ultra-HPLC-quadrupole time-of-flight-mass spectrometry, and data were fit to a 7-compartment carotenoid kinetic model using WinSAAM 3.0.7 software.

RESULTS

Subjects were compliant with a controlled phytoene diet, consuming a mean ± SE of 2.5 ± 0.6 mg/d, resulting in a plasma unlabeled phytoene concentration of 71 ± 14 nmol/L. A maximal plasma (13)C-phytoene concentration of 55.6 ± 5.9 nM was achieved 19.8 ± 9.2 h after consumption, and the plasma half-life was 2.3 ± 0.2 d. Compared with previous results for lycopene, phytoene bioavailability was nearly double at 58% ± 19%, the clearance rate from chylomicrons was slower, and the rates of deposition into and utilization by the slow turnover tissue compartment were nearly 3 times greater.

CONCLUSIONS

Although only differing from lycopene by 4 double bonds, phytoene exhibits markedly different kinetic characteristics in human plasma, providing insight into metabolic processes contributing to phytoene enrichment in plasma and tissues compared with lycopene. This trial was registered at clinicaltrials.gov as NCT01692340.

DFT study on the quenching mechanism of singlet oxygen by lycopene

The quenching mechanism of singlet oxygen by lycopene is analyzed based on DFT calculations at the B3LYP/6-311+(d,p) level.

Squalestatin is an inhibitor of carotenoid biosynthesis in Plasmodium falciparum

The increasing resistance of malaria parasites to almost all available drugs calls for the characterization of novel targets and the identification of new compounds. Carotenoids are polyisoprenoids from plants, algae, and some bacteria, and they are biosynthesized by Plasmodium falciparum but not by mammalian cells. Biochemical and reverse genetics approaches were applied to demonstrate that phytoene synthase (PSY) is a key enzyme for carotenoid biosynthesis in P. falciparum and is essential for intraerythrocytic growth. The known PSY inhibitor squalestatin reduces biosynthesis of phytoene and kills parasites during the intraerythrocytic cycle. PSY-overexpressing parasites showed increased biosynthesis of phytoene and its derived product phytofluene and presented a squalestatin-resistant phenotype, suggesting that this enzyme is the primary target of action of this drug in the parasite.