Showing papers on "Neoxanthin published in 2022"

Heat and Light Stability of Pumpkin-Based Carotenoids in a Photosensitive Food: A Carotenoid-Coloured Beverage

Abstract: This study aimed to evaluate carotenoid degradation kinetics in a beverage coloured with pumpkin juice concentrate during storage at dark and illuminated conditions at four temperatures (10, 20, 35 and 45 °C). Carotenoids were quantified by HPLC-DAD, and kinetic parameters for carotenoid degradation were estimated by one-step nonlinear regression analysis. During dark storage, degradation kinetics was modelled by fractional conversion (all-trans-β-carotene) and zero-order equations (all-trans-antheraxanthin, all-trans-lutein, all-trans-violaxanthin and all-trans-neoxanthin). Storage of samples in a climatic chamber with intense light intensity (1875–3000 lux) accelerated the carotenoid losses. At illuminated conditions, degradation followed a first-order (all-trans-lutein, all-trans-violaxanthin and all-trans-neoxanthin) and fractional conversion model (all-trans-β-carotene and all-trans-antheraxanthin). Carotenoid degradation followed an Arrhenius temperature-dependency, with Ea values lower than 50 kJ/mol. Degradation was shown to be mainly by oxidative reactions. Packaging under minimal oxygen conditions, use of antioxidants (e.g., ascorbic acid), and proper choice of light sources at retail shelves may be considered to optimize the pigment retention in a carotenoid-coloured beverage during storage.

Purification and use of carotenoid standards to quantify cis-trans geometrical carotenoid isomers in plant tissues.

Abstract: Reverse-phase high-performance liquid chromatography (HPLC) is a preferred method used to identify and quantify carotenoids. Here, we describe a straightforward, reliable, and cost-effective protocol to purify and develop individual carotenoid standards for absolute quantification of carotenoids, including selected cis-trans (geometric) isomers. Analytical techniques to extract, purify and collect individual carotenoids using an HPLC system equipped with a Diode Array Detector (DAD) and fraction collector are described. Carotenoids were separated and identified by their characteristic ultraviolet-visible (UV-Vis) absorption spectra and individually isolated based on their retention times using a C30 column. This chapter outlines how to prepare standard calibration curves using known quantities of purified and/or commercially available carotenoids. A series of molar extinction and slope coefficients for phytoene, phytofluene, ζ-carotene, neurosporene, pro-lycopene, all trans-lycopene, lutein, β-carotene, zeaxanthin, antheraxanthin, violaxanthin, neoxanthin, capsanthin, capsorubin and β-cryptoxanthin are defined to enable absolute quantification of their abundance in plant, animal, and bacterial tissues. Different approaches for reporting carotenoid abundance by absolute concentration, relative composition, and/or using ratios of different pigments are provided as a convenient resource for carotenoid researchers.

A DUF4281 domain-containing protein (homologue of ABA4) of Phaeodactylum tricornutum regulates the biosynthesis of fucoxanthin

Abstract: Although fucoxanthin is one of the most valuable carotenoids, its biosynthesis pathway is still poorly understood. Neoxanthin has been regarded as the intermediate of fucoxanthin in recent years, however, multiple details still need to be explored. Previous study performed in Arabidopsis thaliana demonstrated a DUF4281-domain containing protein (ABA4) was necessary for the biosynthesis of neoxanthin, and the mutation of ABA4 led to a huge alteration of pigment composition. In Phaeodactylum tricornutum, a function unknown protein (designated as PtABA4 in this study) displayed high homology to ABA4, and also contained DUF4281 domain. To investigate its function on neoxanthin synthesis and fucoxanthin accumulation, we conducted endogenous overexpression and knockdown (RNA interference) of PtABA4 individually, as well as in vitro activity assay using recombinant protein. The overexpression and knockdown of PtABA4 lead to sharp increases and decrease of fucoxanthin, respectively, demonstrating a key role of PtABA4 on fucoxanthin accumulation. Unexpectedly, the knockdown of PtABA4 results in the decreases of upstream carotenoids of neoxanthin, rather than compensatory increases. In terms of in vitro activity assay, neither the recombinant protein produced by Escherichia coli nor the overexpressed transformant displays neoxanthin synthase activity. Taking all results into consideration, we speculate that the PtABA4 may constitute one multienzyme complexes with other membrane associated enzymes and participate in the formation of several carotenoids, rather than neoxanthin only. The ubiquity of DUF4281 domain across all taxa and the absence of xanthophylls in bacteria provide indirect evidence for our assumption. Above all, this study here provides a target gene for enhancing the fucoxanthin content by genetic engineering methods, and deeps the understanding about the function of DUF4281 domain.

Characterization of complex photosynthetic pigment profiles in European deciduous tree leaves by sequential extraction and reversed-phase high-performance liquid chromatography

Abstract: Leaf pigments, including chlorophylls and carotenoids, are important biochemical indicators of plant photosynthesis and photoprotection. In this study, we developed, optimized, and validated a sequential extraction and liquid chromatography-diode array detection method allowing for the simultaneous quantification of the main photosynthetic pigments, including chlorophyll a, chlorophyll b, β-carotene, lutein, neoxanthin, and the xanthophyll cycle (VAZ), as well as the characterization of plant pigment derivatives. Chromatographic separation was accomplished with the newest generation of core–shell columns revealing numerous pigment derivatives. The sequential extraction allowed for a better recovery of the main pigments (+25 % chlorophyll a, +30 % chlorophyll b, +42 % β-carotene, and 61% xanthophylls), and the characterization of ca. 5.3 times more pigment derivatives (i.e., up to 62 chlorophyll and carotenoid derivatives including isomers) than with a single-step extraction. A broad working range of concentrations (300–2,000 ng.mL−1) was achieved for most pigments and their derivatives and the limit of detection was as low as a few nanograms per milliliter. The method also showed adequate trueness (RSD < 1%) and intermediate precision (RSD < 5%). The method was developed and validated with spinach leaves and their extracts. The method was successfully performed on leaf pigment extracts of European deciduous tree species. Within a case study using Fagus sylvatica L. leaves, pigment derivatives revealed a high within-individual tree variability throughout the growing season that could not be detected using the main photosynthetic pigments alone, eventually showing that the method allowed for the monitoring of pigment dynamics at unprecedented detail.

Pigment-Related Mutations Greatly Affect Berry Metabolome in San Marzano Tomatoes

Abstract: The study describes the alterations in metabolomic profiles of four tomato fruit mutations introgressed into Solanum lycopersicum cv. San Marzano, a well-known Italian traditional variety. Three lines carrying variants affecting the content of all pigments, high pigment-1 (hp-1), hp-2, pigment diluter (pd), and a combination of Anthocyanin fruit and atroviolaceum (Aft_atv), were selected, and characterized. Biochemical analysis of 44 non-polar, 133 polar, and 65 volatile metabolites in ripe fruits revealed a wide range of differences between the variant lines and the recurrent parent San Marzano. Among non-polar compounds, many carotenoids, plastoquinones, and tocopherols increased in the fruit of high pigment lines, as well as in Aft_atv, whose β-carotene levels increased too. Interestingly, pd displayed enriched levels of xanthophylls (all-trans-neoxanthin and luteoxanthin) but, simultaneously, decreased levels of α-and β-/γ-tocopherols. Looking at the metabolites in the polar fraction, a significant decrease in sugar profile was observed in hp-1, pd, and Aft_atv. Conversely, many vitamins and organic acids increased in the hp-2 and Aft_atv lines, respectively. Overall, phenylpropanoids was the metabolic group with the highest extent of polar changes, with considerable increases of many compounds mainly in the case of Aft_atv, followed by the pd and hp-2 lines. Finally, several flavor-related compounds were found to be modified in all mutants, mostly due to increased levels in many benzenoid, lipid, and phenylalanine derivative volatiles, which are associated with sweeter taste and better aroma. Construction of metabolic maps, interaction networks, and correlation matrices gave an integrated representation of the large effect of single variants on the tomato fruit metabolome. In conclusion, the identified differences in the mutated lines might contribute to generating novel phenotypes in the traditional San Marzano type, with increased desirable nutraceutical and organoleptic properties.

Spectral properties and stability of selected carotenoid and chlorophyll compounds in different solvent systems

Abstract: A quick, accurate, and low-cost analytical method for the assessment of bioactive leaf pigments, such as carotenoids and chlorophylls, can be beneficial for plant growers and consumers. The objective of this study was to learn about the thermal stability of major plant pigments and investigate the potential for rapid extraction and quantification of individual compounds in leafy greens. In this study, the spectral properties and chemical stability of violaxanthin, neoxanthin, lutein, zeaxanthin, β-carotene, and chlorophyll a and b pigments were examined in different solvent systems. Within the same solvent system, bathochromic shifts were observed in the analysis of carotenoids that contain a higher number of conjugated double bonds. Depending on the solvent system, pigments exhibited different degrees of stability. The results from this study can be used to identify an ideal solvent system for the storage of pigment standards and for the analysis of these pigments in leaf samples using UV-VIS spectroscopy.

Responses of the growth, photosynthetic characteristics, endogenous hormones and antioxidant activity of Carpinus betulus L. seedlings to different light intensities

Abstract: Light is an important ecological factor that affects plant growth, survival and distribution. Carpinus betulus L. is native to central Europe and is used as an ornamental plant with strong adaptability. It is an important tree species for landscaping and timber use. What’s more, the antioxidant- and anticancer-related properties of C. betulus leaf extracts are remarkable, that make it a possible raw material for medicine. Light intensity is an important environmental factor affecting the growth and physicochemical changes of C. betulus, but the mechanism of its effect on this species still remains unknown. In this study, the growth, photosynthetic characteristics, endogenous hormones and antioxidant activity responses of C. betulus seedlings to four light intensity gradients (T0: normal light; T1: 75%; T2: 50%; T3: 25% of normal light) were studied after 60 days of shading treatments. The results showed a significant effect of low light intensity on the values of the growth and physiological parameters of C. betulus. The low light intensity caused the inhibition of plant biomass accumulation and the degradation of photosynthetic capacity and stomatal behavior and aggravated the cell membrane lipid peroxidation. However, the plant height growth, leaf area, specific leaf area, photosynthetic pigment content, and contents of GA3 and ABA of C. betulus increased with decreasing light intensity. We found that C. betulus can tolerate mild (T1) and moderate (T2) shading stress by developing photoprotective mechanisms and maintaining relatively high concentrations of organic osmolytes and high antioxidant enzyme activities (superoxide dismutase, peroxidase, catalase and ascorbate peroxidase), but the ability of C. betulus to synthesize osmotic substances and enzymatic antioxidants was impaired under severe shading conditions (T3). Our results suggest that C. betulus can make effective use of low light resources by adjusting its morphology, material distribution, photosynthetic rate and antioxidant enzyme system in suitable low-light environments (50%~75% of normal light); however, light intensity levels that are too low (25% of normal light) will have adverse effects on plant growth. The results of this study provide not only new insights into the response mechanisms of C. betulus to light intensity but also a scientific basis for the cultivation and application of C. betulus in China.

Controlling Light to Optimize Growth and Added Value of the Green Macroalga Codium tomentosum

Abstract: Codium tomentosum is a recently domesticated green macroalga, being currently cultured as an extractive species in integrated multi-trophic aquaculture (IMTA). Optimization of light requirements in outdoor systems must be achieved to increase the market value of cultivated algal biomass. The present study addresses the seasonal effects of light intensity and wavelength on productivity, pigment composition and epiphyte overgrowth in C. tomentosum cultured in a land-based IMTA system. Exposure to high light (non-filtered sun light) lead to higher net productivities in spring. However, non-filtered sun light caused significantly reduced productivities during summer when compared to filtered sun light (~ 4x lower irradiance levels). Furthermore, lower photosynthetic capacity (Fv/Fm) was observed in macroalgae cultured under high light during summer, indicating photoinhibition. Treatments with filtered sun light (low and red light) showed intermediate and more stable productivities. Epiphyte biomass was higher under high light and the lowest epiphyte overgrowth was recorded under red light. Concentrations of light-harvesting pigments were lower in summer than in spring, indicating a seasonal photoacclimation of macroalgae. An opposite seasonal trend was observed for accessory xanthophylls, as the main role of these pigments is photoprotection. Higher all-trans-neoxanthin and violaxanthin concentrations were found in high light than in low or red light treatments, confirming the important role of these biomolecules in the photoprotection of C. tomentosum. This study underlines the importance of controlling light to optimize algal growth outdoors and enhance the production of high-value compounds (i.e., pigments). Additionally, this practice can also reduce epiphyte overgrowth, thus enhancing the valorization of macroalgal biomass derived from C. tomentosum aquaculture.

Analysis of geometrical isomers of dietary carotenoids.

Abstract: Carotenoids are versatile isoprenoids of great importance in food science and nutrition. These compounds are natural colorants and key to combat vitamin A deficiency, a major global nutritional problem. In addition, carotenoids have health-promoting biological actions that can contribute to reduce the risk of serious diseases, including cancer, cardiovascular disease, skin, bone and eye conditions and metabolic disorders. Beneficial roles of carotenoids in cognition and fetal development are also attracting increased attention. The presence of double bonds cause carotenoids to be prone to geometrical isomerization. The distinction among geometrical isomers of carotenoids is important as there can be important differences in terms of bioavailability, stability during processing or even biological actions. This chapter summarizes strategies to separate and tentatively identify geometrical isomers of major dietary carotenoids (neoxanthin, violaxanthin, lutein, zeaxanthin, β-cryptoxanthin, α-carotene, β-carotene, lycopene, phytoene and phytofluene).

Relationship among light intensity, pigment compositions and photoinhibition in relation to rhodoxanthin accumulation in the gymnosperm Cryptomeria japonica

Abstract: ABSTRACT Some gymnosperms, including Cryptomeria japonica, exhibit needle reddening caused by red xanthophyll pigment, rhodoxanthin accumulation during long-term cold acclimation. Although photoprotective role of rhodoxanthin, serves as a “sunscreen”, was proposed, the key environmental and/or physiological factors involved in rhodoxanthin accumulation remain unclear. We exposed C. japonica trees to four different light intensities (13%, 39%, 64% and 100% of full sunlight) and measured some parameters (the nocturnal de-epoxidation state [DPS: ratio of the zeaxanthin + antheraxanthin to xanthophyll cycle pigments], the β-carotene level and the maximum photosystem II efficiency [Fv/Fm]) that have been suggested to play roles in rhodoxanthin accumulation. Rhodoxanthin was synthesised from autumn to winter, and less so in spring. Light intensity related to the maximum value of rhodoxanthin on chlorophyll (Chl) basis, but not to that on FW basis, because Chl content decreased with increasing light intensity. These results indicated that rhodoxanthin accumulation was accompanied with Chl decrease. In addition, the relationship between the rhodoxanthin content and the seasonal growth temperature was different among light treatments, reflecting differences in the amount of excess light among light treatments Furthermore, the rhodoxanthin content correlated significantly with the Fv/Fm, nocturnal DPS and β-carotene level in winter. Thus, rhodoxanthin accumulates in a photoinhibitory environment occurs with a decrease in Chl content and an increase in DPS.

UV Radiation Induces Specific Changes in the Carotenoid Profile of Arabidopsis thaliana

Abstract: UV-B and UV-A radiation are natural components of solar radiation that can cause plant stress, as well as induce a range of acclimatory responses mediated by photoreceptors. UV-mediated accumulation of flavonoids and glucosinolates is well documented, but much less is known about UV effects on carotenoid content. Carotenoids are involved in a range of plant physiological processes, including photoprotection of the photosynthetic machinery. UV-induced changes in carotenoid profile were quantified in plants (Arabidopsis thaliana) exposed for up to ten days to supplemental UV radiation under growth chamber conditions. UV induces specific changes in carotenoid profile, including increases in antheraxanthin, neoxanthin, violaxanthin and lutein contents in leaves. The extent of induction was dependent on exposure duration. No individual UV-B (UVR8) or UV-A (Cryptochrome or Phototropin) photoreceptor was found to mediate this induction. Remarkably, UV-induced accumulation of violaxanthin could not be linked to protection of the photosynthetic machinery from UV damage, questioning the functional relevance of this UV response. Here, it is argued that plants exploit UV radiation as a proxy for other stressors. Thus, it is speculated that the function of UV-induced alterations in carotenoid profile is not UV protection, but rather protection against other environmental stressors such as high intensity visible light that will normally accompany UV radiation.

Integrated Metabolome and transcriptome analysis revealed carotenoid metabolism difference in pepper (&lt;i&gt;Capsicum annuum L.&lt;/i&gt;) yellowing mutants under different light quality

Abstract: Light is an important environmental factor for plant growth and development, different light qualities have different regulatory effects on plants. To investigate the effect of light quality on plants, we determined the physiological characteristics, transcriptome and metabolome analysis of pepper yellowing mutants yl1 treated with blue, red, green, and purple light. Results showed that the leaf of yl1 was obviously yellowing, and the contents of chlorophyll, carotenoid and net photosynthetic rate in yl1 were significantly decreased under purple light. A total of 31,853 genes were quantified under blue, red, green and purple light. The genes related to carotenoid metabolism pathway such as PSY, LUT5 and VDE were significantly increased, while the expression levels of chlorophyll synthesis related genes POR and CAO were significantly decreased under purple lught. At the same time, twenty-one carotenoid pathway metabolites were detected under the four light, and ten metabolites were more abundant in pepper leaves. α-carotene, β-carotene, lutein, neoxanthin, α-cryptoxanthin and β-cryptoxanthin were significantly accumulated under blue, red and green light. However, zeaxanthin and antheraxanthin were accumulated in large quantities under purple light. After silencing CaVDE gene under purple light, leaf etiolation degree was significantly weakened, chlorophyll, carotenoids and net photosynthetic rate were significantly increased, and the accumulation of zeaxanthin and antheraxanthin was significantly decreased. These results provide a reference for analyzing the changes of carotenoid components induced by VDE in purple light and provide new insights into the mechanism of leaf color change in plants.

Isolation and characterization of a neoxanthin synthase gene functioning in fucoxanthin biosynthesis of Phaeodactyum tricornutum

Abstract: Golden-brown xanthophyll fucoxanthin in marine organisms, especially in diatoms, has attracted widespread attention because of its diverse biological activities. However, the biosynthetic pathway of fucoxanthin remains unclear in diatoms. Fucoxanthin may derive from either neoxanthin or diadinoxanthin pathway. However, the key point is whether neoxanthin and its synthesizing genes exist or not. In this study, we successfully identified a few xanthophylls in trace amounts in the concentrated fraction of carotenoids of diatom Phaeodactylum tricornutum cultured at different light intensities with the co-chromatography method, and cloned the neoxanthin synthase (NXS) gene which was not annotated in diatom genome. The NXS knockdown and knockout experiment show a positive correlation in the accumulation of neoxanthin and zeaxanthin while a negative correlation in violaxanthin and fucoxanthin with the expression of NXS. In vitro assay evidenced that neoxanthin is the precursor for fucoxanthin biosynthesis, indicating that other molecules intermediate the conversion between violaxanthin and fucoxanthin. Overall, we cloned a novel gene functioning in neoxanthin biosynthesis, which should aid to clarifying the fucoxanthin biosynthetic pathway in diatom.

Evaluation of Cellular Uptake and Removal of Chlorpropham in the Treatment of Dunaliella salina for Phytoene Production

Abstract: Chlorpropham is a carbamate herbicide that inhibits cell division and has been widely used as a potato sprout suppressant. Recently we showed that the microalga Dunaliella salina treated with chlorpropham massively accumulated the colourless carotenoids phytoene and phytofluene. Phytoene and phytofluene are valued for their antioxidant, UV-absorption and skin protectant properties; however, they are present in very low quantities in nature. The low toxicity herbicide chlorpropham seems a promising catalyst to produce phytoene in large quantities from CO2 and solar energy with D. salina. This study explored chlorpropham uptake by the algal cells, the formation of potential intermediate metabolites, and the removal of residual chlorpropham from harvested D. salina biomass. Algal biomass rapidly concentrated chlorpropham from culture media. However, washing the harvested biomass with fresh culture medium twice and five times removed ~83 and ~97% of the chlorpropham from the biomass, respectively, and retained algal cell integrity. Furthermore, chloroaniline, a common metabolite of chlorpropham degradation, was not detected in chlorpropham-treated cultures, which were monitored every two days for thirty days. Cells treated with chlorpropham for either 10 min or 24 h continued to over-accumulate phytoene after resuspension in an herbicide-free medium. These data imply that whilst Dunaliella cells do not possess the intracellular capacity to degrade chlorpropham to chloroaniline, the effect of chlorpropham is irreversible on cell nuclear division and hence on carotenoid metabolism.

Carotenoid composition and investigation of the antioxidant activity of Phormidium sp

Abstract: Microalgae metabolites are used for the health, feed additives, cosmetic industries, food and biodiesel production. Phormidium species have an important position in medical studies because they contain essential components. In this study, carotenoid profile and content were analyzed using HPLC method. Antioxidant activities for Phormidium sp. were determinated using DPPH and FRAP assays. BHT and ASC were used as control samples in antioxidant assays. The saponified extract to seperate a range of carotenoids, verified a suitable separation as inferred from the retention factor (k) among 0.54 - 3.83 and the separation factor (α) values more than 1. Resolution peaks appointed to carotenoids (16) for Phormidium sp. was attained within the period time of 45 min. In the specie, main carotenoids identified were cis-Lutein, All-trans-lutein, All-transzeaxanthin, 13-or 13’-β-carotene, All-trans-β-carotene and 9-or 9’-cis-β-carotene. Auroxanthin and cisneoxanthin were identified as epoxy-containing compounds. It is also understood that considering the DPPH assay, the extract of Phormidium sp. (IC50:127.6 mg/L) exhibited clearly low radical scavenging activity compared to the standards ASC (IC50: 0.02 mg/L) and BHT (IC50: 0.19 mg/L). In the FRAP antioxidant experiment, the mean ASC and BHT equivalent amounts were determined as 828.6 and 124.6 mg/L, respectively. Quantitatively, Phormidium sp. was predominated by cis-Lutein as a major constituent, being 41.35 % (3.02 mg/g) in total carotenoids (Tc). The antioxidant capacity of Phormidium sp. that considering the DPPH and FRAP were compared to control standards were showed considerably low effects.